Automated Photometry. Presented by Scott Tucker. Instruments

Transcription

1 Application Breakthroughs in Automated Photometry Presented by Scott Tucker Application Chemist, Lachat Instruments

2 Introduction Advantages of automated photometry FIAversus other techniques Lachat Application Breakthroughs

3 A comparison: Manual Chemistry Traditional manual chemistry methods can have several drawbacks: Can be very time consuming Operator and chemistry are both limiting factors Every manipulation of the sample will introduce errors Errors are very hard to control and will vary between samples

4 A comparison: Manual Chemistry Signal is measured at point of Steady State All reaction conditions must be exactly the same

5 Automation of Chemical Methods Automated Photometry provides advantages over traditional manual methods, including: Increased throughput / productivity Improved precision and accuracy Simplification of Data Quality Management, data integrity, and audit trails Decreased detection levels / sensitivity

6 Automation of Chemical Methods For colorimetric methods, there are three common types of automated photometric systems: Flow Injection Analysis (FIA) systems Discrete Analysis (DA) systems Segmented dflow Analysis (SFA) systems

7 What is Flow Injection Analysis? Flow Injection Analysis (FIA) is defined as the sequential insertion of discrete volumes of sample solution into an un segmented, continuously flowing stream, with subsequent detection of the analyte. The injected sample produces a zone which is transported to a continuously monitoring detector. The technique is performed by reproducibly manipulating sample and reagent zones in a flow under thermodynamically non equilibrated conditions. FIAwas developed by scientists who needed to process large numbers of samples but believed their Segmented Flow Analyzers decreased their productivity. FIA methodology, which is readily used with a wide variety of detection methods used in analytical chemistry, is a very flexible technique. Due to mixing characteristics within the tubing, there is no need for air bubbles to avoid dispersion.

8 What is Flow Injection Analysis? FIA analyses produce sharp peaks with fast rise and recovery times and a complete return to baseline between injections: NO CARRYOVER! Calibration for Zinc: R= Precision for Zinc: % RSD = 0.33% at 2.5 ppm No carryover at 500 ppm N as NO 3

9 What is Discrete Analysis (DA)? Discrete analyzers combine reagents and sample in a discrete location for colorimetric measurement with a filterphotometer through an automated process. This technology had been used extensively in the clinical market. It began to emerge in the environmental market in the past few years. Autosampler/pump combinationmoves moves samples, standards, & reagents to detector Autosampler/probe typically does mixing Heaters are not typical (no digestions allowed in system) User interface is a PC (is a black box system with only limited options to visually troubleshoot results)

10 How does FIA differ from Discrete Analysis? Discrete FIA Throughput decreases as number YES NO. Addition of reagents is of required reagents, or number of continuous and in line so the tests per samples increases number of reagents does not affect throughput. Requires chemistry to reach YES NO: resulting in significant endpoint time savings! Has issues with carryover YES, often due to the presence of NO: samples that fall within one analyte as a component of a the method range will not reagent for another chemistry when carryover. cuvettes are reuseable. Can be used in conjunction with inline sample preparation devices NO. Any needed sample preparation (Digestion, Distillation, etc.) must be done off line YES: Many proven in line sample preparation options available Uses area for peak quantitation Volume of sample analyzed is precisely controlled NO. Result is presented in numeric YES: More accurate, as an air form. spike or particle in the flow cell does not significantly change the result YES using syringe pump YES: By the use of an injection valve and sample loop of known volume

11 What is Segmented Flow Analysis (SFA) In Segmented Flow Analysis (SFA), a continuous stream of sample is divided by air bubbles into discrete segments in which chemical reactions occur. The continuous stream of liquid samples and reagents are combined and transported in tubing and mixing coils. An essential principle of the system is the introduction of air bubbles. The air bubbles segment each sample into discrete packets. Sample and reagent molecules drag on p g g the side of the tubing and transfer to the next segment = Carryover!

12 Carryover in an SFA analysis Peaks do not always return to baseline

13 How does FIA differ from SFA? In SFA, the chemical reaction must be at its endpoint prior to the measurement Each measurement takes longer to complete! The same is not true for FIA as both sample volume and residence time on the manifold are controlled. Because each sample is handled exactly thesame in thefiasystem, the chemistry does NOT have to reach its endpoint prior to measurement.

14 How does FIA differ from SFA? Requires bubbling and debubbling of fluid stream Requires the use of expensive glass tees and mixing coils SFA FIA YES NO: Uses a liquid carrier, usually DI water YES NO: Tubing is flexible, inexpensive, and easily replaced Requires chemistry to reach endpoint YES NO: resulting in significant time savings! Has issues with carryover (Memory YES NO: samples that fall within the Effect) under normal operating method range will not carryover. conditions Can be used in conjunction with inline sample preparation devices YES YES: Many proven options available Uses area for peak quantitation NO YES: More accurate, as an air spike or particle in the flow cell does not significantly change the result Volume of sample analyzed is precisely controlled NO YES: By the use of an injection valve and sample loop of known volume

15 APPLICATION BREAKTHROUGHS

16 It s all about the Applications Applications are Lachat s expertise, with over 400 active methods: Cover many ranges for a variety of matrices From common analytes (regulated parameters) to industry specific applications Custom requests have led to some more exotic methods as well: Free Amino Nitrogen in beer Hydroxy Proline in meat Nitrate in whey to name a few Presented today aresome of the newer, more innovative methods developed by Lachat Applications

17 Application Breakthroughs The following is an introductory on a few of Lachat s newer methods. These methods were developed to meet several objectives: Increase lab productivity Reduce costs through lower reagent consumption Provide a greener option.

