Section 9 Application Notes

Transcription

1 Section 9 Application tes Application tes 9-1

2 IX. Application tes As the Entech air system can be configured in a number of different ways, this section describes the operation from the perspective of your particular application. After properly configuring the hardware and software, refer to the relevant application in this section for detailed descriptions of method parameters. Flow Path Use the following diagram to trace the possible configurations of the system as a whole: the inlets, the modules, the GC and detector. Inlet Module 1 Module 2 Module3 Canisters Bags Tubes Loop Empty Bead / GC MS Injector Purge & Module Loop Inj. Moving from left to right, the highlighted boxes describe a flow path or hardware configuration. You will note that some applications like TO14 can have more than one hardware configuration, as many methods are performance based rather than procedurally based. Each application in this section will begin with this illustration of the more common system configurations. Application tes 9-2

3 IX. Application tes System Configuration Autosampler 1 Inlets CA-2 16 position ambient level tower manifold A 21 position MiniCan Autosampler A-B 21 position Tedlar Bag Autosampler A-L 21 position MiniCan Loop Autosampler Robotic Autosampler Purge & Autosampler 2 Autosampler 3 Purge & USB (SmartLab 2) PC LAN (GCMS) Application tes 9-3

4 IX. Application tes GC Modules Electronics Pneumatics 7100A Preconcentrator ing genic Tenax trap genic Bead trap genless Packed genic Bead Empty (Cold Dehydration) Hybrid Bead / Tenax (C2-C10 HCs) genless Packed Module Application tes 9-4

5 Index of Applications IX. Application tes EPA Method TO14 Canister Analysis Classical TO14 with Nafion Dryer water management analysis for non-polar Air Toxics (OBSOLETE - Nafion Dryer t Supported) EPA Method TO-14A / TO-15 Canister Analysis Advanced 3-stage preconcentration with Microscale Purge & water management for analysis of polar and non-polar VOC's. C2-C12 Hydrocarbon Analysis Analysis of hydrocarbons and non-polar VOC's using liquid nitrogen and a single column, single detector technique (GC/MS, GC/FID). C2-C12 Hydrocarbon Analysis (genless) Dual sorbent trap preconcentration with EPC controlled injection followed by dual column separation, dual FID detection. Operates without liquid nitrogen. EPA Methods TO-1 and TO-2 Analysis of 1/4" and 6mm sorbent tubes using single tube thermal desorber on the 7100 Preconcentrator. Analysis of Formaldehyde and VOCs in Indoor Air Silonite can Sampling; Preconcentration of Formaldehyde and VOCs using Cold Dehydration water management. Trace Analysis in High CO2 Matrices Preconcentration techniques capable of eliminating percent levels of CO2 without loss of VOC's and other contaminants. Trace Analysis of Reduced Sulfur Compounds Using Extended Cold Dehydration (ECTD) to monitor H2S, Mercaptans, and other reduced sulfur compounds down to sub ppb levels by GC/MS. Application tes 9-5

6 IX. Application tes Analysis of SVOCs using Heated Silonite Canister Analysis Recovery of C6-C20 Compounds using high temperature conditions and M1 dry purge water management Analysis of MVOCs for Mold Detection Analysis of Microbial VOCs from Methyl Furan to Geosmin using Heated MiniCans Large Volume Headspace Analysis Trace Analysis of Headspace above Liquid and Solid Samples 7032-L Loop Injection through the 7100A 3-Stage Concentrator Precise analysis of ppm level samples using loop injection with volume adjustment using method controlled splitting Automated Loop injection through 7100(A) ing Precise analysis of ppm level samples using loop injection with volume adjustment using method controlled splitting Integration of Purge & and 7100A VOC Preconcentrators Into a Single GC/MS For software selection of canister, water, or soil analysis. " Only" Small Volume Preconcentrations using Loops or Syringes For analysis of high concentration samples where optimum injection volumes are cc. BTEX Analysis (genless ) For analysis of benzene, toluene, ethylbenzene, and xylenes using a single Tenax trap without cryogen. Application tes 9-6

