News from GERSTEL GmbH & Co. KG Eberhard-Gerstel-Platz Mülheim an der Ruhr Germany Phone + 49 (0)

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1 Versatile autosampler and sample preparation robot G L O B A L A N A L Y T I C A L S O L U T I O N S News from GERSTEL GmbH & Co. KG Eberhard-Gerstel-Platz Mülheim an der Ruhr Germany Phone + 49 (0) gerstel@gerstel.com No. 11 ISSN THE NEW MultiPurpose Sampler MPS GERSTEL MultiPurposeSampler MPS THE NEW MPS MultiPurpose Sampler Centerfold From the Mountains to the Ocean Ultratrace Analysis with the GERSTEL- FOOD SAFETY FLAVOR PROFILING WHISKEY AND WINE ENVIRONMENTAL

2 GERSTEL Solutions worldwide No. 11 INNOVATION The new MPS: Driving productivity page 3 Novel automated Pyrolyzer for the GERSTEL TDU page 24 ENVIRONMENTAL POP traces in icy heights page 4 FOOD SAFETY Polyaromatic seafood platter? page 7 Pesticides: So long, troublemakers I (GC-MS/MS) page 19 Pesticides: So long, troublemakers II (LC-MS/MS) page 22 OFF-FLAVORS Wine: Efficient and sensitive determination of TCA and other off-flavors page 9 FLAVOR PROFILING Beverages: Put on the 1D/2D goggles page 13 Whiskey: See the big picture and every little detail page 16 NEWS GERSTEL on expansion course in South East Asia page 12 Multi-Desorption Mode TD page 12 THE NEW MPS Centerfold GERSTEL MultiPurposeSampler MPS Versatile autosampler and sample preparation robot THE NEW MultiPurpose Sampler MPS 2 GERSTEL Solutions Worldwide No. 11

3 Innovation The new MPS: Driving productivity Since its introduction, the GERSTEL MPS (MultiPurpose Sampler) has been installed in several thousand laboratories, making it one of the most widely sold sample preparation and sample introduction robots for GC/MS and LC/MS. With this kind of success, it only makes sense to stick with the proven concept when developing the next generation. The new MPS delivers improved productivity and performance and provides an advanced platform for future developments. Externally, the sleek and modern look is the first thing that strikes most people when they see the new MPS. As always, though, the magic is in the detail. The electronics of the MPS have been unified and brought up to the latest standards. A LAN port was added along with additional memory capacity giving the analyst more freedom to operate with multiple instrument configurations. The new MPS supports all GERSTEL sample preparation and sample introduction technologies. All options are easily and intuitively operated using the MAE- More details... about the new MPS can be found in the centerfold insert in this magazine. STRO software. The PrepAhead function enables parallel sample preparation and analysis, perfectly synchronized for optimized system utilization. The GC/MS or LC/MS system typically never has to wait for the next injection when it becomes ready after a run. MAESTRO operates independently or fully integrated with Agilent ChemStation or GC MassHunter. The new MPS helps you further improve performance and productivity of your GC/MS or LC/MS analysis. A glance at the application details provides some clues to the added value that the MPS can bring to your lab. The MPS helps you automate your sample preparation: Matrix residue is eliminated using SPE or dispersive SPE (DPX); standards or reagents can be added; dilution series created; analytes concentrated for improved limits of detection, for example, using D y namic Headspace (DHS), Stir Bar Sorptive Extraction (SBSE) or Solid Phase Micro-Extraction (SPME). An innovation in the range of options is Dynamic Load & Wash (DLW), which is used to eliminate carry-over between LC/MS injections. A l l s a m p l e preparation steps are easily, flexibly and intuitively entered by mouse-click in the MAESTRO software, and the daily sequence table is quickly generated using intelligent fill-down and copy functions. The new MPS is your reliable platform for GC/MS and LC/MS sample preparation and sample introduction for the coming years. Eberhard G. Gerstel Dear reader, It is the goal of GERSTEL Solutions Worldwide magazine to take you on an excursion through the world of chemical analysis to laboratories all over the globe that use GERSTEL solutions in their daily work. Technical aspects regarding the instrumentation used are of course important, but first and foremost we want to focus on the application. In the 11th issue of our magazine, we report on several interesting themes ranging from the highest mountains to the deep blue sea: We visit the Andes with a team of scientists to find traces of polychlorinated biphenyls (PCBs) on the Cerro Aconcagua, the highest mountain in the Americas. We report on how pesticides can easily and efficiently be determined in food and we look at how the largest oil spill in recent history has brought a lot of changes to chemical analysis applications in the field of food safety. Further, we go on a sensory tour de force, poking our nose and our Twisters in wine, whiskey and other beverages looking for desirable and undesirable flavors. Last, but not least, the centerfold in this issue is an attractive and informative addition, featuring the new GERSTEL MPS, which forms the basis for much of the application work we present. The GERSTEL MPS has been installed in several thousand laboratories over the years making it one of the most widely sold sample preparation and sample introduction robots for GC/MS and LC/MS. Externally, the sleek and modern look is the first thing that strikes most people when they see the new MPS. As always, the magic is in the detail Enjoy the magazine! Sincerely, E b e r h a r d G. G e r s t e l President / Co-Owner GERSTEL Solutions Worldwide No. 11 3

4 An expedition of scientists crosses the Poland glacier during the ascent of the eastern slopes of Cerro Aconcagua (6962 m), the highest mountain in the Americas. The mission of the scientists is to sample snow at levels above 6000 meters to determine the accumulation of airborne pollutants brought to the southern hemisphere by long range atmospheric transport (LRAT). Environmental POP traces in icy heights A team of scientists from Chile, Spain and Germany have found polychlorinated biphenyls (PCBs) in the snow of the high Andes Mountains at elevations above 6000 meters. While the GC/MS analysis involved is straight forward, new paths had to be trodden to improve the sample preparation and reduce the amount of sample that needed to be carried to the laboratory. The scientists found an ultra-sensitive solution: Stir Bar Sorptive Extraction (SBSE). Snow is a fascinating material - and not just in the eyes of children of all ages racing down snowy slopes on a sunny winters day. Even scientists preoccupied with the whereabouts of persistent organic pollutants (POPs) in the environment can apparently develop a weakness for snow. Chilean, Spanish, and German scientists, among them experts from the Helmholtz Center for Environmental Research (UFZ) in Leipzig, Germany, went on an expedition to South America. Their goal was the eternal snow cap of the Cerro Aconcagua, at 6962 meters the highest mountain in the Americas. In the elevated snow repository, the scientists hoped to find deeper answers to the whereabouts and long range atmospheric transport of polychlorinated biphenyls (PCBs) in the southern hemisphere. PCBs along with several pesticides, industrial chemicals and incineration products belong to the «dirty dozen» of organic chemicals that are also known as persistent organic pollutants (POPs). The Stockholm Convention on Persistent Organic Pollutants is an international environmental treaty that aims to eliminate or restrict the production and use of POPs. The treaty was signed in May 2001, outlawing nine of the «dirty dozen» chemicals, limiting the use of DDT to malaria control, and curtailing inadvertent production of dioxins and furans. Until the 1980 s, PCBs were widely used as insulating oil and refrigerant in transformers and capacitors, as hydraulic fluids, and as plasticizers. According to the US EPA, PCBs have been demonstrated to cause adverse health effects in animals such as can- 4 GERSTEL Solutions Worldwide No. 11

5 cer and a number of serious non-cancer health effects, including effects on the immune system, reproductive system, nervous system, endocrine system and other health effects. Studies in humans provide supportive evidence for potential carcinogenic and non-carcinogenic effects. PCBs accumulate in fat tissue and reach the human body through the food chain. To determine the degree to which PCBs are present in the environment, samples must be taken and chemical analysis performed. This is the only way to gauge whether international treaties are being adhered to. But why head for the glaciers in the high Andes with your back pack? Scientists agree: Due to their high porosity and resulting high specific surface, ice crystals are more efficient than rain drops at extracting pollutants from the atmosphere. The only condition that must be met is that temperatures permanently stay below the freezing point of water to conserve the fallen snow until it is sampled, and temperatures below 0 C is a given at 6000 meters above sea level. The idea behind the project of the scientists was to analyze the icy precipitate in order to gain insights as to the type, accumulation, and transport paths of POPs in the atmosphere. POPs like PCBs and organochlorine pesticides are mainly deposited and accumulated in colder regions of the world according to an article by Quiroz et al. in Environmental Chemistry Letters (2009, 7: ). Studies of PCB concentrations in snow from the arctic region and from the highest elevations in Europe and Canada have further shown that pollutants are distributed globally through Long Range Atmospheric Transport (LRAT). In the Andes Mountains, PCBs have been found in snow as well as in various solid, liquid, and gaseous matrices. Influence of High Mountain Ranges ant concentrations are often very low. This, according to Quiroz et al., means that in order to reach the required lower limits of determination large sample volumes have to be lugged over long distances under adverse conditions from alpine glaciers at very high altitudes to the laboratory. The international team of scientists therefore started out by investigating how the analysis could be performed satisfactorily based on smaller, more easily transportable sample amounts. It s all about the extraction technique The solution to the high-altitude conundrum was found to be Stir Bar Sorptive Extraction (SBSE) using the GERSTEL Twister. The Twister is a patented magnetic stir bar covered with a thick layer of polydimethylsiloxane (PDMS), a highly efficient sorbent and extraction phase. While the Twister stirs the aqueous sample, organic chemical compounds are efficiently extracted and absorbed into the PDMS. Using thermal desorption, analytes are subsequently transferred quantitatively to a GC/MS system resulting in ultrahigh sensitivity and lowest possible limits of determination. Depending on the analytes in question and the sample volume extracted, SBSE can be up to 1000 times more sensitive than SPME. SBSE is extremely simple to perform. The Twister is added to the sample and allowed to stir for 1-2 hours. The Twister is then removed, dried using lint-free paper cloth, and placed in the autosampler tray. Thermal desorption is performed using a GERSTEL Thermal Desorption System (TDS) or Thermal Desorption Unit (TDU) in combination with a MultiPurpose Sampler (MPS). Either system can be connected with a GC/MS system that is used to separate and determine the individual compounds. In the snow of the high Andes, Roberto Quiroz and his colleagues discovered mainly the most stabile PCBs such as hexachlorobiphenyl (PCB 138) and heptachlorobiphenyl (PCB 180). Swiss scientists have previously found comparable pollution patterns in Swiss alpine glacier lakes and have pointed out the possible danger to drinking water supplies. Apparently, major mountain ranges like the Andes form a natural barrier for those POPs that are distributed globally through the atmosphere. The Spanish-, German-, Chilean team of scientists arrived at the conclusion that the effect of high mountain ranges on air-borne distribution of pollutants has been underestimated. The scientists recommend that this effect, and the processes involved, be investigated further. Since high mountain regions can be inaccessible, or at least difficult to reach, environmental testing can be an enormous challenge or even a life-threatening adventure. Adding to the misery, pollut- Polychlorinated Biphenyls (PCBs) PCBs are a group of highly stable chlorinated aromatic hydrocarbons containing from one to ten chlorine atoms. A total of 209 different PCB compounds exist; these are normally referred to as congeners. The chemical frame of PCB molecules is formed by two phenyl rings that can rotate freely. The general chemical formula for PCBs is C12H(10-n)Cln, where n denotes the number of chlorine atoms (n=1-10). Internationally, the Ballschmiter nomenclature has prevailed, assigning a number up to 209 to each congeners. The order is decided by the number of chlorine atoms in the molecule as well as by their individual position. Such a numbering system is for example also used for polybrominated di-phenyl ethers (PBDEs). Even though they have been banned since the early 1980 s, due to their resistance to photolytic, biological and chemical decomposition, PCBs and polychlorinated terphenyls are still ubiquitous. They accumulate in the food chain and can cause significant health- and environmental problems. In case of fire or incomplete incineration, polychlorinated biphenyls and polychlorinated terphenyls can form toxic chlorinated dibenzofuranes. PCBs belong to the group of Persistent Organic Pollutants (POPs) that are classified as especially dangerous industrial chemicals by the United Nations Environment Programme (UNEP). PCB production, use and import were banned in Japan in The United States Congress banned PCB production in 1979, and in the Federal Republic of Germany, PCBs have not been produced since GERSTEL Solutions Worldwide No. 11 5