18 Ultra High Throughput (UHT) Methods UHT Methods were developed to provide throughput of up to 125 samples per hour! Advantages: More efficient testing through reduced analysis time Significant reduction in reagent consumption Equivalent performance to other FIA methods (as well as to alternative techniques) Parameters: Ammonia* Orthophosphate* Total Phosphorus Cyanide Nitrate Nitrite* TKN TKP *available for waters and soil extract matrices

19 Ultra High Throughput (UHT) Methods Traditional vs. UHT methods Example of throughput and reagent consumption advantages: Traditional Method Throughput UHT Method Throughput Total Reagent Reduction Ammonia (Salicylate) A 80 samples / hr L 120 samples / hr 38% per sample Nitrate Nitrite Nitrite A 55 samples / hr R 120 samples / hr 24% per sample

20 Ultra Low Flow (ULF) Methods ULF Methods were developed to provide maximum efficiency in reagent usage Advantages: 70%+ reduction in reagent consumption vs. traditional Lachat methods Maintain efficient throughput of up to 60 samples per hour Equivalent performance to other FIA methods (as well as to alternative techniques)

21 Ultra Low Flow (ULF) Methods Traditional vs. ULF methods Example of reagent consumption advantages: Parameter Traditional Cyanide ULF Cyanide Traditional NO x ULF NO x Traditional Chloride ULF Chloride Methods A X A X J A A A Throughput 55 samples / hr 80 samples / hr 60 samples / hr 60 samples / hr 60 samples / hr 60 samples / hr Reagent use (ml per sample): Carrier DI water DI water Buffer NA Reagent Reagent NA NA Total Reagent Reduction 70% 62% 80% Available parameters: Ammonia, Chloride, Cyanide, Nitrate Nitrite, Nitrite, Orthophosphorus More to come soon!

22 Amperometric Detection for Cyanide Why use Amperometric Detection? Cyanide, detected electrochemically: Requires less reagents Less labor No hazardous pyridine or barbituric acid Existing, accepted methodologies for cyanide are not only labor intensive, but require the use of hazardous compounds, such as pyridine and barbituric acid, a controlled compound, regulated in the U.S. by the D.E.A.

23 Amperometric Detection for Cyanide There are a total of 5 cyanide methods, utilizing Amperometric Detection Method Number Range, µg CN /L Comments A Ligand Exchange; Approximately equivalent to Cyanide Amenable to Chlorination (CATC) B In line total CN, with UV Digestion. Recovers Ferricyanide and Ferrocyanide C Free Cyanide X Used to measure MicroDist Distillates for Total Cyanide WX Used to measure MicroDist Distillates for Weak Acid Dissociable Cyanide

24 Amperometric Cyanide & MICRO DIST Can use Lachat s patented MICRO DIST sample preparation technology with the Amp CN methods: MICRO DIST quantitatively scalesdown sample and reagent volumes. Key benefit is a disposable (or recyclable) polypropylene tube assembly (US Patents 5,022,967 and 5,304,287) Distillation is performed in 30 minutes for CN. 21 samples can be distilled at once! MICRO DIST can also be used in preparation for ammonia, sulfide, and phenol analyses.

25 Amperometric Cyanide & MICRO DIST The pre distilled d sample is mixed in line with dilute acid CN in solution becomes HCN (g) HCN (g) passes through a hydrophobic membrane and is trapped in dilute NaOH This stream is carried to the detector

26 Rapid Anions In addition to Flow Injection, Lachat Instruments also offers Ion Chromatographic (IC) methods A patented software algorithm called the Shared Peripheral System (SPS) enables operation of FIA and IC simultaneously and independently on the same instrument Alternatively, IC runs can be set to perform overnight, while hl FIA runs during the day!

27 Rapid Anions Mthd Method number E 00 1 Analyte Low Range, mg/l Mid Range, mg/l High Range, mg/l allows separation of the seven Bromide Chloride common anions in about 7 minutes Fluoride (dependent upon the ranges). Nitrate Nitrite Orthophosphate Sulfate Method is an Acceptable Version of EPA part A under NPDWR Chromatogram of calibration standard A Mid Range Time = 69minutes 6.9

28 UV Nitrate Reduction Lachat s newest Application Breakthrough Determination of Nitrate/Nitrite by photo induced reduction. 100% reduction efficiency NO toxic compounds Does not use cadmium, hydrazine, or vanadium Fast and cost effective PATENT PENDING

29 UV Nitrate Reduction UV Nitrate Rd Reduction methods, available soon! Method Number Matrix Range A Wt Waters 02t 0.2 to 20 mg N/L as NO 3 or NO A 2M KCl Soil Extracts 0.2 to 20 mg N/L as NO 3 or NO A Brackish/Seawater 0.05 to 5 mg N/L as NO 3 or NO to 20 mg N/L as NO 3 or NO 2 PATENT PENDING Method requires Lachat Inline Sample Preparation Module with UV lamp.

