Flavour profiling of milk using HiSorb sorptive extraction and TD GC MS

Transcription

1 Application Brief Released: October Application Note Flavour profiling of milk using HiSorb sorptive extraction and TD GC MS This study shows that the wide range of volatile and semi-volatile organic compounds (VOCs and SVOCs) giving rise to the flavour of milk can be identified by high-capacity sorptive extraction using PDMS probes, with analysis by thermal desorption gas chromatography mass spectrometry (TD GC MS). Results and discussion VOCs and SVOCs in semi-skimmed milk were sampled by immersing a HiSorb PDMS probe in the sample, followed by agitation for hours at room temperature using the HiSorb Agitator, and direct desorption TD GC MS analysis of the probe. Figure shows the complex profile obtained, and Table lists a selection of the compounds identified. The analyte range achievable with this analytical system is evident from the variety of compounds found, which ranged from C to C 9 and included alkanes, aldehydes, alcohols, acids, esters, ketones and lactones, as well as other compounds with potential to affect the flavour profile. Lactones are particularly important flavour compounds in a variety of foods, and in this example four δ-lactones were identified. δ-octalactone (#) although present at trace levels and co-eluting with a much more abundant component, was confidently identified by employing spectral deconvolution (see inset). Abundance ( counts) Sulfur dioxide Acetone Acetic acid n-hexane Hydroxyacetone Heptan--one Hexanoic acid Phenol 9 Octanal Acetophenone Nonan--one Nonanal Octanoic acid Decanal Nonanoic acid δ-octalactone Undecan--one, -Isopropylidene bis(tetrahydrofuran) 9 n-decanoic acid Tridecan--one δ-decalactone,-di-tert-butylphenol Dodecanoic acid Pentadecan--one δ-dodecalactone Tetradecanoic acid Pentadecanoic acid,-dihydroxypropyl decanoate 9 δ-tetradecalactone Palmitoleic acid cis-hexadec-- enoic acid Hexadecanoic acid Oleic acid Octadecanoic acid A β-monoglyceride of myristic acid -Palmitoyl glycerol Figure : Flavour profile of semi-skimmed milk, obtained by HiSorb sorptive extraction and TD GC MS analysis. T: + () 9 F: + () E: enquiries@markes.com

2 Page δ-octalactone (C H O ) Sweet fatty coconut, with creamy dairy nuances. Abundance ( counts) δ-decalactone (C H O ) Sweet, creamy, milky, peachy, buttery. δ-dodecalactone (C H O ) Fatty, creamy, waxy, lactonic, oily rich, milky. δ-tetradecalactone (C H O ) Fatty, creamy, waxy, lactonic, oily rich, milky. Figure : EIC profile (m/z 99) giving an indication of the relative abundances of several lactones present in the semi-skimmed milk. To assess the relative concentrations of these lactones, Figure shows an extracted-ion chromatogram (EIC) at m/z 99, which is a principal fragment ion for these compounds. δ-dodecalactone (#) predominates within this group, and therefore could be judged to be a contributor to the flavour of this milk. In conclusion, this study has shown the ability of HiSorb sorptive extraction, combined with analysis by automated TD, to aid the rapid flavour profiling of milk. The high-capacity PDMS phase results in higher sample loadings than SPME methods, and (combined with Markes TD pre-concentration technology) offers greater sensitivity across a wider analyte range, in a single run. A further benefit is provided by the unique capability of Markes instruments to re-collect all split flows, allowing repeat analysis for sample security, method optimisation and characterisation by alternative detection methods. 9 Experimental Sample: Semi-skimmed milk was purchased from a local supermarket and diluted : with analytical-grade water. Sorptive extraction: Sample volume: Probe: Immersion: Agitator speed: TD: Instrument: TD tube: Direct desorption: Cold trap: Trap desorb: HiSorb probe and Agitator (Markes International) ml Part no. H-AXAAC- (for ml vials) hours at room temperature rpm TD-xr (Markes International) Stainless steel (part no. C-AXXX-) C to C (. min) with : outlet split, then C to C ( min) splitless General-purpose (part no. U-TGPH-S) C ( min) GC: Column: DB-, m. mm. µm Oven: C ( min), then C/min to C ( min) Column flow: Helium, ml/min Quadrupole MS: Scan mode: m/z Source: C T-line: C Background to HiSorb Markes International s HiSorb system allows highcapacity sorptive extraction from liquids and solids. Samples are placed inside standard ml or ml vials, sealed with a crimped HiSorb septum cap, and a metal-core PDMS HiSorb probe inserted into the vial for either immersive or headspace sampling. The vial and probe are agitated and heated using the HiSorb Agitator, and after this the probe is washed, dried, and inserted into a conventional TD tube for direct desorption and automated TD GC MS analysis. PDMS sleeve sorptively extracts VOCs and SVOCs Tip pierces PTFE seal of headspace vial septum Metal shaft of probe allows easy manipulation HiSorb has been developed with Welsh Government SMART Cymru funding. HiSorb and TD-xr are trademarks of Markes International. DB- is a trademark of Agilent Corporation. Applications were performed under the stated analytical conditions. Operation under different conditions, or with incompatible sample matrices, may impact the performance shown. T: + () 9 F: + () E: enquiries@markes.com AN

