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Analysis of PPB Level Volatile Chemicals using Static Preconcentration Introduction to Sampling and Analysis of Volatile Chemicals Comparison with other VOC Methods Air Analysis - Canister Methods Liquids and Solids - Large Volume Static Headspace (LVSH) Technique Other Applications Summary
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Analysis of PPB Level Volatile Chemicals using Static Preconcentration
Introduction to Sampling and Analysis of Volatile Chemicals Comparison with other VOC Methods Air Analysis - Canister Methods Liquids and Solids - Large Volume Static Headspace (LVSH) Technique Other Applications Summary Presentation Overview
GC/MS Detection Limits vs Headspace Sample Volume 1000 100 10 1 0.1 0.01 10-3 10-4 10-5 Loop Preconcentration PPM LOD Vol vs Conc. 0.001 0.01 0.1 1.0 10 100 1000 MINIMUM VOLUME REQUIRED (CC)
Classical VOC Sampling and Analysis • Air • Tedlar Bags • Adsorbent Tubes • Stainless Steel Canisters (EPA TO14, TO15) • Liquids & Solids • Purge and Trap • Static Headspace - Loop Injection
Classical VOC Sampling and Analysis • Air • Tedlar Bags • Adsorbent Tubes • Stainless Steel Canisters (EPA TO14, TO15) • Liquids & Solids • Purge and Trap • Static Headspace - Loop Injection • Large Volume Static Headspace
Volume Determination • Loop or Syringe Injection • Must equilibrate Sample to Atmospheric • Canister must usually be at positive pressures. • For Sample Volumes under 5 cc P • Mass Flow Time Integration • Canister Can be at Positive or Negative Pressure • Must verify leak free conditions before starting • MFC Downstream of trap reduces carryover • On-line Pressure Sensor monitors trap blockage • For Sample Volumes 10cc and larger MFC
Smaller Canisters (MiniCans) for Higher Concentration Samples
Canisters Tubes Chance For Volume Measurement Errors No Yes Traps Checked for Blank and Analyte Recovery Yes No Allow Repeat Analyses Yes No Chance for Post Cleaning Contamination Minor Yes Permits Sample Screening Yes No Allows Mild Trapping/Desorption Conditions Yes No to Maximize Yields Requires Power for Sampling No Yes Requires Conc. To be known Before Sampling No Yes Advantages Of Canisters Over Tubes
1320 32-Position Field Sampler and 1L MiniCans Bridging The Gap Between Tubes and Canisters
Six Sites Monitored with Just 2 Analyzers CS6 CS1 Centralized Lab Analyzers CS2 CS5 1 2 CS3 CS4
Are 1 Liter Canisters Large Enough? Instrument: 7100 Preconcentrator Application Detector Sample Vol. LOD PAMS FID 400cc 0.1 PPB(c) PAMS 5973 MS 400cc 0.05 PPB(v) Air Toxics 5973 MS 400cc 0.05 PPB(v) Air Toxics (SIMS) 5973 MS 400cc 0.005 PPB(v) Limited to Single Analysis - OK for Continuous Monitoring
Clean 21 (or 42) Canisters Simultaneously • 3 Batches a day equals 63 Canisters • Supports 7 sites with single 21 position manifold • Supports 14 sites with two 21 position manifolds
7032-LVSH / 7100 /5973 Large Volume Static Headspace Analyzer M3 SL I/O SL I/O M2 6 M1 GC MS 7100 7032-LVSH
7100 Heated Flow Path • Silonite tubing used throughout. • Complete heating of sample flow path. Easily accessed for trap and tubing replacement. • External Heaters outside each cryotrap 7100 Preconcentrator
7100 Water and CO2 Management Techniques MFC PUMP Loading Internal Standard N2, O2 Helium Carrier Helium To GC Focuser Glass Beads Tenax Sample Internal Standard Calibration Standard Sample Cryogen in
7100 Water and CO2 Management Techniques MFC PUMP Loading Calibration Standard Helium Carrier N2,O2 Helium To GC Focuser Glass Beads Tenax Sample Internal Standard Calibration Standard Cryogen in
7100 Water and CO2 Management Techniques MFC PUMP Loading Sample Helium Carrier N2, O2, Ar, CH4 Helium To GC CO2 H2O Focuser VOCs Glass Beads Tenax Sample Internal Standard Calibration Standard Cryogen in
7100 Water and CO2 Management Techniques MFC PUMP Flushing Traps Helium Carrier N2, O2, Ar, CH4 Helium To GC CO2 H2O Focuser VOCs Glass Beads Tenax Sample Internal Standard Calibration Standard Cryogen in