7 Application tes 9-7

8 TO15 Canister Analysis with Microscale Purge & Water Management Parameters Sample Concentration: 0.1 ppb ppb Sample Collection device: Silonite or SUMMA Canisters Sample Matrix: Ambient Air Water Management: Microscale Purge & Sample Pressure: -4 to 30 psig. Analyte List: (See T015 List) Analytical System Preconcentrator: Column: Detector: Scan Range: Solvent Delay: Temperatures deg C Event Description M1 M1 blkhd M2 M2 Blkhd M3 Concentration: Preheat: no Desorption: * Bakeout: Flows and Volumes Medium Preflush(sec) Flow Rate(sccm) Vol.(cc) Internal Standard Analytical Standard Sample Final sweep/purge flush M1-M2 Transfer A (3 stages)/7016ca-2 Autosampler DB1/DB5, 0.32mm ID, 60m 1µm film 5973 GC/MSD or Ion , 2-3Hz 0-6 min amu 2-3 Hz after 6 min. 0 minute Application Brief Application: Analysis of Polar and n-polar Air Toxics, including halogenated, aromatic, and oxgenated Volatile Organic Compounds (VOC'S). EPA Method: TO15, including many 1990 CAAA Hazardous Air Pollutants (HAP's) When to Use: For analysis of both polar and nonpolar VOC'S in ambient air, including methanol. Summary: Whole air samples are collected in Silonite coated or SUMMA passivated canisters. VOC'S are analyzed by GC/MS after preconcentrating cc cryogenically. Preconcentration System and Method Parameters Event Duration Zone Temp. Rotary Valves 100 GC Transfer Line 100 Manifold xfer Line 80 Autosampler rotary valve 80 Sample Ambient Event Min. M2 Desorb to er 3.5 Injection 2 Bakeout 10 er Bakeout (Event 3) 3 Wait time after Injection 25 (after last analyte elutes) Options Pressure Compensation - 14 CTD Second Temp - NA Max. Temp Below Setpoint: Mod deg. C Mod deg. C Extra M2 to M3 Transfer Time after start of Injection - 0 Min. * - t Controlled Directly. Inject Gas Heated Application tes 9-8

9 Inlet/Autosampler Module 1 Module 2 Module3 Canisters Bags Tubes/ Hi Flow Inj. Loop GC Injector Purge & Loop Inj. Nafion Dryer Empty Bead / Module System Hardware Configuration GC MS MP&T Water Management Microscale Purge and is analogous to Purge and used in water analysis, only on a much smaller scale. The air sample is first trapped cryogenically in MODULE 1 to concentrate the VOC's, CO 2, and H 2 O into roughly a 0.5cc volume. The glass bead trap is then heated to 10 deg. C and held there while slowly passing helium through the trap to transfer the VOC's to MODULE 2. The trap in MODULE 2 contains Tenax and is held at about -30 O C to retain the VOC's while letting CO 2 purge through. Sweeping the VOC's from the first to the second trap with only 40cc of sweep/ purge gas transfers only the amount of water capable of saturating 40cc of gas at room temperature. Benchtop mass spectrometers can handle this quantity of water quite easily (< 0.3µl). After the microscale purging and trapping, the second trap is heated and backflushed to the focusing trap to allow a rapid injection of the VOC's onto the analytical column. Since the water is left behind in the primary trap (and later baked out), this technique has no inherent sample volume limitation. Typical sample volumes using a 1/8" module 1 glass bead trap are cc. T015 Concentration Events using Microscale Purge & Moisture Management (3-Stage Preconcentration) 1. Wait for temperatures to reach setpoints 2. Optional wait for GC Ready 3. Cool Module 1 to trapping temperature 4. Preflush with Internal Standard 5. Internal Standard 6. Preflush with Analytical Standard 7. Analytical Standard 8. Preflush with Sample 9. Sample 10. Preflush with Helium Sweep/Purge gas 11. Helium Sweep/Purge gas 12. Preheat Module Transfer VOCs from M1 --> M2 14. Wait for GC Ready 15. Cool focusing trap 16. Optional M2 preheat 17. Transfer M2 --> M3 18. Heat M3, Inject, Start GC 19. Preflush with next sample 20. System bakeout 21. Wait time after injection Application tes 9-9