3 Application Brief Released: October Application Note Flavour profiling of filter coffee using HiSorb sorptive extraction and TD GC MS This study shows that the wide range of volatile and semi-volatile organic compounds (VOCs and SVOCs) giving rise to the flavour of coffee can be identified by high-capacity sorptive extraction using PDMS probes, with analysis by thermal desorption gas chromatography mass spectrometry (TD GC MS). Results and discussion VOCs and SVOCs in freshly-brewed Colombian filter coffee were sampled by immersing a HiSorb PDMS probe in the sample, followed by agitation for hour at C using the HiSorb Agitator, and direct desorption TD GC MS analysis of the probe. Figure shows the complex profile obtained, and some of the key components are indicated. The overall flavour and aroma of coffee results from the combined presence of chemicals from a number of classes, including hydrocarbons, aldehydes, acids, esters as well as sulfur- and nitrogen-containing compounds. A number of furans are found in this sample, which typically have have caramel-like odours, because they result from the pyrolysis of sugars. Nitrogen-containing compounds are also of particular importance to the aroma of roasted coffee, with pyridine, pyrazines, pyrroles and pyrazoles being found in this sample. However, pyrazines can be common in defective coffee beans, and some of them may contribute undesirable flavours. Abundance ( counts) 9 9 -Methylbutanal -Methylbutanal N-Nitrosodimethylamine Pyridine Methylpyrazine Furfural -Furanmethanol,-Dimethylpyrazine 9 -Acetylfuran Furfuryl hexanoate -Formyl--methylpyrrole trans-,-bis(hydroxymethyl) cyclohexane -(-Furylmethyl)-H-pyrrole -(-Furyl)but--en--one -Ethyl--methoxyphenol Difurfuryl ether -Methoxy--vinylphenol -Amino--phenylpyrazole 9 trans--(-furyl)-n-(-furylmethyl) methanimine -(n-butyl)furan Figure : Flavour profile of freshly-brewed Colombian coffee, obtained by HiSorb sorptive extraction and TD GC MS analysis. T: + () 9 F: + () E: enquiries@markes.com