30 Automated Photometry Automation ti is a good solution for many labs lb requiring increased throughput while facing cost restraints t Flow Injection Analysis, a flexible and rapid technique, can be a good way to automate t when precision, accuracy, and speed are critical.

31 Custom Method Development Lachat Applications does custom method development FREE evaluations of method feasibility with the CPQ (Customer Profile Questionnaire) process Form available fromanylachat representative orat The custom work can be simple (range change) or complicated (current work on colorimetric arsenic method) Turnaround can be QUICK if needed and feasible

32 Lachat Applications does custom method development. Often our best ideas come from YOU! Thank you for your time and interest! Download this presentation and the current Lachat Methods List at com

33 Questions?

34 BACKUP SLIDES

35 Amperometric Cyanide & MICRO DIST Cyanide Spike Recoveries in Loveland, CO Tap Water Conclusion: Potassium, Ferro, Ferri and Nickel cyanide are recovered at levels greater than 96%. Sample ID Average spike recoveries Spike Level % Recovery (μg CN - /L) (μg CN - /L) Loveland Tap Water Loveland Tap Water KCN Loveland Tap Water Ferro-CN Loveland Tap Water Ferri-CN Loveland Tap Water K 2 Ni(CN)

36 Rapid Anions Sulfate Calibration

37 UV Nitrate Reduction Nitrate is quantitatively photo reduced to nitrite by the passage of the sample over a germicidal UV lamp. Nitrate in solutions are injected into a buffered carrier stream, which passes over a low pressure mercury lamp through PTFE tubing. The PTFE tubing is wound around the lamp and held onto the lamp with a reflective adhesive. Photo reducing the sample using UV light at 254 nm and utilizing i the EDTA compounds in the buffer, the reduction efficiency reaches 100%. PATENT PENDING Thenitrite (reduced nitrate plusoriginalnitrite) nitrite) isthen determined by diazotizing with sulfanilamide followed by coupling with N (1 naphthyl)ethylenediamine dihydrochloride. The resulting water soluble dye has magenta color, which is read at 540 nm.

38 UV Nitrate Reduction Waters method calibration PATENT PENDING

39 UV Nitrate Reduction PATENT PENDING Method Detection Limit for Nitrate using 0.10 N mg/l standard MDL= mg N/L Standard Deviation (s) = mg N/L, Mean (x) = mg N/L, Known value = 0.10 mg N/L

40 UV Nitrate Reduction PATENT PENDING Precision data for Nitrate using 10.0 mg N/L standard % RSD = Standard Deviation (s) = mg N/L, Mean (x) = mg N/L, Known value = mg N/L

41 UV Nitrate Reduction PATENT PENDING Nitrate to Nitrite concentration ratios

42 UV Nitrate Reduction Nitrogen compound ratio Concentration (mg/l) Nitrogen compound ratio Concentration (mg/l) 1 ppm NO ppm NO ppm NO ppm NO ppm NO ppm NO ppm NO ppm NO ppm NO ppm NO ppm NO ppm NO ppm NO ppm NO ppm NO ppm NO ppm NO ppm NO PATENT PENDING Nitrate to Nitrite concentration ratios

43 UV Nitrate Reduction PATENT PENDING Sample ID Unspiked conc (mg/l) Spiked conc (mg/l) Spiked amount (mg/l) % Recovery Loveland Tap % CA Tap % Milwaukee Tap %

44 UV Nitrate Reduction PATENT PENDING Sample ID Unspiked conc c (mg/l) Spiked conc c Spiked amount % Recovery e (mg/l) (mg/l) Lake Loveland % China Tap % Callegari Tap %

45 UV Nitrate Reduction PATENT PENDING Sample ID Unspiked conc c Spiked conc c Spiked amount % Recovery e (mg/l) (mg/l) (mg/l) Poudre River % LEP Effluent % Wastewater %

46 UV Nitrate Reduction PATENT PENDING Sample ID Unspiked conc (mg/l) Spiked conc Spiked amount (mg/l) % Recovery (mg/l) Loveland Effluent % Kodak Effluent % Batesville Effluent %

47 UV Nitrate Reduction PATENT PENDING Sample ID Unspiked conc c (mg/l) Spiked conc c (mg/l) Spiked amount (mg/l) % Recovery e Louisiana SW % California SW % Low Nutrient SW %

48 PATENT PENDING UV Nitrate Reduction

49 UV Nitrate Reduction Sample ID Unspiked conc Spiked conc (mg/l) Spiked amount (mg/l) % Recovery (mg/l) % % % % % % % PATENT PENDING % 2 M KCl Soil Extract Spikes Recoveries