10 C2-C12 Hydrocarbon Analysis Using Liquid Nitrogen and Single Column Separation (GC/FID) Parameters Sample Concentration: Sample Collection device: Sample Matrix: Water Management: Sample Pressure: Analyte List: Analytical System Inlet: s Column: Detector: Scan Range: Solvent Delay: 0.1 ppbc ppbc SUMMA Cans or on-site Ambient Air 3-Stage MP&T -4 to 30 psig. (See C2-C12 Hydrocarbon List) 7100A (7016CA-2 optional) M1-GB/Tenax M2-Tenax DB1, 0.32mm ID, 60m, 1µm film 5890, 6890 GC/FID/ 5973 GCMS FID -5 Hz MS amu, 4 scans/sec, 8 min amu, 3 scans/sec 0 min Temperatures deg C Application Brief Application: Analysis of C2-C12 Hydrocarbons using a single column, single detector. EPA Method: When to Use: Summary: Ozone Precursers Title I 1990 CAAA To simplify the analytical approach when using $2-3 LN 2 per analysis is acceptable. Whole air samples are collected in Silonite or SUMMA canisters or analyzed on-site in real time cc are preconcentrated. Oven cooling to -50 O C is required to separate C2's. Preconcentration System and Method Parameters Event Description M1 M1 blkhd M2 M2 Blkhd M3 Concentration: Preheat: no Desorption: * Bakeout: Flows and Volumes Medium Preflush(sec) Flow Rate(sccm) Vol.(cc) Internal Standard Analytical Standard Sample Final sweep/purge flush M1-M2 Transfer Event Duration Zone Temp. Rotary Valves 100 GC Transfer Line 100 Manifold xfer Line 80 Autosampler rotary valve 80 Sample Ambient Event Min. M2 Desorb to er 2 Injection 2 Bakeout 5 er Bakeout (Event 3) 3 Wait time after Injection 40* * - After last analyte elutes Options Pressure Compensation - 14 CTD Second Temp - NA Max. Temp Below Setpoint: Mod deg. C Mod 2. 5 deg. C Extra M2 to M3 Transfer Time after start of Injection Min. Application tes 9-10

11 Inlet/Autosampler Module 1 Module 2 Module Canisters Bags Tubes/ Hi Flow Inj. Loop GC Injector Purge & Nafion Dryer Empty Bead 678 / Module System Hardware Configuration GC MS Loop Inj. Inlet/Autosampler Module 1 Module 2 Module Canisters 6789 Nafion 6789 Bags Dryer Tubes/ Hi Flow Inj. Loop GC Injector Purge & Loop Inj. Empty Bead / Module System Hardware Configuration GC MS C2 - C12 Hydrocarbon Analysis Analysis of C2-C12 hydrocarbons requires fine tuning of the 3-stage preconcentration procedure in order to accomodate this very large boiling point range. The standard glass bead trap normally used in module 1 is ineffective at reliably trapping ethane, ethene, and acetylene. To solve this, a hybrid glass bead / Tenax trap is used (pn ). By operating the M1 trap at -150 deg. C, the C3-C12 hydrocarbons are trapped efficiently on the glass bead half of the trap, while only the C2 hydrocarbons break through to the Tenax adsorbent. At -150 deg. C, Tenax will very effectly retain the C2 hydrocarbons. Back flushing of Module 1 to recover the sample during water/co2 management is still performed at 10 deg. C to minimize the amount of water transferred to module 2. However, to prevent migration of the heavier hydrocarbons to the Tenax in M1, module 1 is only preheated to -50 deg. C before starting the backflush. The C2 hydrocarbons are not retained by Tenax at 10 deg. C and are recovered completely during the room temperature backflush. Care must be taken during final focusing to avoid breakthrough and pre-injection of the C2 hydrocarbons. Set the M3 focuser to -170 deg. C instead of the normal -150 deg. C and focus for only 2 minutes. To improve the recovery of heavy hydrocarbons, go into VIEW/OPTIONS and choose an extra 2 minutes M2 to M3 transfer to help complete the recovery of heavy hydrocarbons from the Tenax trap. This option is found in software version 2.49 and later. Application tes 9-11