4 Page In conclusion, this study has shown the ability of HiSorb sorptive extraction, combined with analysis by automated TD, to aid the rapid flavour profiling of coffee. The high-capacity PDMS phase results in higher sample loadings than SPME methods, and (combined with Markes TD pre-concentration technology) offers greater sensitivity across a wider analyte range, in a single run. A further benefit is provided by the unique capability of Markes instruments to re-collect all split flows, allowing repeat analysis for sample security, method optimisation and characterisation by alternative detection methods. Experimental Sample: Colombian ground coffee was brewed using a coffee machine according to the manufacturer s instructions, and the coffee allowed to cool to C. Sorptive extraction: Sample volume: Probe: Immersion: hour at C Agitator speed: rpm TD: Instrument: TD tube: Direct desorption: Cold trap: Trap desorb : HiSorb probe and Agitator (Markes International) ml Part no. H-AXAAC- (for ml vials) TD-xr (Markes International) Stainless steel (part no. C-AXXX-) C ( min) with : outlet split General-purpose (part no. U-TGPH-S) C ( min) GC: Column: DB-, m. mm. µm Oven: C ( min), then C/min to C ( min) Column flow: Helium, ml/min Quadrupole MS: Scan mode: m/z Source: C T-line: C Background to HiSorb Markes International s HiSorb system allows highcapacity sorptive extraction from liquids and solids. Samples are placed inside standard ml or ml vials, sealed with a crimped HiSorb septum cap, and a metal-core PDMS HiSorb probe inserted into the vial for either immersive or headspace sampling. The vial and probe are agitated and heated using the HiSorb Agitator, and after this the probe is washed, dried, and inserted into a conventional TD tube for direct desorption and automated TD GC MS analysis. PDMS sleeve sorptively extracts VOCs and SVOCs Tip pierces PTFE seal of headspace vial septum Metal shaft of probe allows easy manipulation HiSorb has been developed with Welsh Government SMART Cymru funding. HiSorb and TD-xr are trademarks of Markes International. DB- is a trademark of Agilent Corporation. Applications were performed under the stated analytical conditions. Operation under different conditions, or with incompatible sample matrices, may impact the performance shown. T: + () 9 F: + () E: enquiries@markes.com AN

5 Application Brief Released: October Application Note Flavour profiling of herbal infusions using HiSorb sorptive extraction and TD GC MS This study compares the flavour profiles of five herbal infusions, obtained by highcapacity sorptive extraction using PDMS probes, with analysis by thermal desorption gas chromatography mass spectrometry (TD GC MS). The ability of the system to sample analytes from a range of chemical classes and volatilities is demonstrated. Results and discussion VOCs and SVOCs in freshly-brewed herbal infusions were sampled by immersing a HiSorb PDMS probe in the sample, followed by agitation for hour at C using the HiSorb Agitator, and direct desorption TD GC MS analysis of the probe. Figure shows the profiles for each of the five infusions, and some of the key components are indicated. Abundance ( counts) Abundance ( counts) Abundance ( 9 counts) A Peppermint B Peppermint & nettle Monoterpenoids are key components of the aroma and flavour of mint products, and these feature prominently in the peppermint infusion (A). The peppermint & nettle infusion (B) is very similar, except for the loss of two C alcohols (#, #) and the addition of the norsesquiterpene cyprotene (#9). Pinenes, as well as terpineol and geraniol derivatives, are evident in the lemon & ginger infusion (C). Figure : Flavour profiles of five herbal infusions, obtained by HiSorb sorptive extraction and TD GC MS analysis (continued on next page). 9 C Lemon & ginger 9 Oct--en--ol Octan--ol Eucalyptol trans-sabinene hydrate Linalool cis-p-menthan--one Isomenthol Isothujol 9 Pulegone Carvone Isomenthol acetate Piperitone Thymol Eugenol Tricyclo[...(,)]dec--ene Mint furanone Spathulenol Viridiflorol 9 Cyprotene α-pinene α-citral β-pinene Anethole β-phellandrene Nerol acetate γ-terpinene Geranyl acetate cis-p-menthan--one α-curcurmene trans-p-menthan--one epi-sesquithujene α-terpinyl acetate β-cedrene Nerol β-copaen-α-ol 9 Geraniol 9 -(-Hydroxy- trans-verbenol -methoxyphenyl)- butan--one T: + () 9 F: + () E: enquiries@markes.com