6 TDSA/TDS-GC/MS system used at the UFZ for automated desorption and analysis of up to 20 Twisters. As an alternative, the Thermal Desorption Unit (TDU) in combination with the MultiPurpose Sampler (MPS) performs automated analysis of up to 196 Twisters in one batch. The UFZ was responsible for analyzing the snow samples: While we needed at least one liter of snow to perform one analysis using conventional solvent-based extraction techniques, the solvent-free SBSE technique gave us the correct answer based on only a 40 milliliter sample, Dr. Peter Popp said. This was an invaluable difference: During expeditions at high altitudes, every gram counts. We could never have transported that many liters of snow. That is why we were delighted that just 40 milliliters of sample was sufficient, Roberto Quiroz from IIQAB, Barcelona added. Sampling in dizzying heights, analysis in the laboratory Quiroz took part in a 2003 rope party that took snow samples at 3500, 4300, 5000, 5800 and 6200 meters altitude on the eastern slopes of the Aconcagua. Samples were taken in 100 ml brown glass bottles and stored at -20 C until analyzed. In the laboratory, samples were melted at room temperature. A 40 ml sample of snow melt water was transferred to a 100 ml Erlenmeyer flask along with 10 ml of MeOH. The mixture was stirred for four hours using a Twister, whereby the PCBs in the sample were concentrated in the PDMS phase of the Twister. The Twister was then removed from the flask, dried, and placed in an empty thermal desorption glass tube. Ultra-low limits of determination and surprising results Thermal desorption of the Twister was performed using a Thermal Desorption System (TDS) equipped with a TDS A autosampler. If larger numbers of samples need to be analyzed, the GERSTEL Thermal Desorption Unit (TDU) in combination with the MultiPurpose Sampler (MPS) analyzes up to 196 Twisters in one batch. Twisters were thermally desorbed at 250 C for 10 minutes. Helium carrier gas flow at 100 ml/min was used to transfer analytes to the Cooled Injection System (CIS), where they were cryofocused at -20 C. The CIS was then heated to 250 C at a rate of 12 C/s. Analytes were transferred to the GC column in splitless mode, the split was reopened at 2.0 min. The separation was performed on an Agilent HP-5MS column (30 m, 0.25 mm ID, 0.25 µm film thickness) using the following temperature program: The GERSTEL Twister is small and easy to handle: For sensitive determination of PCBs in water, only a 40 ml sample is needed. An important fact, especially when samples have to be carried in your personal back pack at 6000 meter elevation, where every gram counts. For thermal desorption and GC/MS determination of the analytes, the Twister is placed in a sealed glass liner. Starting temperature: 70 C; 2 min hold; 15 C/min to 180 C; 10 min hold; 5 C/ min to 280 C; 10 min hold. A GC/MS system from Agilent Technologies was used (GC 6980/MSD 5973). Analytes were detected in SIM mode using two characteristic ions. Dr. Popp and the UFZ team analyzed the snow samples to determine a total of 25 PCBs. The SBSE-TDS-GC/MS method enabled recoveries between 85 and 93 percent on average. The limit of detection was 0.02 ng/l. In the Aconcaqua snow samples, the scientists mainly found the most persistent congeners PCB 138 and PCB 180, albeit in concentrations below 0.5 ng/l. This is a relatively low concentration compared with samples from other mountainous and cold regions in the world, leading Quiroz and his fellow scientists to conclude that the Southern Hemisphere is less polluted than the Northern Hemisphere. The presence of PCBs does prove, however, that these compounds are transported to and deposited in the Andes. The results of this research could gain additional relevance given the background of global climate change. If the glaciers were to melt or partially melt, the deposited chemical pollutants would be washed down-stream and could contaminate the local drinking water, says Roberto Quiroz. And it is not only in South America that glaciers play an important role as a source of drinking water and water for irrigation. Literature Chromatogram resulting from a snow sample taken at 6200 Meter elevation: Finding PCBs on the highest point of the Andes is proof of long-range atmospheric transport (LRAT) and accumulation of persistent organic pollutants (POPs) in the Southern hemisphere. Quiroz, R., Popp, P., Barra, R.: Analysis of PCB levels in snow from the Aconcagua Mountain (Southern Andes) using the stir bar sorptive extraction. Environmental Chemistry Letters 7 (2009), GERSTEL Solutions Worldwide No. 11

7 Food Safety Polyaromatic seafood platter? The oil well disaster in the Gulf of Mexico could have wide-ranging consequences for the environment and potentially for the tens of thousands who make a living from delivering seafood to our plates. Closer to home, consumers are still pondering whether it is safe to put seafood on the menu. A simple answer is not easy to come by, but government and industry resources at many levels have been actively focusing on the issue. Analytical labs have been working overtime using cumbersome regulated methods while trying to find new and more productive ways to analyze the mountain of samples before them. As always, when we rise to a challenge, new and sometimes unexpected answers are found. This much seems certain, nobody can really tell how the marine biosphere will respond to the trauma - or to the treatment for that matter. Following the unprecedented oil spill in the Gulf of Mexico that lasted almost three months, the environment has had to contend with the two-pronged attack of crude oil and of chemicals added to the cocktail to disperse the black gold. But which traces will remain? - And will toxic compounds accumulate? - And where? These are among the questions being posed. And, as always, the main focus of attention is potential direct health effects to humans. The main interaction between man and the environment of the Gulf of Mexico is through the plentiful supply of seafood harvested there. There has been general agreement that pollutants could wind up in our food and, notably, that polyaromatic hydrocarbons (PAHs) could accumulate through the food chain and be served up in concentrated form on a seafood platter. If so, what could appropriate measures to counter the threat look like? The answer and first step has been to implement comprehensive controls. As it turns out, every answer gives rise to new questions: The official method used to determine PAH levels in seafood is NOAA NMFS-NWFSC-59, which relies on Accelerated Solvent Extraction (ASE), two separate evaporative concentration steps, liquid chromatography cleanup, and finally GC/MS analysis. Following this method means that typically only one batch of 14 samples and associated standards Increasing sample throughput to 40 samples per day as opposed to 25 samples per week, is invaluable and will greatly assist response efforts aimed at determining seafood safety. Jeffery H. Moran, Public Health Laboratory, Arkansas, USA can be analyzed per week in most laboratories. When faced with a mountain of samples, initial estimates ran as high as 10,000 samples per month, more efficient methods will have to be found. Extraction technique of choice The authors of a recent publication set out to find a more efficient and practicable quanti- tative analysis method for PAHs in seafood, performing a study to determine if using a QuEChERS (Quick, Easy, Cheap, Effected, Rugged, and Safe) extraction method in conjunction with Stir Bar Sorptive Extraction (SBSE) could meet regulatory limits of detection and requirements established for precision and accuracy. SBSE has proven its worth for many challenging matrices over the past decade. A recent EPA Region 7 study has shown that SBSE is an effective and fast technique for trace PAH determination in water. The results of the study were presented in May 2010 at the 58th American Society for Mass Spectrometry (ASMS) Conference. SBSE relies on the GERSTEL Twister, a glass coated magnetic stir bar with an external layer of polydimethylsiloxane (PDMS). While stirring the sample, the Twister efficiently extracts organic compounds into the PDMS phase. Following the extraction step, the Twister is removed from the sample, quickly dried with a lint-free cloth and placed in a thermal desorption tube. The tube and twister are then placed in an autosampler tray, in which the tube is kept sealed to elim- GERSTEL Solutions Worldwide No. 11 7