12 Hydrocarbon Concentration Events using Nafion Dryer or no Moisture Management (2-Stage Preconcentration) Procedure: /Cold Dehydration 1. Wait for temperatures to reach setpoints 2. Optional wait for GC Ready 3. Cool Module 1 to trapping temperature 4. Preflush with Internal Standard 5. Internal Standard 6. Preflush with Analytical Standard 7. Analytical Standard 8. Preflush with Sample 9. Sample 10. Preflush with Helium Sweep/Purge gas 11. Helium Sweep/Purge gas 12. Skip Step 13. Skip Step 14. Wait for GC Ready 15. Cool focusing trap 16. Optional M2 preheat 17. Transfer M2 --> M3 18. Heat M3, Inject, Start GC 19. Preflush with next sample 20. System bakeout 21. Wait time after injection Real Time Analysis Analysis of VOCs can be performed real time at a remote site with any configuration used for canisters or Tedlar bags. The system can be configured with a 7016CA-2 16-position autosampler allowing canisters collected on-site to be more easily analyzed during off-hours, if any. The 7100A can be operated in a real time mode where a start time is specified for each entry in the Sequence Table. The start times must be sequential and separated by more time than is necessary to complete a preconcentration and GC (GC/MS) analysis. Clicking on REAL activates this mode while choosing SPO cancels the real time scheduling. Operating in the real time mode also activates the canister sampler option for continuous sampling/analysis/evacuation using a single SUMMA canister. Evacuation times are entered using the REAL button. Application tes 9-12

13 Sample Introduction Sample Separation and Detection Field samples and standards Method gen Stage I Nafion Dryer Stage II Stage III genless Direct Direct sampling Integrated samples 1-6 hours without using LN2 Hybrid 4510 An economical alternative to time integrated sampling directly onto the cryotrap involves using a single canister to first collect the sample over 1, 3 or 8 hours. A sample can then be drawn out quickly (3-6 minutes) thereby using less cryogen than if the trap were kept cold for165 minutes(3 hour sampling). The Entech 7100A allows coordination of the canister filling and evacuation during unattended analysis. A cc/min mass flow controller is used to fill the canister at cc/min for minutes before the system begins drawing a sample. After a sample aliquot ( cc) is drawn out of the canister, the concentrator evacuates the canister for a pro- grammable period of time. A 6-8 minute evacuation at room temperature should be sufficient to remove 99+% of the canister contents when using a diaphragm pump capable of evacuating to 29.6" Hg or better. After evacuation, the 7100A returns to filling the canister at the selected flow rate to prepare for the next sampling event. Since the concentrator records the pressure of the sample before and after sampling, the actual canister pressure can be checked to verify that the initial canister pressure was approximately psia at the start of each sampling during unattended operation. Application tes 9-13