6 Page The echinacea & raspberry infusion (D) has a complex profile that includes a number of aroma-active esters, while the chamomile & honey infusion (E) has a relatively simple profile. One component, commonly called cis-enyne spirodiether (#), is known as a constituent of chamomile essential oil. In conclusion, this study has shown the ability of HiSorb sorptive extraction, combined with analysis by automated TD, to aid the rapid characterisation of herbal infusions. The high-capacity PDMS phase results in higher sample loadings than SPME methods, and (combined with Markes TD pre-concentration technology) offers greater sensitivity across a wider analyte range, in a single run. A further benefit is provided by the unique capability of Markes instruments to re-collect all split flows, allowing repeat analysis for sample security, method optimisation and characterisation by alternative detection methods. Abundance ( counts) Abundance ( counts) E Chamomile & honey 9 D Echinacea & raspberry 9 -(Butylamino)ethanol α-terpineol Methyl -methylbutanoate Anethole Ethyl -methylbutanoate Triacetin Ethyl -methylbutanoate Methyl cinnamate Ethyl hexanoate α-ionone Sylvestrene trans-β-ionone Terpin--enyl acetate γ-decalactone Benzyl acetate -(p-methoxy- 9 cis-p-menthan--one phenyl)butan-- trans-p-menthan--one one -Acetyl--methylfuran cis-p-menthan--one trans-p-menthan--one -Phenylethyl tiglate -Methoxybenzaldehyde Eugenol -Methylnaphth--ol -Hexyldihydrofuran-(H)-one 9 α-bisabolol oxide B Isopropyl styryl ketone Bisabolol oxide A Herniarin (Z)--hexa-,-diynylidene-,9-dioxaspiro[.]non--ene Figure : Flavour profiles of five herbal infusions, obtained by HiSorb sorptive extraction and TD GC MS analysis (continued from previous page). Experimental Sample: The herbal infusions were brewed using freshly boiled water in accordance with the manufacturer s instructions, and allowed to cool to C. Sorptive extraction: Sample volume: Probe: Immersion: hour at C Agitator speed: rpm TD: TD tube: Direct desorption: Cold trap: Trap desorb: HiSorb probe and Agitator (Markes International) ml Part no. H-AXAAC- (for ml vials) TD-xr (Markes International) Stainless steel (part no. C-AXXX-) C to C ( min) with : outlet split General-purpose (U-TGPH-S) C ( min) GC: Column: DB-, m. mm. µm Oven: C ( min), then C/min to C ( min) Column flow: Helium, ml/min Quadrupole MS: Scan mode: m/z Source: C T-line: C Background to HiSorb Markes International s HiSorb system allows highcapacity sorptive extraction from liquids and solids. Samples are placed inside standard ml or ml vials, sealed with a crimped HiSorb septum cap, and a metal-core PDMS HiSorb probe inserted into the vial for either immersive or headspace sampling. The vial and probe are agitated and heated using the HiSorb Agitator, and after this the probe is washed, dried, and inserted into a conventional TD tube for direct desorption and automated TD GC MS analysis. PDMS sleeve sorptively extracts VOCs and SVOCs Tip pierces PTFE seal of headspace vial septum Metal shaft of probe allows easy manipulation HiSorb has been developed with Welsh Government SMART Cymru funding. HiSorb and TD-xr are trademarks of Markes International. DB- is a trademark of Agilent Corporation. Applications were performed under the stated analytical conditions. Operation under different conditions, or with incompatible sample matrices, may impact the performance shown. T: + () 9 F: + () E: enquiries@markes.com AN

7 Application Brief Released: October Application Note Flavour profiling of alcoholic spirits using HiSorb sorptive extraction and TD GC MS This study shows that volatile and semi-volatile organic compounds (VOCs and SVOCs) at high and low levels in whisky and gin can be identified by high-capacity sorptive extraction using PDMS probes, with analysis by thermal desorption gas chromatography mass spectrometry (TD GC MS). Results and discussion VOCs and SVOCs in Scotch whisky and London gin were sampled by immersing a HiSorb PDMS probe in the sample, followed by agitation for hour at C using the HiSorb Agitator, and direct desorption TD GC MS analysis of the probe. Figure shows the analysis of the whisky sample, showing the ability of the HiSorb probe to sample compounds at high and low levels. The profile is dominated by medium-chain esters that likely contribute substantially to the flavour, while phenylethyl alcohol (#, which is known to impart a floral note) is also of interest. Methyl serinate,-diethoxypropane Styrene,-Diethoxy- -methylbutane Ethyl hexanoate Phenylethyl alcohol S Ethyl octanoate -Phenylethyl acetate 9 Ethyl decanoate Decanoic acid Ethyl dodecanoate Dodecanoic acid Dodecyl formate Ethyl tetradecanoate Hexadecyl acetate Ethyl hexadec-9-enoate Ethyl hexadecanoate Abundance ( counts) 9 9 Abundance ( counts) S Figure : Flavour profile of Scotch whisky, obtained by HiSorb sorptive extraction and TD GC MS analysis. The inset shows the full-scale plot. S = Siloxane. T: + () 9 F: + () E: enquiries@markes.com