8 Peak area analyte/peak area IS Extract of a shrimp sample (3 g), spiked with a mixture (2,5 ppb) of naphthalene (1), fluorene (2), phenanthrene (3), anthracene (4), fluoranthene (5), pyrene (6), benzo[a]anthracene (7), chrysene (8) and benzo[a]pyrene (9). Extract of an oyster sample (3 g), spiked with a mixture (2,5 ppb) of naphthalene (1), fluorene (2), phenanthrene (3), anthracene (4), fluoranthene (5), pyrene (6), benzo[a]anthracene (7), chrysene (8) and benzo[a]pyrene (9). Extract of a fish sample (3 g), spiked with a mixture (2,5 ppb) of naphthalene (1), fluorene (2), phenanthrene (3), anthracene (4), fluoranthene (5), pyrene (6), benzo[a]anthracene (7), chrysene (8) and benzo[a]pyrene (9). inate the risk of contamination. Thermal desorption of one or more Twisters is performed, for example, in the GERSTEL Thermal Desorption System (TDS) or Thermal Desorption Unit (TDU) and the analytes are transferred directly and quantitatively to the GC/MS system. Principle Compared with the NOAA method mentioned earlier, the QuEChERS- SBSE-GC/MS method is a revolution, no less; the QuEChERS method uses a single-step acetonitrile (ACN) extraction and liquid liquid partitioning based on salting out from the water in the sample using MgSO4. The original QuEChERS procedure for pesticides includes dispersive-solid-phase extraction (dspe) cleanup to remove organic acids, excess water, and other components with a combination of primary secondary amine (PSA) sorbent and MgSO4. However, this cleanup step provides no additional concentration factor making it difficult to achieve detection limits meeting the current requirements for PAH analysis. The procedure used in the work reported here includes using SBSE as a combined cleanup and concentration step, eliminating organic acids and other polar and high molecular weight matrix components and providing a substantial concentration factor to easily achieve the regulatory detection limits. In brief, 3 g of a homogenized seafood tissue sample in water is extracted with ACN in a 50 ml centrifuge tube followed by addition of 6.0 g MgSO4 and 1.5 g sodium acetate which is shaken and centrifuged. A portion of the ACN extract (upper layer) is added to a 10 ml vial along with 4 ml 0.1 M NaHCO3 and a GERSTEL Twister stir bar that is used to extract and concentrate the PAHs. The Twister is removed from the sample extract, rinsed with DI water to remove matrix residue, dried with a Authors / More information lint-free cloth, placed in a TDU tube, and the TDU tube is placed in the MultiPurpose Sampler (MPS) tray. From that point on, everything is automated. The Twister is thermally desorbed and analytes are transferred to the Cooled Injection System (CIS) GC inlet where they are cryofocused. Using a fast temperature program, the focused analytes are transferred in a narrow band from the CIS inlet to the GC column, providing the best possible basis for a clean GC separation and ultra-low limits of detection. The system used combined a GERSTEL MPS, TDU and CIS 4 with a GC/MS System from Agilent Technologies (GC 7890/MSD 5975). Using this method, at least 40 samples can be analyzed per day. Conclusion The scientists showed that QuECh- ERS and SBSE extraction is an excellent alternative to the currently used NOAA NMFS-NWFSC-59 method used for the determination of PAHs in seafood matrices. SBSE was able to outperform the NOAA method on multiple counts: 1) Efficient, easy, and conveniently automated, SBSE-GC/MS dramatically improves sample throughput, which is especially important when a large number of samples need to be analyzed or screened. 2) Even though the NOAA method relies on two evaporative analyte concentration steps and LC clean-up, QuEChERS-SBSE-GC/MS provides limits of detection that are a factor lower. Reducing the 1:10 split ratio used in the SBSE-GC/MS method would further improve detection limits. 3) The QuEChERS-SBSE-based method significantly reduces the amount of solvent needed. This saves cost, protects the environment, and reduces the amount of solvent in the laboratory air thereby improving occupational safety for laboratory staff. Concentration [ppb] Calibration curve for Benzo[a]pyrene determined in spiked oysters. d12-perylene was added as internal standard (IS) to the sample resulting in a concentration of 25 ppb IS in the sample. Further, the following deuterated internal standards were used: for the analytes naphthalene and fluorene: d8-naphthalene; for anthracene and phenanthrene: d10-phenanthrene; and for fluoranthene, pyrene, benz[a]anthracene and chrysene: d12- chrysene. Jackie Whitecavage, Jack R. Stuff and Edward A. Pfannkoch GERSTEL Inc., Linthicum, MD 21090, USA. Jeffery H. Moran Arkansas Public Health Laboratory, Little Rock, AR 72205, USA For more information, please visit our website ( applications.htm) to download the GERSTEL AppNotes 2010/6a and 2010/6b: High Throughput Method for the Determination of PAHs in Seafood by QuEChERS-SBSE-GC-MS. 8 GERSTEL Solutions Worldwide No. 11

9 Off Flavors in Wine: Corky Efficient and sensitive determination of TCA and other off-flavors When your premium wine tastes corky, it is little consolation that this is not caused by the natural cork material used to produce the classic wine stopper. Corkiness points to the presence of 2,4,6-trichloroanisol (TCA), the most well-known malodorous culprit. But other chemical suspects are at large that can equally cause the unpleasant musty, moldy off-odor assault to your nose, and these may not even be coming from the cork stopper. To ensure an efficient, reliable and sensitive determination of all corkiness-related off-flavor compounds, the DLR Mosel in Germany successfully turned to GC/MS combined with Stir Bar Sorptive Extraction (SBSE). You don t have to be a sommelier or wine expert to tell the difference between a perfect wine and a corky wine. 2,4,6-trichloroanisol (TCA) has an extremely low odor threshold. As little as a few nanograms per liter of air is enough to detect an unpleasant musty off-flavor. In water and wine it is a similar story with odor thresholds at 0.3 ng/l and 1.4 ng/l respectively, but that is only a theoretical value, says Horst Rudy from the Agricultural Service Center (DLR) of the Mosel wine region in Germany. After all, the laboratory manager explains, sensory perception is highly individual and very subjective: While one consumer may sense no problem even at much higher concentrations, another person s olfactory bulbs sets off the mal-odor alarm at concentration levels as low as 0.5 ng/l. In addition, several factors could influence sensory perception of the Horst Rudy off-flavors; among these are sweetness, alcohol content and grape type. Whoever wants to identify corky off-flavor compounds and track down their source has no choice but to use gas chromatogra- phy combined with mass selective detection (GC/MS), Horst Rudy points out. Barking up the wrong tree on the origins of Corkiness The usual suspect as a source of 2,4,6-TCA is the cork stopper made from the bark of the cork oak tree (Quercus suber). TCA is a microbial metab- GERSTEL Solutions Worldwide No. 11 9

10 olite, formed by methylation of trichlorophenol (TCP) that may have been applied to the bark as a pesticide. To suspect the cork stopper of introducing TCA to the wine is therefore only logical according to the wine expert, but when wine drinkers started experiencing corkiness in wines with modern polymerbased stoppers experts knew that they had been barking up the wrong tree. Over the course of the ensuing research projects, it was found that various compounds, mainly halogenated anisols, would give a musty, moldy note to the wine. These compounds could be formed from other chlorinated chemicals that are used for cleaning of wine production equipment or for treating wooden transport pallets or packaging material Until the end of the 1980 s, pentachlorophenol (PCP) was used as a fungicide to protect, for example wooden pallets from microbial decay. Among others byproducts, PCP contained 2,3,4,6-tetrachlorophenol (TCP), a compounds that is metabolized microbially to 2,3,4,6-tetrachloroanisol (2,3,4,6-TeCA, TeCA), which also causes corkiness in wine. 2,4,6-TCA Area TCA / concentration Area ISTD [ng/l] Calibration curve for 2,4,6-trichloroanisol (TCA): Limit of detection: 0.39 ng/l; Limit of determination: 0.79 ng/l 2,4,6-TBA Area TBA / concentration Area ISTD [ng/l] Calibration curve for 2,4,6-tribromoanisol (TBA): Limit of detection: 0.50 ng/l; Limit of determination: 1.0 ng/l Limit of Detection Odor thresholds 2,4,6-Trichloroanisole (TCA) ng/l ng/l 2,4,6-Tribromoanisole (TBA) 0.5 ng/l 3-8 ng/l 2,3,4,6-Tetrachloroanisole (TeCA) 1.1 ng/l 4-24 ng/l 2,4,6-Trichlorophenol (TCP) 1.4 ng/l 4000 ng/l 2,4,6-Tribromophenol (TBP) 1.6 ng/l Pentachlorophenol (PCA) 0.9 ng/l 4000 ng/l Limits of detection and odor thresholds of the corkiness-causing compounds determined using SBSE-GC/MS. to 2,4,6-tribromoanisol (2,4,6-TBA), a compound given the sensory attributes musty, earthy, and chemical with a smell of solvent. TBA is a corkiness causing compound of the first order, Horst Rudy points out. Chemical analysis and sensory evaluation complementary techniques SIM chromatogram of 1.0 ng/l TCA Corkiness-related off flavor compounds found in wine: 2,4,6-trichloroanisole (TCA [1]) and 2,4,6-tribromoanisole (TBA [2]). 1 SIM chromatogram of 2.4 ng/l TBA 2 In animal tests, PCP was found to be carcinogenic. In Germany, the use of PCP has been prohibited since PCP was substituted by 2,4,6-tribromophenol (TBP), a combined fungicide and flame retardant, which is often used to protect cardboard packaging, polymer materials, paints and coatings. As it turns out, microorganisms metabolize TBP File TCA [ng/l] Day Day Day Standard deviations under real laboratory conditions. A 1.5 L sample of water used to wash cork material was homogenized and ten separate aliquots were extracted using SBSE (GERSTEL Twister). GC/MS analyses were performed over three consecutive days. Mean value: 5.9 ng/l; standard deviation s = 1.26 ng/l; Minimum value 4.5, maximum value 8.5 ng/l. When the DLR Mosel is asked to determine the cause of a musty and moldy off flavor in a wine, sensory evaluation is only the first step in the process. While corky off-flavors are typically determined quite reliably, Horst Rudy says, TCA concentrations at or below the odor threshold often lead to a subtle and indefinable change in the wine flavor, not perceived as a corky flavor note. In such cases, chemical analysis is needed in order to prove that the wine is under the influence of TCA. To snoop out the source of the contamination, all aspects of the wine production and bottling process, as well as the entire production site environment, must be carefully investigated. Horst Rudy and his team deploy passive samplers based on Bentonite clay to pick up TCA traces. Passive samplers are easy to work with and they deliver valuable information such as a distribution profile enabling us to more accurately localize the source, says Mr. Rudy. As a general rule, the DLR does not restrict its GC/MS investigations to off-flavors that are perceived as corky. Among the targeted compounds are: 2,4,6-trichloroanisol (TCA), 2,4,6-tribromoanisol (TBA), 2,3,4,6-tetrachloroanisol (TeCA), 2,3,4,5,6-pentachloroanisol (PCA), as well as the TCA and TBA pre- 10 GERSTEL Solutions Worldwide No. 11