14 C2-C12 Hydrocarbon Analysis Using genless Preconcentration and Analysis (Dual Column, Dual FID) Parameters Sample Concentration: 0.1 ppbc ppbc Sample Collection device: SUMMA canisters or on-site Sample Matrix: Ambient Air Water Management: Dry Purge from M1 Sample Pressure: -4 to 30 psig. Analyte List: (See C2-C12 Hydrocarbon List) Analytical System Column: Detector: HP1, 0.32mm ID, 60m, 1µm film Al2O3 PLOT Column, 50m, 6890 GC/ dual FID Application: Application Brief Analysis of C2-C12 Hydrocarbons using dual column, dual FID detection. EPA Method: When to Use: T016 (Tentative) When cryogenless preconcentration and analysis is required. Summary: Whole air samples are collected in SUMMA passivated canisters or analyzed on-site in real time. Sample size is cc. C2-C6 compounds are separated on a 60m,.32mm Al 2 O 3 plot column. C6-C12's are separated on a 60m DB1,.32mm, 1 micron film thickness. Scan Range: Solvent Delay: 5 Hz, 2 channels ne Temperatures deg C Preconcentration System and Method Parameters Event Description M1 M1 blkhd M2 M2 Blkhd M3 Concentration: Preheat: no Desorption: * Bakeout: Flows and Volumes Medium Preflush(sec) Flow Rate(sccm) Vol.(cc) Internal Standard Analytical Standard Sample Final sweep/purge flush M1-M2 Transfer Event Duration Zone Temp. Rotary Valves 100 GC Transfer Line 100 Manifold xfer Line 80 Autosampler rotary valve 80 Sample Ambient Event Min. M2 Desorb to er 2.5 Injection 2 Bakeout 5 er Bakeout (Event 3) 3 Wait time after Injection 25 (after last analyte elutes) Options Pressure Compensation - 14 CTD Second Temp - NA Max. Temp Below Setpoint: Mod deg. C Mod deg. C Extra M2 to M3 Transfer Time after start of Injection Min. * - t Controlled Directly. Inject Gas Heated Application tes 9-14

15 Inlet/Autosampler Module 1 Module 2 Module Canisters 6789 Bags Tubes/ Hi Flow Inj. Loop GC Injector Purge & Nafion Dryer Empty Bead / System Hardware Configuration GC MS Loop Inj. C2 - C12 genless Ambient temperature preconcentration of C2-C12 hydrocarbons followed by capillary chromatography requires at least 2 sorbent trapping stages. The purpose of the first stage is to supply enough sorbent to keep the C2 hydrocarbons from breaking through the trap before the end of the trapping procedure and final trap flush. This requires a fairly wide bore trap with a length considerably longer than classical traps. Since desorption of the first trap can occur with a relatively small backflush volume (10-30cc), a much narrower secondary trap can be used to further concentrate the sample before injection onto a capillary column for separation and analysis. Rapid injection off the second trap will insure that narrow peaks are obtained in the chromatogram. As there is a vast difference in boiling points between C2 and C12 hydrocarbons, no one column can currently separate the entire range without the use of cryogenic cooling. Therefore two columns become necessary. One column resolves the light ends and the other separates the heavier hydrocarbons. These can be arranged in parallel or in series using either pressure diversion or rotary valve flow switching. Series operation is generally preferred because the heavier fraction is kept off the column optimized for the light ends. This will reduce or eliminate the occurrence of ghost peaks (heavy compounds finally eluting from the column from a previous injection). Each column is usually configured with its own FID, generating two quantitation files that can be merged together in a spreadsheet or database. Hydrocarbon Concentration Events using s (2-Stage Preconcentration - er) Procedure: MP&T 1. Waiting for temperatures to reach setpoints 2. Optional wait for GC Ready 3. Cool Modules 1 trapping temperature 4. Preflush with Internal Standard 5. Internal Standard 6. Preflush with Analytical Standard 7. Analytical Standard 8. Preflush with Sample 9. Sample 10. Preflush with Helium sweep/purge gas 11. Helium sweep/purge gas 12. Preheat Module Transfer VOCs from M1 --> M2 14. Wait for GC Ready 15. Cool focusing trap 16. Optional M2 preheat 17. Transfer M2 --> M3 18. Heat M3, Inject, Start GC 19. Preflush with next sample 20. System bakeout 21. Wait time since injection te: All cooling is by fan Application tes 9-15