8 Page α-pinene Sabinene β-myrcene β-pinene α-terpinene Limonene o-cymene γ-terpinene 9 Terpinolene Linalyl acetate Verbenyl ethyl ether Terpinen--ol Borneol acetate α-copaene Geranyl acetate α-guaiene γ-elemene Caryophyllene 9 Humulene δ-cadinene Abundance ( counts) Abundance ( counts) Figure : Flavour profile of London gin, obtained by HiSorb sorptive extraction and TD GC MS analysis. The inset shows the full-scale plot. Figure shows the analysis of the gin sample, and indicates the presence of a large number of monoterpenoids and sesquiterpenoids originating from the blend of botanicals used in its preparation. As with the whisky sample, both abundant compounds and trace-level components are sampled and analysed using this technique. In conclusion, this study has shown the ability of HiSorb sorptive extraction, combined with analysis by automated TD, Experimental Sample: Scotch whisky and London gin. Sorptive extraction: Sample volume: Probe: Immersion: hour at C Agitator speed: rpm TD: Instrument: TD tube: Direct desorption: Cold trap: Trap desorb : HiSorb probe and Agitator (Markes International) ml Part no. H-AXAAC- (for ml vials) TD-xr (Markes International) Stainless steel (part no. C-AXXX-) C ( min) with : outlet split General-purpose (part no. U-TGPH-S) C ( min) GC: Column: DB-ms, m. mm. µm Oven: C ( min), then C/min to C ( min) Column flow: Helium, ml/min Quadrupole MS: Scan mode: m/z Source: C T-line: C to aid the rapid flavour profiling of alcoholic spirits. The high-capacity PDMS phase results in higher sample loadings than SPME methods, and (combined with Markes TD pre-concentration technology) offers greater sensitivity across a wider analyte range, in a single run. A further benefit is provided by the unique capability of Markes instruments to re-collect all split flows, allowing repeat analysis for sample security, method optimisation and characterisation by alternative detection methods. Background to HiSorb Markes International s HiSorb system allows highcapacity sorptive extraction from liquids and solids. Samples are placed inside standard ml or ml vials, sealed with a crimped HiSorb septum cap, and a metal-core PDMS HiSorb probe inserted into the vial for either immersive or headspace sampling. The vial and probe are agitated and heated using the HiSorb Agitator, and after this the probe is washed, dried, and inserted into a conventional TD tube for direct desorption and automated TD GC MS analysis. PDMS sleeve sorptively extracts VOCs and SVOCs Tip pierces PTFE seal of headspace vial septum Metal shaft of probe allows easy manipulation HiSorb has been developed with Welsh Government SMART Cymru funding. HiSorb and TD-xr are trademarks of Markes International. DB-ms is a trademark of Agilent Corporation. Applications were performed under the stated analytical conditions. Operation under different conditions, or with incompatible sample matrices, may impact the performance shown. T: + () 9 F: + () E: enquiries@markes.com AN