11 Step by step: How to extract odor active compounds from wine or water using the GERSTEL Twister 1 Instead of six hours per analysis, the Twister based analysis only requires 1.5 hours in order to determine the concentration of corkiness-related off flavor compounds. Multiple samples can be processed simultaneously. 2 cursors 2,4,6-trichlorophenol (TCP) and 2,4,6-tribromophenol (TBP), which are less odor-active. The presence and distribution of TCP and TBP can give valuable information as to the source of an off-flavor. To determine the identity and concentration of odor agents, cork stoppers are extracted for two hours in a 10 % ethanolwater mixture using sonication to speed up the process. The bentonite clay used for passive sampling is extracted in the same way. Subsequently, 100 ml of the Ethanol solution is extracted for one hour by Stir Bar Sorptive Extraction (SBSE) using a GERSTEL Twister (The bentonite should be allowed to precipitate before sampling is performed). The Twister is a glass-coated magnetic stir bar with an outer Polydimethylsiloxane (PDMS) layer. While the Twister stirs the sample, analytes are extracted and concentrated into the PDMS phase. Depending on the application and on the sample volume available, SBSE can be up to 1,000 times more sensitive than SPME due to both the significantly larger PDMS volume available and to the larger sample volumes extracted. Quantification in this work was performed using 2,4,6-trichloroanisol-D5 as internal standard. Phase Micro-Extraction (SPME) enabled the DLR to reduce the analysis time significantly, but the limits of detection achieved, for example 2.9 ng/l for TCA, meant that this technique was only of limited use. We have to reliably determine concentrations of odoractive compounds at their odor threshold levels, says Horst Rudy, and for this reason we started using SBSE and the GERSTEL Twister. SBSE is a fast and accurate extraction technique that enables the DLR laboratories to reach a detection limit of between 0.3 and 0.5 ng/l for TCA as per the DIN method and the analysis time has been reduced from 6 hours to 1.5 hours per sample and multiple samples can be processed in parallel for improved productivity. SBSE is extremely easy to perform: Following the extraction step, the Twister is removed from the sample, dried using a lint-free paper cloth and transferred to the autosampler tray. Up to 196 Twisters can be desorbed and analyzed by GC/MS in a single batch using the GERSTEL MPS and TDU directly mounted on a GC/MS system. The work reported in this article was performed using a GC 6890/MSD 5975 (Agilent Technologies) Fast and sensitive analysis using the GERSTEL Twister The multi-stage liquid-liquid extraction previously used by DLR Mosel was highly laborand cost intensive. Sometimes I spent all day in the laboratory and still only managed to analyze four samples, states Mr. Rudy. More modern analysis techniques, such as Solid Contact Horst Rudy DLR Mosel, Dept. of Viticulture and Oenology, Egbertstrasse 18-19, Trier, Germany, Phone +49 (0)651/ or -185, -186 Fax +49(0)651/ , horst.rudy@dlr.rlp.de Place the Twister in the sample (1). While stirring the sample, the Twister concentrates analytes in its PDMS phase (2). The Twister is removed from the sample (3), dried with a lint-free cloth (4) and placed in the MPS tray (5) for automated thermal desorption in the TDU (6). 6 GERSTEL Solutions Worldwide No

12 New Subsidiary Tan Surakanpinit GERSTEL on expansion course in South East Asia Supporting a growing market for automated GC/MS and LC/MS solutions: GERSTEL LLP, Singapore In order to support a growing customer base in South East Asia, GERSTEL has founded a wholly-owned subsidiary in Singapore: GERSTEL Limited Liability Partnership (LLP). GERSTEL already has subsidiaries in the U.S.A., Japan, Switzerland, and Brazil. GERSTEL is also represented in 70 other countries world-wide, by carefully selected and fully trained distributors. GERSTEL LLP will be run by Tan Surakanpinit. Ms. Surakanpinit was born in Thailand, where she studied Chemistry and later received her MBA. Ms. Surakanpinit brings extensive international experience in the chromatography laboratory instrumentation business into her new position. Prior to joining GERSTEL, she held a range of positions from Regional Sales & Business Development Manager to World-Wide Marketing Manager taking her to workplaces in Thailand, The Netherlands, the U.S.A. and Singapore. Ms. Surakanpinit s responsibilities will include supporting our distributors and developing new business opportunities in the Asia Pacific Territories, including Singapore, Malaysia, The Philippines, Taiwan, Vietnam, Thailand, Australia, and New Zealand. Contact GERSTEL LLP, Level 25, North Tower One Raffles Quay, Singapore Phone: Fax: sea@gerstel.com Multi-Desorption Mode TD Automated Multi-Desorption Mode is available for the GERSTEL Thermal Desorption System (TDS) and GERSTEL Thermal Desorption Unit (TDU). Analytes from a number of sample extractions can be desorbed and concentrated into a single GC/MS run, significantly increasing sensitivity and reducing limits of detection. Multidesorption mode is activated by simple selection in the MAESTRO configuration editor. In the sequence table, desorption of multiple adsorbent tubes or Twisters for every GC/MS run can then be specified. Individual tube numbers or ranges can be chosen freely. For SBSE analysis, peak areas have been shown to be proportional to the number of Twisters desorbed. 12 GERSTEL Solutions Worldwide No. 11

13 Flavor and Fragrance Analysis Put on the 1D/2D goggles... The more complex the sample and the wider the concentration range of analytes, the bigger the challenge for the chromatographer to get a clean separation and sharp peaks. One short-cut is to heart-cut the challenging part(s) of the chromatogram to a 2nd dimension to get a full set of separated peaks. The patented new Selectable 1D/2D- GC/MS system enables simple and flexible switching between one- and two-dimensional GC/MS analysis on a single GC/MS system. Determination of flavors and allergens in food, cosmetics and personal care products is certainly not a trivial matter. The matrix is often complex, sometimes requiring extensive sample clean-up and up to several sample preparation steps. Efficient automated sample preparation is a good first step on the way to getting reliable results, but even well prepared samples can produce forests of overlapping peaks making it a case of not being able to see the trees for the forest. When compound peaks overlap, or if a flavor emerges from the Olfactory Detection Port (ODP) without a detectable associated signal from the MS, multi-dimensional GC can be the solution that cuts through the thicket and provides clear, reliable answers where one dimensional GC can not. Until now, performing multidimensional GC analysis has required the use of a dedicated system with two GCs coupled to each other. Due to the extra cost, and to the often limited utilization in the sections are then transferred to the 2nd dimension column as soon as there is sufficient mass on column to reliably perform the determination. In order to speed up the analysis and eliminate interferences in the 2D chromatogram, the 1D column can be backflushed following the heart-cut(s) in case no furtem. It is, in short, a routine analysis system that offers heart-cutting, two-dimensional GC separation, and analyte concentration from multiple injections on demand. The MS detector is used in both dimensions to ensure clear and unequivocal peak identification. Additional detectors, such as a PFPD sulphur-selective detector can be added to the system without modifying the hardware. In simplified terms, the method of operation Figure 1. Schematic of the selectable 1D/2D-GC-MS system. Interesting sections of the standard 1D chromatogram can be heartcut for separation on the 2D column. Analytes can be cryofocused using a GERSTEL CryoTrap System (CTS) positioned between the 1D and 2D columns. Heart-cut fractions from multiple injections can be cryofocused and combined into one 2D-separation for enhanced sensitivity. The 1D and 2D chromatograms and olfactograms are acquired on the same MSD and ODP. laboratory, such solutions don t always provide the best return on investment (ROI). GERSTEL now offers a solution that can be used for routine analysis as well as for special challenges. The patented GERSTEL Selectable 1D/2D- GC/MS system is a flexible solution, based on a single standard GC/MS syscan be described as follows: When questions arise regarding a section of the standard onedimensional chromatogram, the section in question can be transferred to a 2nd dimension, i.e. a GC column with different polarity installed in a separate module in the same GC. The process of cutting a section of a chromatogram and introducing it to another column is called heart-cutting. The GC system can be used to determine analytes in either the 1st or the 2nd dimension in a flexible manner. Neither the GC run, nor analyte detection is interrupted during the run. Detection of the analytes that were transferred to the 2nd column is performed using the same detector(s) used for the 1st dimension: MSD, ODP, PFPD etc. etc. Should lower detection limits be required for the analyte in question, the system enables heart-cutting from multiple repeat injections combined with cryofocusing on a GER- STEL Cryo Trap System (CTS) of the sections that were cut. The cumulated GERSTEL Solutions Worldwide No

14 Figure 2. Stacked view TICs of the 1st dimension chromatogram (A) and the combined 1st and 2nd dimension chromatogram (B) that results from heart-cut from mins. Sample: 0.1 µg/ml bucchu ketone in water. Figure 3. Stacked view peach flavor sample TICs of the 1st dimension chromatogram (A) and the combined 1st and 2nd dimension chromatogram that results from a heart-cut from mins. (B). The absence of peaks in the 1D chromatogram during the heart-cut period is evidence that eluting compounds are transferred efficiently to the 2D column. Figure 4. Stacked view peach flavor sample TICs resulting from the desorption of 1 (A) and 5 (B) Twisters respectively. Heart-cuts were performed between the 1st and 2nd column from mins. The combined 1st and 2nd dimension (1D/2D) chromatograms are shown. In the bottom trace, the initial 1D part is from the 5th Twister desorption whereas the 2D chromatogram part results from accumulated heart-cuts from all five 1D runs. Analytes were focused on the GERSTEL CryoTrap System (CTS) between the 1D and 2D columns. ther compounds are deemed of interest. A schematic of the system is shown in figure 1. The GC columns used in the system are placed outside the GC oven in Low Thermal Mass (LTM) modules. The LTM technology enables fast heating and cooling for faster analysis as well as independent temperature programming for each column module. The standard GC oven is merely used as a heated chamber for pneumatic connectors and switching devices. Keeping the GC oven at a fixed temperature contributes to the excellent system stability seen in our work with the system so far: Connectors are not subjected to cycles of heating and cooling with the associated material expansion and contraction that can eventually result in system leaks. The analysis system and the sample preparation used To check the performance under everyday routine analysis conditions, the selectable 1D/2D-GC/MS-system was used to determine bucchu ketone, which is the main flavor compound in peach flavor and is also found in gin. Typical samples have complex matrices resulting in countless interfering peaks. Because of this, multidimensional separation is the best means of getting information from peaks that otherwise would be hidden when using only 1D separation. With the addition of the ODP, the technique also provides valuable olfactory information from compounds that many times are not detected by the MSD. The main components of the selectable 1D/2D-GC/MS system are as follows: A GC 6890 equipped with a GER- STEL Cooled Injection System (CIS 4 - PTV-type universal inlet); two Low Thermal Mass (LTM) column modules; 5975C InertXL MSD (both from Agilent Technologies); GERSTEL Thermal Desorption System (TDS) with TDS- A autosampler; as well as a GERSTEL CryoTrap System (CTS 2). Alternatively, a GERSTEL Thermal Desorption Unit (TDU) in combination with a Multi- Purpose Sampler (MPS) can be used instead of the TDS/TDS-A system. Stir Bar Sorptive Extraction (SBSE) was used to extract flavor compounds from both peach flavor and gin. SBSE is performed using the GERSTEL Twister, a glass encased magnetic stir bar coated with PDMS. While the Twister stirs the sample, analytes are efficiently absorbed in the PDMS phase. Different Twisters are available with Analytical conditions different phase volumes. Depending on the phase volume the analyte, and the sample volume SBSE can provide up to 1000 times better sensitivity than SPME. Successful implementation Samples were prepared for SBSE as follows: Peach flavor sample: The sample was spiked to a concentration of 1 µg/ml bucchu ketone. 200 µl aliquots were pipetted into 10 ml screw cap headspace vials containing 9.8 ml bottled water to achieve a concentration of 0.02 µg/ml bucchu ketone in 10 ml of solution. Gin sample: 0.5 ml aliquots of gin were pipetted into 10 ml screw cap headspace vials containing 4.5 ml bottled water. TDS KAS Pneumatics GC oven Column 1 (1D) CTS Column 2 (2D) MSD mode Splitless 30 C 60 C/min 250 C (5 min) Liner packed with glass wool Solvent venting (50 ml/min) Peach flavor: Split (10:1) Gin: Splitless -150 C 12 C/s 280 C (3 min) Constant pressure 250 C isothermal 10 m Rtx-5 (Restek), LTM configuration, 0.18 mm ID µm film thickness (d f ) Peach flavor: 40 C (1 min) 10 C/min 260 C (0.8 min) 100 C/min 40 C Gin: 40 C (1 min) 10 C/min 160 C (0.8 min) 140 C/min 300 C Peach flavor: -50 C (11.2 min) 20 C/s 240 C (2 min) Gin: -50 C (17 min) 20 C/s 240 C (2 min) 10 m DB-Wax (Agilent), LTM configuration, 0.18 mm ID, 0.18 µm film thickness (d f ) Peach flavor: 40 C (11.2 min) 20 C/min 230 C (1.5 min) 50 C/min 40 C Gin: 40 C (17 min) 10 C/min 210 C 170 C/min 40 C Full scan, amu 14 GERSTEL Solutions Worldwide No. 11