16 Plumbing The Oven Application tes 9-16

17 Application tes 9-17

18 Analysis of 1/4" and 6mm Adsorbent Tubes using the 7100 Thermal Desorption Option ( ) Parameters Sample Concentration: Sample Collection device: Sample Matrix: Water Management: Sample Pressure: Analyte List: Analytical System Column: Detector: 1 ppb ppb 1/4"x4 or 6mm x 11.5cm" tubes Air or Artificial Matrix Microscale Purge and Atmospheric See TO1, TO2, TO17 list DB1/DB5, 0.32mm ID, 60m, 1µm film GC/MSD, Ion Application: Analysis of non-polar halogenated and aromatic organic compounds in ambient air, stack and landfill gas, andindustrial hygiene. EPA Method: When to Use: Summary: Application Brief TO1, TO2, TO17 For sampling applications requiring tubes. Air samples are collected in the field on single or multibed sorbent tubes. VOC's are analyzed by GC or GC/ MS by preconcentrating and focusing in the Water is eliminated using Microscale Purge and Scan Range: Solvent Delay: amu (1-2 Hz) 0 minutes Instrument: 7100A with Option Event Description M1 M1 blkhd M2 M2 Blkhd M3 Concentration: Preheat: no Desorption: * Bakeout: Flows and Volumes Medium Preflush(sec) Flow Rate(sccm) Vol.(cc) Internal Standard Analytical Standard Sample Final sweep/purge flush M1-M2 Transfer Zone Temp. Rotary Valves 100 GC Transfer Line 100 Manifold xfer Line 80 Autosampler rotary valve 80 Sample Ambient Event Duration Event Min. M2 Desorb to er 3.5 Injection 2 Bakeout 5 er Bakeout (Event 3) 3 Wait time after Injection 25 (after last analyte elutes) Options Pressure Compensation - 14 CTD Second Temp - NA Max. Temp Below Setpoint: Mod deg. C Mod deg. C Extra M2 to M3 Transfer Time after start of Injection - 0 Min. * - t Controlled Directly. Inject Gas Heated Application tes 9-18

19 Inlet/Autosampler Module 1 Module 2 Module3 Canisters Bags Tubes/ Hi 6789 Flow Inj. Loop GC Injector Purge & Loop Inj. Nafion Dryer Empty Bead / Module System Hardware Configuration GC 6 MS 6 Concentration Events When required, tubes can be desorbed singly into the 7100A preconcentrator using the thermal desorption option. Potential losses from dry purging can be avoidedby directly desorbing the sample and water vapor into the 7100 where the moisture can be eliminated using Microscale Purge and (MP&T). Internal standards can be added automatically to each analysis A wide selection of 6mm x 11.5 cm tubes are available from Supelco with different diameters and and adsorbent packings. Tubes with built in glass frits should be used to reducethe potential for adsorbent getting transferred into the preconcentrator. 1. Wait for temperatures to reach setpoints 2. Optional wait for GC Ready 3. Cool Module 1 to trapping temperature 4. Preflush with Internal Standard 5. Internal Standard 6. Preflush with Analytical Standard 7. Analytical Standard 8. (Skip Sample Preflush) 9. Desorb sample with cc helium 10. Preflush with Helium Sweep/Purge gas 11. Flush trap w/ Helium Sweep/Purge gas 12. Preheat Module Transfer VOCs from M1 --> M2 14. Wait for GC Ready 15. Cool focusing trap 16. Optional M2 preheat 17. Transfer M2 --> M3 18. Heat M3, Inject, Start GC 19. Preflush with next sample 20. System bakeout 21. Wait time after injection Application tes 9-19