7100 Water and CO2 Management Techniques MFC PUMP Removing Water and CO2 CO2 Helium Carrier Helium To GC H2O VOCs Focuser Glass Beads Tenax Sample Internal Standard Calibration Standard Cryogen in
7100 Water and CO2 Management Techniques MFC PUMP Focusing Sample before Injection Helium Carrier Helium VOCs To GC VOCs Focuser Glass Beads Tenax Sample Internal Standard Calibration Standard Cryogen in
7100 Water and CO2 Management Techniques MFC PUMP H2O Post-Injection Bakeout Helium Carrier Helium To GC Focuser Glass Beads Tenax Sample Internal Standard Calibration Standard Cryogen in
Fast Injection and Proper Water Management Minimizes Tailing of Polar VOCs Column: HP1, 60m, 0.32mm ID, 1um film. Flow rate: 1.5 ccm Carrier: He
1 Week TO14 Stability Test 1 Liter MiniCan Concentration: 10 PPB Volume: 400cc Instrument: 7100/5973 GCMS Column: HP1, 60m, 0.32ID, 1um Column Start Temp: 35 deg. C
TO15 Precision Study using 7100 Preconcentrator and 5973 GCMS Data Compliments of: Columbia Analytical Jacksonville, Florida
TO15 Precision Study using 7100 Preconcentrator and 5973 GCMS Data Compliments of: Columbia Analytical Jacksonville, Florida
TO15 Precision Study using 7100 Preconcentrator and 5973 GCMS Data Compliments of: Columbia Analytical Jacksonville, Florida
C2-C10 GC/FID Analysis - Light Ends GC: 5890 Column: 60m, 0.32mmID, 1um, DB1 Preconc: MP&T, 400cc, 30ppbc Std GC Start Temp: -50 for 4 minutes
Vinyl Chloride 100x Calibration Curve usingVariable Volume / Single Standard Calibration
Multiple Preconcentration Options Depending on Target Compounds and Matrix (CO2, ETOH) Better Recovery of Thermally Labile Flavor and Odor Compounds: Strong Carbon Based Adsorbents are Avoided Inert, Silonite Tubing used Throughout Reduced Temperature Trapping Minimizes Sample Stress Advantages of 7100 Multi-Stage Preconcentration
Introduces 10-200cc of headspace to the 7100 Preconcentrator Accommodates solids and liquids Detection limits 100x lower than conventional loop injection headspace “See what you can smell” Large Volume Static Headspace Autosampler
LVSH Sample Platforms and Enclosures • Samples are placed in disposable vials, reducing potential for contamination of sample platforms. • Sample Platforms use quick connects, simplifying removal for oven bakeout.
Cheddar Cheese by LVSH/GCMS Cheddar Cheese, Brand A 100cc, LVSH 60m, HP1, 0.32mm ID, 1um 7032LVSH/7100/5973 Cheddar Cheese, Brand B 100cc, LVSH 60m, HP1, 0.32mm ID, 1um 7032LVSH/7100/5973 Toluene
Beer by LVSH/GCMS Beer, EtOH Removed 200cc, LVSH 60m, HP1, 0.32mm ID, 1um 7032LVSH/7100/5973 EtOH
Advantages of Large Volume Static Headspace (LVSH) over Purge and Trap • Cleaner. No aerosols or foaming to contaminate sample transfer lines • Better Recovery of Thermally Labile Flavor and Odor Compounds: • Strong carbon based adsorbents are avoided • Inert, Silonite tubing used throughout • Reduced temperature trapping minimizes sample stress, improving recovery and reducing artifact formation • Better matrix elimination using 3-stage trapping • More accurate determination of steady state distribution of chemicals in the sample headspace • Allows direct comparison of liquid, solid, and gas phase collected samples
Advantages of Large Volume Static Headspace (LVSH) over SPME • Less discrimination against light end compounds • LVSH is a closed system. Little chance of contamination with room air • Lower detection limits, especially for more volatile compounds • SPME cannot compare liquid, solid, and gas phase collected samples
100cc LVSH - Coke/Pepsi Challenge Coke Pepsi
Using LVSH to Determine Product Quality Markers in Fruits and Vegetables • Analysis of 100cc of Headspace allows detection of VOCs indicating condition of food products. • Monitoring changes in VOC ratios as food spoils allows quantitative evaluation of extent of spoilage. • Once specific “Markers” are determined, remote headspace techniques can be used to predict food condition and time until spoilage in storage containers and warehouses.