15 Figure 6. TIC of gin sample: Combined 1st and 2nd dimension chromatogram that results from a heart-cut from mins. Figure 7. Stacked view gin sample TICs resulting from the desorption of 1 (A) and 5 Twisters (B) respectively. Heart-cuts were performed between the 1st and 2nd column from mins. The combined 1st and 2nd dimension (1D/2D) chromatograms are shown. In the bottom trace, the initial 1D part is from the 5th Twister desorption whereas the 2D chromatogram part results from accumulated heart-cuts from all five 1D runs. Figure 5. 1st dimension TIC of gin sample. A conditioned Twister was added to each vial. The vials were screw capped, and the samples stirred at room temperature for 1hr. Twisters were rinsed with water, dabbed dry, and placed into separate conditioned TDS tubes. The TDS tubes were finally placed in the TDS-A autosampler for analysis. All further steps were performed automatically. As a first step, the Twisters that had been used to extract the standard solutions were analyzed. Bucchu ketone was found in the retention time window between 10 and 11 minutes in the 1st dimension (1D) chromatogram. Performing a heart-cut of this time window resulted in a 2nd dimension (2D) chromatogram with a number of peaks that could not have been separated in the 1st dimension (figure 2). The same approach was used for the peach flavor sample: A heart cut was performed of the retention time window from 10 to 11 minutes. The co-eluting compounds that were transferred to the 2nd dimension were separated on the 2D column and identified. The 2nd dimension separation can follow either immediately after the heart-cut period or when the complete 1D separation has been finalized. The chromatograms from the two separations are acquired sequentially using the same MSD and combined into one GC/MS chromatogram. To ensure that late eluting analytes from the 1D column do not interfere with the 2D column chromatogram, the 1D column can be backflushed. In the case of the peach flavor sample, 1D column backflush was not necessary, since no compounds from the 1D column co-eluted with the compounds separated on the 2D column (figure 3). In case the 2D column separation doesn t yield satisfactory answers due to lack of sensitivity it is possible to perform heart-cuts from multiple injections and to concentrate the transferred compounds by cryofocusing before releasing the combined fractions to the 2D column performing a single separation and compound determination. To investigate the effectiveness of this approach, we cryofocused and then transferred five heart-cut fractions to the 2D column and compared the resulting chromatogram with one obtained from a single heart-cut fraction. The resulting chromatograms are shown in figure 4. Sharp peaks and excellent separation are obtained even after extended multi-step cryofocusing and the bucchu ketone signal is increased by a factor of 5.6 as can be seen in table 1. This result clearly shows the efficiency of the selectable 1D/2D-GC/MS system. Peak Area 1 Twister 1,535,403 5 Twisters 8,587,702 Table 1: Peak area for bucchu ketone as a function of number of twisters The analysis of gin using the Selectable 1D/2D-GC/MS system provided highly satisfactory results, similar to the results for peach flavor mentioned above. To determine the bucchu ketone level in a gin sample, a heart-cut was taken from the 1D chromatogram (Figure 5) between 9.36 and minutes and the fraction transferred to the 2D column. Transferring heart-cut fractions from 5 separate injections and cryofocusing these for a single 2D run resulted in a significant increase in sensitivity as can be seen in figure 7. Conclusion Selectable 1D/2D-GC/MS has been used successfully in flavor and fragrance analysis, both for food, beverage, body care, and cosmetic products. In addition to flavors, offflavors are an important application area for the 1D/2D technology. Off-flavors often need to be tracked down and determined both in the products themselves and in the packaging used and often the concentrations involved are at ultra-trace levels. The 1D/2D system presented here provides the analyst with a powerful and comprehensive tool consisting of different polarity columns for multi-dimensional separation of a wide range of compounds even in complex matrices. Further the added capability to concentrate flavor compounds from multiple injections is extremely helpful when tracking down off-flavors with low odor thresholds. Since the complete solution is built into a single standard GC/MS system, investment costs remain very reasonable. Further, the heart-cut fraction can be analyzed on the 2nd dimension column using the same MSD. Additional detection possibilities such as a PFPD or an Olfactory Detection Port (ODP) can be integrated and used without adding complexity to the operation of the system. Unlike standard multi-dimensional GC/MS systems, the 1D/2D system uses the MSD as monitoring detector for the 1D separation as well, ensuring that heart-cut sections are correctly chosen for the compounds in question and providing much additional information on the sample in general. Our experience after approximately two years is that the 1D/2D system is a rugged and reliable system for routine 1D analysis and that it is easily switched to 2D mode when additional separation power is needed. The GERSTEL MAESTRO software provides easy and convenient set-up by mouse-click of the entire system from one integrated method and one integrated sequence table. Authors Nobuo Ochiai and Kikuo Sasamoto, GERSTEL K.K., , Nakane, Meguro-ku, Tokyo , Japan John R. Stuff and Jacqueline A. Whitecavage, GERSTEL, Inc., 701 Digital Dr. Suite J, Linthicum, MD 21090, USA GERSTEL Solutions Worldwide No

16 Efficient flavor profiling of beverages that contain involatile matrix See the big picture - and every little detail Direct injection for gas chromatographic profiling of alcoholic beverages is usually preferable, but when these contain significant amounts of non-volatile material, pre-treatment is typically required to avoid both inlet and column contamination. This consideration applies in particular to products aged for extended periods in wooden barrels and especially products containing added sugar, as volatile artifacts from sugar decomposition in the hot injection port can also complicate the chromatogram. In this paper a combination of static and dynamic headspace analysis is described for routine profiling of both abundant and trace compounds in alcoholic beverages containing dry extract. Both techniques are performed using one combined analytical instrument and for both techniques the only sample preparation required is dilution of the sample in a headspace vial. Introduction Commercial distilled spirits are complex mixtures of flavor compounds in a dominant ethanol-water matrix [1,2]. These compounds originate from the combined production processes of raw material extraction, fermentation, distillation, and in many cases, ageing in oak barrels. Except for some low volatility compounds originating from wood lignin breakdown during ageing, the majority of flavor compounds in distilled spirits are amenable to gas chromatographic analysis. The matrix composition of distilled spirits is relatively clean and so direct injection without time-consuming sample preparation is possible. Abundant compounds at high mg/l levels can be quantified by simple split injection with flame ionization detection [3,4]. Additional compounds at low mg/l levels (higher esters and acids) can also be assayed by direct injection of 5-10 μl using a PTV injector for both removal of solvent and enrichment of compounds in the liner. This can be extended to μl injections for even lower detection limits, but in this case sample introduction must avoid overloading of the injection port liner and subsequent sample loss through the split vent. Speed programmed injection is necessary and recoveries depend on complex interactions between many related sample and instrumental parameters [5]. How- 16 GERSTEL Solutions Worldwide No. 11

17 Figure 1. GERSTEL MPS 2 with DHS mounted on an Agilent Technologies 7890 GC. ever, there are many commercial alcoholic beverages which can contain relatively substantial amounts of non-volatile material, and for which direct injection techniques may not be suitable. Fruit spirits and liquors can contain high amounts of added sugar, and very old brandies and whiskies etc. may contain higher than usual amounts of polyphenolic material from wood ageing. Without frequent liner exchange nonvolatile material will accumulate and contaminate both inlet system and column. Added sugar in such products also degrades in the hot inlet to produce artifacts which complicates chromatograms. In these cases there are additional techniques available which can avoid the unwanted effects of non-volatile material. These can be summarized as solid phase micro-extraction (SPME), stir bar sorptive extraction (SBSE) and headspace sorptive extraction (HSSE), static (HSS) and dynamic headspace sampling (DHS). All these techniques have many well documented applications in the literature [6-11]. With SPME a choice of sorbent materials is available but only limited sorbent volumes can be accommodated on the fiber. SBSE and HSSE can use much greater volumes of sorbent material, but this is almost always exclusively apolar polydimethylsiloxane. Headspace application could have the advantage that results may reflect more the actual sensory properties of the product analyzed. Static headspace with intermediate adsorbent trapping was applied to spirit drinks containing dry extract for analysis of the principal abundant secondary alcohols and esters [7]. Automated dynamic headspace using replaceable adsorbent traps was used to profile volatile compounds in beer [12]. In this paper we describe the sequential application of static and dynamic headspace to profiling both abundant and trace compounds in an aged whiskey. Maximum sensitivity for each mode is achieved by using a PTV injector in solvent vent mode where the liner can also act as a cold trap. Use of a short 0.15 mm I.D. apolar capillary column with a phase ratio of 19 allows fast analysis with excellent separation of both abundant and trace compounds. All operations for both modes of analysis are amenable to total automation for unattended sequence operation. GERSTEL Solutions Worldwide No. 11 Figure 2. Schematic view of the DHS process. No. Compound Figure 3. Static headspace chromatogram of an aged whiskey, a listing of compounds is shown in table 1. Figure 4. Dynamic headspace chromatogram of an aged whiskey, a listing of compounds is shown in table 1. 1 Propanol 2 Ethyl acetate 3 Isobutanol 4 3-Methyl butanal 5 2-Methyl butanal 6 1-Butanol 7 1,1-Diethoxy methane 8 Propionic acid ethyl ester 9 n-propyl acetate 10 3-Methyl-1-butanol 11 2-Methyl-1-butanol 12 Isobutyric acid ethyl ester 13 Isobutyl acetate 14 Butyric acid ethyl ester 15 Butyric acid 2&3-methyl-ethyl ester 16 Isobutyraldehyde diethyl acetate 17 Isoamyl acetate 18 2-Methyl-1-butyl acetate 19 Butyraldehyde diethyl acetal 20 Acetaldehyde ethyl amyl acetal 21 Hexanoic acid ethyl ester 22 Hexyl acetate 23 Heptanoic acid ethyl ester 24 Nonanal 25 ß-Phenyl ethyl alcohol 26 Octanoic acid 27 Octanoic acid ethyl ester 28 Decanal 29 ß-Phenyl ethyl acetate 30 Nonanoic acid ethyl ester 31 Decanoic acid 32 Ethyl trans-4 decenoate 33 Decanoic acid ethyl ester 34 Octanoic acid 3-methyl- butyl ester 35 1-Ethyl propyl octanoate 36 Capric acid isobutyl ester 37 Dodecanoic acid 38 Decanoic acid ethyl ester 39 Pentadecanoic acid 3-methyl-butyl ester 40 Pentadecanoic acid 2-methyl-butyl ester 41 Tetradecanoic acid ethyl ester 42 Ethyl-9-hexadecenoate 43 Hexadecanoic acid ethyl ester Table 1. Compound identification. 17