20 Formaldehyde and VOCs in Indoor Air using Silonite Coated Canisters and CTD Preconcentration Parameters Sample Concentration: 1ppb ppb Sample Collection device: Silonite Canisters Sample Matrix: Indoor Air /Ambient Air Water Management: Cold Dehydration Sample Pressure: -4 to 30 psig Analyte List: Formaldehyde + TO15 List Analytical System Column: Detector: DB1/DB5, 0.32mm ID, 60m, 1µm film GC/MSD, Ion Application Brief Application: Analysis of Formaldehyde and Indoor Air volatile chemicals. See Appl. te 101 for detailed information EPA Method: IP1 When to Use: Simplifies the analysis of a wider range of indoor air pollutants using a single test. Especially useful in investigative studies where a universal technique is desired. Summary: Air samples are collected in Silonite MiniCans or 6L canisters. VOC's and formaldehyde are analyzed by GC/ MS after cryogenic preconcentration and focusing. Scan Range: Solvent Delay: amu, 0-6min (3-4 Hz) amu (3 Hz) 0 minute Instrument: 7100/(7032 or 7500) Parameters: Event Description M1 M1 blkhd M2 M2 Blkhd M3 Concentration: Preheat: no Desorption: Bakeout: Flows and Volumes Medium Preflush(sec) Flow Rate(sccm) Vol.(cc) Internal Standard * Analytical Standard Sample Final sweep/purge flush M1 --->M2 Transfer NA Zone Event Duration Temp. Rotary Valves 100 GC Transfer Line 100 Autosampler xfer Line 80 Autosamp Rot. Valve 80 Sample Event Min. M2 Desorb to er 3.5 Injection 1.5 Bakeout (M1 and M2) 7 er Bakeout (Event 3) 3 Wait Time after injection 25 * - Int. Std is 25 PPB Acetone-d6, dry in 15L Silonite Canister Application tes 9-20

21 Inlet/Autosampler Module 1 Module 2 Module Silonite Canisters Tubes/ Hi Flow Inj. Loop GC Injector Purge & Nafion Dryer Empty 678 Bead / Module System Hardware Configuration GC MS Loop Inj. Formaldehyde and VOCs in Indoor Air using Cold Dehydration Moisture Management The successful analysis of formaldehyde in air requires careful selection of sampling equipment and conditions. Silonite canisters have been shown to allow formaldehyde to be collected and stored for 1-2 weeks, although this has not yet been demonstrated in SUMMA canisters. During sampling and analysis, it is very important to keep formaldehyde away from condensed water, as formaldehyde forms a complex with water and will be almost complete removed from the gas phase. Sampling with pumps must definitely be avoided because water condensation and subsequent formaldehyde loss will most certainly occur. Cold Dehydration moisture management allows the CO2 and most of the water in the sample to be eliminated prior to GC injection. Linear response has been demonstrated from 20 to 400 cc. Above 400cc, the formaldehyde reponse drops off, and the amount of tailing increases as well indicating that more water has been introduced onto the column. To minimize water in the analysis, it is recommended to use a nonhumdified internal standard (acetone-d6) in a Silonite coated canister. The analysis of carbonyls in ambient air can be accomplished with a standard 400cc sample size, with detection limits down to 0.2 PPB for formaldehyde. Detection limits of around 0.05 PPB can be achieved using SIM monitoring. Procedure: MP&T 1. Waiting for temperatures to reach setpoints 2. Optional wait for GC Ready 3. Cool Modules 1 trapping temperature 4. Preflush with Internal Standard 5. Internal Standard 6. Preflush with Analytical Standard 7. Analytical Standard 8. Preflush with Sample 9. Sample 10. Preflush with Helium sweep/purge gas 11. Helium sweep/purge gas 12. (skip) 13. (skip) 14. Wait for GC Ready 15. Cool focusing trap 16. Optional M2 preheat (skip) 17. Transfer M2 --> M3 18. Heat M3, Inject, Start GC 19. Preflush with next autosampler position 20. System bakeout 21. Post injection delay Application tes 9-21