9 Application Brief Released: October Application Note Flavour profiling of premium teas using HiSorb sorptive extraction and TD GC MS This study compares the flavour profiles of three premium teas, obtained by highcapacity sorptive extraction using PDMS probes, with analysis by thermal desorption gas chromatography mass spectrometry (TD GC MS). The ability of the system to sample analytes from a range of chemical classes and volatilities is demonstrated. Results and discussion VOCs and SVOCs in freshly-brewed Earl Grey, Vanilla Chai and Ceylon teas were sampled by immersing a HiSorb PDMS probe in the sample, followed by agitation for hour at C using the HiSorb Agitator, and direct desorption TD GC MS analysis of the probe. Figure shows the profiles for each of the three teas, and some of the key components are indicated. Abundance ( counts) Abundance ( counts) Abundance ( counts) 9 A Earl Grey S B Vanilla Chai 9 S 9 S C Ceylon S 9 Ethyl butanoate Hexanal Propylcyclopropane Styrene trans-hept--enal β-myrcene Benzaldehyde Octanal 9 Limonene -Propylfuran Eucalyptol trans,trans-hepta-,-dienal α-phellandrene Linalool -Pinanol trans-norbornan--ol Phenylethyl alcohol Estragole 9 Decanal Terpineol δ-terpineol acetate Methyl salicylate Linalyl acetate Geraniol Carvone Anethole Vinyl trans-cinnamate -Methylbenzofuran 9 trans-cinnamaldehyde Geranyl formate -Thujene Fragranyl acetate Eugenol Isoeugenol Coumarin -Methoxycinnamaldehyde a,a-dimethyloctahydronaphthalen-(h)-one Vanillylacetone Figure : Flavour profiles of three premium teas, obtained by HiSorb sorptive extraction and TD GC MS analysis. S = Siloxane. T: + () 9 F: + () E: enquiries@markes.com

10 Page All three teas show complex profiles with a large number of components at high and low levels. Characteristic components of the citrus fruit bergamot in the Earl Grey tea (A) are limonene (#9), linalool (#) and linalyl acetate (#), while the vanilla-derived compounds eucalyptol (#), anethole (#) and coumarin (#) are recovered from Vanilla Chai (B). The Ceylon tea (C) shows some similar compounds to the other samples, such as linalool (#) and eugenol (#), but also some unique compounds, including -propylfuran (#), phenylethyl alcohol (#) and trans-cinnamaldehyde (#9). In conclusion, this study has shown the ability of HiSorb sorptive extraction, combined with analysis by automated TD, to aid the rapid characterisation of teas. The high-capacity PDMS phase results in higher sample loadings than SPME methods, and (combined with Markes TD pre-concentration technology) offers greater sensitivity across a wider analyte range, in a single run. A further benefit is provided by the unique capability of Markes instruments to re-collect all split flows, allowing repeat analysis for sample security, method optimisation and characterisation by alternative detection methods. Experimental Sample: Each tea was brewed using freshly boiled water in accordance with the manufacturer s instructions, and allowed to cool to C. Sorptive extraction: Sample volume: Probe: Immersion: hour at C Agitator speed: rpm TD: TD tube: Direct desorption: Cold trap: Trap desorb: HiSorb probe and Agitator (Markes International) ml Part no. H-AXAAC- (for ml vials) TD-xr (Markes International) Stainless steel (part no. C-AXXX-) C to C ( min) with : outlet split General-purpose (U-TGPH-S) C ( min) GC: Column: DB-, m. mm. µm Oven: C ( min), then C/min to C ( min) Column flow: Helium, ml/min Quadrupole MS: Scan mode: m/z Source: C T-line: C Background to HiSorb Markes International s HiSorb system allows highcapacity sorptive extraction from liquids and solids. Samples are placed inside standard ml or ml vials, sealed with a crimped HiSorb septum cap, and a metal-core PDMS HiSorb probe inserted into the vial for either immersive or headspace sampling. The vial and probe are agitated and heated using the HiSorb Agitator, and after this the probe is washed, dried, and inserted into a conventional TD tube for direct desorption and automated TD GC MS analysis. PDMS sleeve sorptively extracts VOCs and SVOCs Tip pierces PTFE seal of headspace vial septum Metal shaft of probe allows easy manipulation HiSorb has been developed with Welsh Government SMART Cymru funding. HiSorb and TD-xr are trademarks of Markes International. DB- is a trademark of Agilent Corporation. Applications were performed under the stated analytical conditions. Operation under different conditions, or with incompatible sample matrices, may impact the performance shown. T: + () 9 F: + () E: enquiries@markes.com AN