18 Experimental Analyses were performed using a 7890 GC equipped with a 5975 Mass Selective Detector (Agilent Technologies), Thermal Desorption Unit (TDU, GERSTEL), PTV inlet (CIS 4, GERSTEL) and MPS 2 with headspace and DHS option (GERSTEL) as shown in figure 1. Analysis conditions static headspace Trap: Tenax TA MPS: 60 C incubation temperature (10 min) 2.5 ml injection volume Analysis conditions dynamic headspace DHS Trap: Tenax TA DHS: 30 C trap temperature 60 C incubation temperature (10 min) 50 ml purge volume 10 ml/min purge flow 10 ml dry volume 5 ml/min dry flow TDU: solvent venting 20 C (1 min); 720 C/min; 110 C (1 min); 720 C/min; 300 C (3 min) Analysis conditions Cooled Injection System (CIS 4) CIS: Tenax TA liner, solvent vent (60 ml/min) at 0 kpa. Splitless (2 min) 20 C (0.2 min); 10 C/s; 300 C (5 min) Column: 25 m CP-SIL 5CB (Varian) di = 0.15 mm df = 2.0 μm Pneumatics: He, constant flow = 0.5 ml/min Oven: 40 C (10 min); 10 C/min; 300 C (6 min) MSD: Scan, amu Aqueous and high water content samples can often be problematic for headspace analysis. The presence of water vapor in the headspace above the sample can lead to poor precision. Operating the PTV inlet in solvent vent mode using a Tenax-filled liner significantly reduces the amount of water transferred to the analytical column. The GERSTEL Dynamic Headspace System (DHS) is an option for the MultiPurpose Sampler (MPS) which enables dynamic purging of the headspace above a sample. Analytes in the purged headspace are trapped onto a 2 cm sorbent bed in a compact glass tube, an optional dry purge step allows reduction of water content. The thermal desorption tube is then placed into the Thermal Desorption Unit (TDU) and thermally desorbed into the pre-cooled CIS 4 inlet, where the analytes are cryofocused to improve peak shape before introduction into the column. Applying the solvent vent mode in the TDU before transfer of analytes to the CIS provides an additional venting step of e.g. fusel alcohols. Figure 2 shows a schematic of the trapping and desorption process. Sample Preparation. No sample preparation other than transferring the samples into empty 10 ml screw cap headspace vials is necessary. Results and discussion Figure 3 shows a typical trace obtained using the headspace approach. The fusel or higher alcohols together with ethyl acetate and the principal straight chain fatty acid esters up to dodecanoic acid ethyl ester dominate the chromatogram. Interesting also in the initial elution space are clear peaks for important trace aldehydes, ethyl esters and acetals. Of particular importance are the ethyl esters of short chain fatty acids, called fruit esters due to their pleasant aromas. Pungent aldehydes and their sweet acetals with various alcohols can also affect perceived aroma. Figure 4 in turn shows the chromatogram obtained when the same sample is injected after dynamic headspace stripping. Analytes up to the C5 alcohols have been partially vented in the TDU since their elution in the chromatogram would give only limited information due to chromatographic crowding, but now much more compound detail is apparent in the remaining elution space. Many interesting esters of both straight and branched chain higher esters are visible and it is even possible to profile some acids. Nonanal and Decanal have been reported previously in beer, wine and cognac, and both are used in the flavor and fragrance business. Both injection modes are very reproducible and do not normally require use of internal standards. Conclusion A combination of static and dynamic headspace techniques offers a useful complimentary approach for profiling major and minor components in alcoholic beverages, especially those with substantial levels of dissolved solids. All constituent parts of each analysis are automated using the described instrumentation and no off-line sample preparation is required. Authors Kevin Mac Namara, Frank McGuigan Irish Distillers-Pernod Ricard, Midleton Distillery, Midleton, Cork, Ireland Andreas Hoffmann GERSTEL GmbH & Co. KG, Eberhard-Gerstel-Platz 1, Mülheim an der Ruhr, Germany REFERENCES [1] Aroma of Beer, Wine and Distilled Beverages, L. Nykänen, H. Suomalainen, Eds. Akademie-Verlag. Berlin (1983). [2] R. de Rijke, R. ter Heide, in Flavour of Distilled Beverages; J. Piggott Ed.; Ellis Horwood: Chichester (1983) 192. [3] K. Mac Namara, J. High Res. Chrom. 7 (1984) 641 [4] R. Madera, B. Suárez Valles, J. Chrom. Sci. 45 (2007) 428 [5] J. Staniewski, J. Rijks, J. Chrom. A 623 (1992) [6] A. Zalacain, J. Marín, G.L. Alonso, M.R. Salinas, Talanta 71 (2007) [7] K. Schulz, J. Dressler, E-M. Sohnius, D.W. Lachenmeier, J. Chrom. A 1145 (2007) [8] J.C.R. Demyttenaere, J.L. Sánchez Martínez, M.J. Téllez Valdés, R. Verhé, P. Sandra, Proceedings of the 25th ISCC, Riva del Garda, Italy, (2002). [9] P. Salvadeo, R. Boggia, F. Evangelisti, P. Zunin, Food Chem., 105 (2007) 1228 [10] B. Tienpont, F. David, C. Bicchi, P. Sandra, J. Microcol. Sep. 12(11) (2002) [11] C. Bicchi, C. Cordero, E. Liberto, P. Rubiolo, B. Sgorbini, P. Sandra, J. Chrom. A 1071 (2005) [12] J.R. Stuff, J.A. Whitecavage, A. Hoffmann, Gerstel Application Note AN/2008/4 18 GERSTEL Solutions Worldwide No. 11

19 Food Safety So long, troublemakers I The QuEChERS method may be a recent arrival on the scene, but it is conquering the world. QuEChERS provides fast and reasonably priced extraction, enabling efficient determination of pesticide levels in agricultural samples. GERSTEL application chemists have used automated Disposable Pipette Extraction (DPX), a miniaturized dispersive SPE technique, combined with GC/MS to optimize the determination of pesticides in QuEChERS extracts. Interfering matrix compounds can be chased off quite easily - without laborious sample preparation. Pesticides have long helped provide ample, affordable, and safe food supplies for billions of people across the globe. Even so, constant vigilance is needed in order to protect the environment and consumers from the consequences of improper application of pesticides to plants and crops. When it comes to food safety, the necessary first step is always to find efficient ways of controlling the quality of our food on a large scale in our globalized economy. Just the pesticides that can legally be used represent a list of hundreds of compounds with widely different characteristics. Multimethods are required, spanning both liquid chromatography (HPLC) and gas chromatography (GC) combined with Mass Spectrometry (MS). In theory, the analytical chemist can track down pretty much every pesticide known to man. In practice, the right sample preparation is critical if one wants to achieve accurate results; and it had better be automated, we re talking about a big job. In just a few years, the QuEChERS method (Quick, Easy, Cheap, Efficient, Rugged, and Safe) has become the method of choice for extracting toxins from a variety of foods. Initially, QuEChERS was developed as a fast and inexpensive method to extract pesticides from various, mainly plant-based matrices. Validation studies have proven that the QuEChERS method results in good recovery and low standard deviation for a wide range of pesticides. Furthermore, the QuEChERS method is much less laborintensive and requires much less solvent than previously used methods. A wide range of pesticides can be extracted. In many laboratories, QuEChERS has caused a veritable productivity boom. QuEChERS extracts the analytes and more... Every solution results in new, unexpected and interesting challenges and there is a price to pay for going QuEChERS: Fruit and vegetable extracts produced using the QuEChERS method contain large amounts of matrix residue. But quick and dirty is fine if we can get rid of the dirt afterwards. There are two ways to accomplish this: Clean up the extract or use analytical instruments that can handle samples with matrix residue. If we take a separate look at each of these alternatives, further clean-up of QuEChERS extracts is typically performed using manual dispersive solid phase extraction (SPE) followed by centrifugation to remove solids. These steps are not easily automated, but the same clean-up effect can be accomplished using Disposable Pipette Extraction (DPX), a dispersive SPE technique that is fully automated. In this article, examples are presented, which show that The GERSTEL MultiPurpose Sampler (MPS) PrepStation enables combined DPX extraction and sample introduction to the GC. GERSTEL Solutions Worldwide No

20 Spinach extract Orange extract without clean-up clean-up with DPX-Qg without clean-up clean-up with DPX-Q clean-up with DPX-Qg Spinach and orange extracts before and after DPX clean-up. Schematic diagram of the DPX clean-up. DPX is an attractive and efficient alternative for clean-up of spinach and orange extracts. Should the analyst not want to perform further clean-up of such extracts prior to GC/ MS analysis, the only remedy is to replace the GC inlet liner at regular intervals. Liner exchange is normally a time-consuming Full scan chromatograms of the spinach extract before (A) and after (B) DPX clean-up. SIM chromatogram after DPX clean-up of spinach extract spiked to a concentration of 200 ppb with a standard pesticide mixture. task, but GERSTEL s Automated Liner EXchange (ALEX) performs Liner EXchange automatically, enabling the analysis of samples with undissolved sample matrix. Matrix build-up has negative consequences especially for the GC/MS system: If raw QuEChERS extracts are injected directly into the GC, residue will accumulate in the inlet. This build-up will lead to compound loss by adsorption on active surfaces and increased variability, negatively impacting the results. In combination with the MultiPurpose Sampler (MPS), ALEX performs automated liner exchange at user-defined intervals. Disposable Pipette Extraction (DPX DPX is an SPE technique that relies not on packed adsorbents in standard cartridges, but on adsorbent powder placed inside disposable pipette tips. In the case of spinach and orange extracts, graphitized Carbon Black was used among other adsorbents (DPX Qg-tips, as specified in DIN EN 15662). Plant colorants, such as chlorophyll, and free acids were successfully removed. The transport adapter at the top and a frit at the bottom help contain adsorbent and sample inside the pipette tip while enabling highly efficient airbubble induced mixing. The transport adapter also serves the dual purpose of allowing the MPS to get a grip on the cartridge in order to transport it and to introduce the syringe needle into the cartridge for liquid transfer. The DPX process is clever yet simple: The MPS picks up a DPX tip from the tray. Depending on the method, the adsorbent can be washed with a suitable solvent, which is taken from a solvent reservoir. The solvent can either be aspirated into the tip from below or added to the top using the autosampler syringe. A 500 µl sample of the extract in question was aspirated into the tip. Extracts had been spiked with organochlorine- and organophosphorous pesticide standard mixtures at different concentration levels. Samples were aspirated into the DPX tip from below, which means they were never in contact with the syringe needle or piston. There is no sample-to-sample cross contamination or carry-over said Carlos Gil, Manager, Analytical Services at GER- STEL Headquarters, while adding: Since DPX is a dispersive SPE technique, the extraction efficiency is not influenced by the flow path or the flow rate through the adsorbent, making the technique highly rugged and reliable. Once the sample has entered the DPX tip, the syringe pulls air through the tip and the sample from below. The liquid suspension undergoes highly efficient turbulent mixing leading to optimal contact between the phases and highly efficient and fast extraction. The efficiency of the cleanup is clearly demonstrated by the fact that the final spinach extract is almost completely colorless, says Carlos Gil. The extraction takes place in less than two minutes. Then the cleaned QuEChERS extract is then transferred directly to a clean autosampler vial for analysis or to undergo further liquid sample preparation steps prior to the analysis as needed. The used pipette tip is discarded. As soon as the prepared sample has been introduced to the GC system, a clean pipette tip is picked up and the next sample prepared. Analysis and sample preparation are performed in parallel, ensuring best possible utilization and return on investment for the entire instrument set-up, says Carlos Gil. 20 GERSTEL Solutions Worldwide No. 11

21 The power of DPX - conclusion Apart from the visible removal of spinach and orange matrix, the analysis results bear testament to the efficiency of the DPX process. Carlos Gil: The results were convincing, we had excellent recovery of the organochlorine- and organophosphorous pesticides that were determined in the study. The relative standard deviation (n=3) was under 10 % both for the extract spiked at 20 ppb and for the extract spiked at 200 ppb. Average recoveries were 119 % for the orange sample and 91 % for the spinach. The study proved that automated DPX is useful for second stage clean-up of QuEChERS extracts prior to GC/MS analysis. The DPX tips efficiently removed interfering matrix material, improving overall system reliability and productivity, and reducing the need for maintenance since there was less residue build-up in the GC/MS system. Method parameters The analysis was performed on a GC 7890 / MSD 5975C GC/MS system (Agilent Technologies) configured with a GERSTEL Cooled Injection System (CIS) PTV-type inlet and a GERSTEL MultiPurpose Sampler (MPS) sample preparation robot fitted with a 10 µl syringe for liquid injection. Analysis parameters CIS 4: splitless 25 C; 12 C/s; 280 C (3 min) Column: 30 m DB5-MS (Agilent) di = 0.25 mm; df = 0.25 µm Carrier gas: He, constant flow 1.0 ml/min GC oven: 60 C (1 min); 10 C/min; 300 C (3 min) Standards A standard mixture of organochlorine- and organophosphorous pesticides at a concentration of 1000 µg/l was prepared in Acetonitrile. Sample preparation For quantification purposes, fruit and vegetable extracts were spiked with diluted pesticide standards. (Concentrations: 20 µg/l and 200 µg/l in 500 µl extract). DPX extraction 1 ml QuEChERS tips from DPX-Labs, LLC. 500 µl of the fruit- or vegetable extract was automatically transferred to a vial by the MPS fitted with a 2.5 ml syringe. A 1 µl aliquot of the extract was introduced to the GC. More information The sequence table for automated DPX sample preparation is easily and quickly set up by mouse-click in the MAESTRO. Orange Spinach Analyte % Recovery % RSD % Recovery % RSD 20 ppb 200 ppb 20 ppb 200 ppb 20 ppb 200 ppb 20 ppb 200 ppb Dichlorvos Mevinphos Phorate α-bhc δ-bhc Diazinon Methyl Parathion Ronnel Aldrin Trichloronate Heptachlor Epoxide t-chlordane Prothiofos Dieldrin Endrin β-endosulfan Fensulfothion Sulprofos DDT Endrin Keton Average Percent recovery and relative standard deviation for the pesticides. Analyte Orange Spinach No DPX DPX No DPX DPX Dichlorvos Mevinphos Phorate α-bhc δ-bhc Diazinon Methyl Parathion Ronnel Aldrin Trichloronate Heptachlor Epoxide t-chlordane Prothiofos Dieldrin Endrin β-endosulfan Fensulfothion Sulprofos DDT Endrin Ketone Average Recovery of the pesticides with and without DPX clean-up (spiked to a concentration level of 200 ppb). GERSTEL Solutions Worldwide No

22 Automated QuEChERS extract clean-up for LC-MS/MS So long, troublemakers II LC/MS and GC/MS systems are increasingly confronted with QuEChERS extracts that have to be cleaned prior to determination of pesticide residues in order to avoid build-up of matrix residue in the analysis system. Automated QuEChERS extract clean-up, including vortexing, centrifugation, and filtration directly followed by LC-MS/MS analysis of the cleaned extract is demonstrated in this article. The QuEChERS (quick, easy, cheap, effective, rugged, and safe) sample extraction method offers food safety laboratories a novel method that is a genuine step forward. QuEChERS is now the basis for efficient monitoring of pesticides in an evergrowing range of foods. Still, the method is quite labor intensive with several manual steps such as shaking, centrifugation, and dispersive SPE. If the dispersive SPE clean-up step could be automated, laboratory productivity could be improved significantly. When using the automated QuEChERS clean-up procedure for challenging botanical samples, it can be difficult to reach the low limits of detection required in order to meet acceptance criteria for reporting the maximum residue levels (MRLs) as established by regulatory agencies. Automated QuEChERS clean-up of fruit and vegetable extracts combined with LC-MS/MS determination of pesticides has been reported previously. This study focuses on using a similar system to automate the second step of the QuEChERS procedure and introduce the cleaned extract directly to an LC-MS/MS system. The aim is to provide high throughput analysis for the confirmation of pesticide residues in botanical matrices. Automated QuEChERS extractions are performed using a QuEChERS dispersive SPE sorbent blend for fatty matrices. Experimental Stock solutions containing the pesticide compounds listed in Table 1 in acetonitrile were Figure 1. Representative Mass Chromatograms for low QC sample. prepared and provided by the FDA. Calibration standards and matrix matched standards were prepared by making appropriate dilutions of the pesticide stock solutions using mobile phase, blank hop extract, or blank ginseng extract resulting in the following concentrations: 0.5, 1, 2, 5, 10, 20, 50, 100, 200, 500, and 1000 ng/ml. Crude acetonitrile extracts of pesticide-fortified samples, incurred samples, and blank matrix samples based on both hops and ginseng root were prepared and provided by the FDA. These samples were generated using QuEChERS extraction salts for the DIN EN Method and the recommended sample preparation method supplied with the salts. All automated PrepSequences were performed using a MultiPurpose Sampler (MPS XL Dual Head) configured for QuEChERS- LC-MS/MS analysis. QuEChERS extract pretreatment: Pipette 1 ml of the acetonitrile extract obtained following the 1st centrifugation step of the QuEChERS sample preparation method into a 2 ml glass autosampler vial containing a sorbent from a dispersive SPE kit for fatty samples, AOAC. Place the sample onto a tray on the GER- STEL MPS XL Dual Head. Figure 5. shows a representative calibration curve resulting from automated preparation of neat standards. The calibration curves were shown to be linear from at least 1.00 to 200 ppb for the pesticides monitored, using a linear, 1/x regression method. Automated Q uec hers extract clean-up: Agitate the sample vial for 1 minute using the Anatune CF-100 centrifuge. Centrifuge the sample vial at 575 g for 3 minutes using the Anatune CF-100 centrifuge. Filter 500 μl of the resulting supernatant through a 0.45 μm GERSTEL format syringe filter. Combine 100 μl of the resulting filtrate with 400 μl of mobile phase A in a clean 2 ml vial. Agitate the sample vial using the Anatune CF-100 centrifuge for 30 seconds. Inject 2 μl into the LC-MS/MS system. Analysis conditions LC Mobile Phase: A - 5 mm ammonium formate in water with 0.01 % formic acid B 0.01 % formic acid in acetonitrile Gradient: Initial 94 % A / 6 % B 0.3 min 94 % A / 6 % B 14 min 5 % A / 95 % B 17 min 5 % A / 95 % B Pressure: 600 bar Flowrate: 500 μl/min Runtime: 17 min Post time: 2.5 min Column: 2.1 mm x 100 mm, 1.8 μm, Zorbax Eclipse+ C18 RRHT (Agilent) Oven: 55 C Injection volume: 2 μl Analysis conditions MS Operation: ESI+ mode ( Jet Stream) Time Filter Width: 0.04 min Scan Type: Dynamic MRM Delta EMV: 0 V Cycle Time: 660 ms Gas Temperature: 225 C Gas Flow (N2): 10 L/min Nebulizer pressure: 25 psi Sheath Gas (N2): 350 C 11 L/min Capillary voltage: 4500 V Nozzle Voltage: 500 V 22 GERSTEL Solutions Worldwide No. 11

23 Preparation of all standards was automated using the MPS XL Dual Head as follows: Transfer 100 μl of previously extracted matrix blank or 100 % acetonitrile to an empty 2 ml autosampler vial. Transfer 250 μl of mobile phase A to the vial. Transfer 150 μl of the respective standard stock solution to the vial. Agitate the vial using the Anatune CF-100 and centrifuge for 30 seconds. All analyses were performed using an Agilent 1290 HPLC, an Agilent 6460 Triple Quadrupole Mass Spectrometer with electrospray source and Jet Stream Option and a GERSTEL MPS XL autosampler configured with Active Wash Station. Sample injections were made using a 6 port (0.25 mm) Cheminert C2V injection valve fitted with a 2 μl stainless steel sample loop. The mass spectrometer acquisition parameters and respective quantifier/qualifier ion transitions were chosen using the pesticide database option available for the MassHunter B software. Table 1 provides a list of the more than 200 pesticides that were monitored using this single LC-MS/MS method. A retention time window value of 0.5 minute was used for each positive ion transition being monitored during the course of the dynamic MRM experiment. Results and discussion Figures 1-4 show representative overlay mass chromatograms resulting from QuEChERS extracts of pesticide-fortified samples. More than 200 different pesticides were successfully determined in botanical matrices using the automated QuEChERS- LC-MS/MS method. The total time required per sample to perform the QuECh- ERS extract clean-up was 15 minutes. This was shorter than the LC-MS/MS analysis run, enabling the MPS system to complete preparation of the next sample during the LC-MS/MS run for maximum sample throughput. 3-Hydroxycarbofuran Acephate Acetamiprid Acibenzolar-S-methyl Alanycarb Aldicarb Aldicarbsulfone Aldicarb sulfoxid Aspon Avermectin B1a Avermectin B1b Azadirachtin Azoxystrobin Benalaxyl Bendiocarb Benfuracarb Benoxacor Benthiavalicarb Benzoximate Bifenazate Bifenthrin Bitertanol Boscalid Bromuconazole-1 Bromuconazole-2 Bupirimate Buprofezin Butafenacil Butocarboxym Butoxycarboxim Cadusafos Carbaryl Carbendazim Carbetamid Carbofuran Carboxine Carfentrazone-ethyl Chlordimeform Chlorfenvinphos-beta Chlorfluazuron Chlorotoluron Chloroxuron Clethodim Clofentezine Clothianidin Coumaphos Cumyluron Cyanazine Cyanophos Cyazofamid Cycluron Cymoxanil Cyproconazole Cyprodinil Cyromazine d10-diazinon d6-dichlorvos d6-dimethoate d6-diuron d6-linuron d6-malathion Daimuron Dazomet Deltamethrin Diazinon Dichlorvos Dicrotophos Diethofencarb Difenoconazol Diflubenzuron Dimethenamid Dimethoat Dimethomorph A Dimethomorph B Dimoxystrobin Diniconazole Dinotefuran Dioxacarb Disulfoton Dithiopyr Diuron Dodemorph 1 Dodemorph 2 E-Fenpyroximate Emamectin B1a Emamectin B1b Epoxiconazole Eprinomectin B1a EPTC Esprocarb Ethidimuron Ethiofencarb Ethion Ethiprole Ethirimol Ethofumesate Ethoprop Etobenzanid Etofenprox Etoxazole Famoxadone Fenamidone Fenarimol Fenazaquin Fenbuconazol Fenhexamid Fenoxanil Fenoxycarb Fenpropathrin Fenpropimorph Fenuron Flonicamid Flucarbazone Fludioxinil Flufenacet Flufenoxuron Flumetsulam Flumioxazin Fluometuron Fluquinconazole Flusilazol Fluthiacet-methyl Flutolanil Flutriafol Forchlorfenuron Formetanate Fuberidazole Furalaxyl Furathiocarb Heptenophos Hexaconazol Hexafl umuron Hexythiazox Hydramethylnon Imazalil Imazapyr Imibenconazole Imidacloprid Indanofan Indoxacarb Ipconazole Iprovalicarb Isocarbamid Isofenfos Isopropalin Isoproturon Isoxaben Isoxafl utole Kresoxim-methyl Lactofen Leptophos Linuron Lufenuron Mandipropamid Mefenazet Mepanipyrim Mepronil Metalaxyl Metconazole Methabenzthiazuron Methamidophos Methiocarb Methomyl Methoprotryne Methoxifenozid Metobromuron Metribuzin Mevinphos Mexacarbate Molinate Monocrotophos Monolinuron Moxidectin Myclobutanil Neburon Nitenpyram Norflurazon Novaluron Nuarimol Omethoate Oxadixyl Oxamyl Paclobutrazol Penconazole Pencycuron Phenmedipham Picoxystrobin Piperonyl butoxide Pirimicarb Prochloraz Promecarb Prometon Prometryn Propachlor Propamocarb Propargite Propazine Propham Propiconazole Propoxur Pymetrozine Pyracarbolid Pyraclostrobin Pyridaben Pyrimethanil Pyriproxyfen Quinoxyfen Rotenone Sebuthylazine Secbumeton Siduron Simazine Simetryn Spinosyn A Spinosyn D Spirodiclofen Spiromesifen Spiroxamin Sulfentrazone Tebuconazole Tebufenozide Tebufenpyrad Tebuthiuron Tefl ubenzuron Temephos Terbumeton Terbutryn Terbutylazine Tetraconazole Tetramethrin cis Thiabendazole Thiacloprid Thiametoxam Thiazopyr Thidiazuron Thiobencarb Thiofanox Thiophanate-methyl Triadimefon Triadimenol Trichlamide Trichlorfon Tricyclazole Trifloxystrobin Triflumizole Table pesticides monitored using automated QuEChERS extract clean-up. Conclusion The study has demonstrated: Successful monitoring of more than 200 pesticides in botanical matrix samples using automated QuEChERS extract clean-up coupled with LC-MS/MS analysis using the Agilent 6460 Triple Quadrapole Mass Spectrometer. Automation of both the QuEChERS extract clean-up and the preparation of standards using the GERSTEL MPS XL Dual Head robotic sampler. The just-in-time sample preparation capability included in the MAESTRO software enables highly efficient QuEChERS extract clean-up and analysis. Authors Fred Foster & Virgil Settle GERSTEL, Inc., Linthicum, MD U.S.A. Paul Roberts, Anatune, Ltd., Cambridge, UK Peter Stone, Agilent Technologies, Santa Clara,CA, U.S.A. Joan Stevens, Agilent Technologies, Wilmington, DE, U.S.A. Jon Wong, Kai Zhang, US FDA, College Park, MD, U.S.A Further Information Figures 2 through 4 show representative overlay mass chromatograms of neat, hop matrix matched, and ginseng matrix matched calibration standards respectively at 10 ppb. The standards were prepared automatically by the MPS XL. Figure 3. Representative overlay mass chromatogram for a 10 ppb hop matrix matched standard. Figure 4. Representative overlay mass chromatogram for a 10 ppb ginseng matrix matched standard. GERSTEL Solutions Worldwide No

24 Novel automated Pyrolyzer for the GERSTEL TDU Pyrolyzer module for the GERSTEL Thermal Desorption Unit (TDU) enables highly flexible and efficient automated pyrolysis of solids and liquids at up to 1000 C. GERSTEL has further expanded the capabilities of the Thermal Desorption Unit (TDU) adding a new dimension to an already vast range of technologies supported by our compact thermal desorber. A cleverly designed pyrolysis accessory enables efficient and flexible automated pyrolysis of liquids and solids. If required, thermal desorption and pyrolysis of the same sample can be performed in sequence to obtain the maximum amount of information in the shortest possible time. Different sample holders and different pyrolysis and GC/MS methods can be used in one automated sequence for faster and simpler method development and the analyst can run a range of different sample types in one automated sequence. When combined with the GERSTEL MultiPurpose Sampler (MPS), up to 196 samples can be analyzed automatically in one batch. With just one method and one sequence table the analyst can set up the complete system including thermal desorption, pyrolysis, and the GC/MS runs. This reduces the risk of error and enables a highly efficient work-flow, while providing sensitive and reliable results. The initial thermal desorption can be performed at temperatures ranging from ambient to 350 C. Pyrolysis is performed at temperatures from 350 C to 1000 C. The temperature program can be varied from sample to sample. Heating rates range from 0.02 C/s to 100 C/s, which means that optimal analysis conditions can be chosen for each sample type and for every conceivable matrix. Slow heating can, for example, be used for TGA simulation. Pyrolysis breakdown products are transferred to the GC/MS system using the GERSTEL Cooled Injection System (CIS) PTV-type inlet. The CIS can be used either simply as a heated split interface or as an intermediate cryofocusing trap in order to focus volatile analytes for best possible separation and maximum information content. The valve-free liner-in-liner concept eliminates sample-to-sample carry-over and the TDU and CIS liners are heated over their entire lengths to ensure best possible recovery and minimal contamination. The platinum filament is connected at four different points providing extremely accurate temperature control as well as monitoring of the filament condition, thus ensuring reliable results at all times. Change over between standard TDU operation and pyrolysis operation is performed in less than ten minutes ensuring that the complete system including the GC/MS can be used flexibly and to the greatest possible benefit of the laboratory. GERSTEL online: Information on products, applications, events and downloads, as well as general information about GERSTEL and our customer focused solutions: and Imprint Published by GERSTEL GmbH & Co. KG Eberhard-Gerstel-Platz Mülheim an der Ruhr, Germany Editorial director Guido Deussing Uhlandstrasse Neuss, Germany guido.deussing@pressetextkom.de Scientific advisory board Dr. Eike Kleine-Benne eike_kleine-benne@gerstel.de Dr. Oliver Lerch oliver_lerch@gerstel.de Dr. Malte Reimold malte_reimold@gerstel.de Translation and editing Kaj Petersen kaj_petersen@gerstel.com Design Paura Design, Hagen, Germany ISSN / G L O B A L A N A L Y T I C A L S O L U T I O N S GERSTEL, Inc., USA sales@gerstelus.com GERSTEL BRASIL gerstel-brasil@gerstel.com GERSTEL GmbH & Co. KG, Germany gerstel@gerstel.com GERSTEL AG, Switzerland gerstel@ch.gerstel.com GERSTEL K.K., Japan info@gerstel.co.jp GERSTEL LLP, Singapore sea@gerstel.com Subject to change. GERSTEL, GRAPHPACK and TWISTER are registered trademarks of GERSTEL GmbH & Co. KG. Printed in Germany 0311 Copyright by GERSTEL GmbH & Co. KG