22 Trace Analysis in High CO 2 Matrices Using Cold Dehydration Parameters Sample Concentration: Sample Collection device: Sample Matrix: Water Management: Sample Pressure: Analyte List: Analytical System Column: Detector: Scan Range: 0.1ppb ppb SUMMA cans or Tedlar bags Soil, Landfill, stack gas & auto exhaust Cold Dehydration -4 to 30 psig See TO14 list DB1/DB5, 0.32MM ID, 60m, 1µm film 5973 GC/MSD, Ion, GC/FID/PID/ECD amu (1-2 Hz) Application: Analysis of trace polar and nonpolar contaminants, including halogenated, aromatic, and oxygenated VOC's in high CO2 matricies (landfill, CO2 purity) EPA Method: When to Use: Application Brief Modified TO14 For analysis of both polar and nonpolar VOC's whenever high CO2 levels make normal cryogenic preconcentrations ineffective. Summary: Whole air samples are collected in canisters, MiniCans or Tedlar bags. VOC's are analyzed by GC/MS after subambient sorbent preconcentration of cc of sample. Solvent Delay: 0 minutes Temperatures deg C Preconcentration System and Method Parameters Event Description M1 M1 blkhd M2 M2 Blkhd M3 Concentration: Preheat: no Desorption: * Bakeout: Flows and Volumes Medium Preflush(sec) Flow Rate(sccm) Vol.(cc) Internal Standard Analytical Standard Sample Final sweep/purge flush M1-M2 Transfer Event Duration Zone Temp. Rotary Valves 100 GC Transfer Line 100 Manifold xfer Line 80 Autosampler rotary valve 80 Sample Ambient Event Min. M2 Desorb to er 3.5 Injection 2 Bakeout 7 er Bakeout (Event 3) 3 Wait time after Injection 28 (after last analyte elutes) Options Pressure Compensation - 14 CTD Second Temp - t Selected Max. Temp Below Setpoint: Mod deg. C Mod deg. C Extra M2 to M3 Transfer Time after start of Injection - 0 Min. * - t Controlled Directly. Inject Gas Heated Application tes 9-22

23 Inlet/Autosampler Module 1 Module 2 Module Canisters Bags Tubes/ Hi Flow Inj. Loop GC Injector Purge & Nafion Dryer Empty 678 Bead / Module System Hardware Configuration GC MS Loop Inj. High CO 2 Landfill and stack gases are often times very rich in CO 2. Trace analysis in such a matrix presents a problem for conventional cryogenic trapping because CO 2 is also trapped at these temperatures. With CO 2 concentrations sometimes greater than 50%, a very small sample volume (10-15 cc) can completely block up the cryogenic trap. A modification to the trapping procedure can be made which allows CO 2 to pass through the trap while concentrating the organics. Since CO 2 is a gas at temperatures above -78 O C and pressures below 30 psi, the trap can simply be operated at temperatures around -60 O C. To keep volatile organic compounds from breaking through the trap, Tenax is used. As with most chemical sorbents, Tenax becomes a much stronger sorbent as temperature decreases. At -60 O C, breakthrough volumes should be times greater than at room temperature for many VOCs. When analyzing dry CO2, a modification of this approach can be performed which can provide better recovery of other very light compounds (H2S, formaldehyde, COS, etc). In this case, Tenax traps are used in both M1 and M2, and the sample is concentrated using MP&T. The trapping temperature of M1 is set to -70 C, while a setpoint of -60 C is used in M2. Both M1 and M2 are desorbed at 180 C to deliver the sample to the next stage. Procedure: /Cold Dehydration 1. Wait for temperatures to reach setpoints 2. Optional wait for GC Ready 3. Cool Module 1 to trapping temperature 4. Preflush with Internal Standard 5. Internal Standard 6. Preflush with Analytical Standard 7. Analytical Standard 8. Preflush with Sample 9. Sample 10. Preflush with Helium Sweep/Purge gas 11. Helium Sweep/Purge gas 12. Preheat Module1 13. Transfer remaining VOCs from M1-->M2 14. Wait for GC Ready 15. Cool focusing trap 16. Optional M2 preheat 17. Transfer M2 --> M3 18. Heat M3, Inject, Start GC 19. Preflush with next sample 20. System bakeout 21. Wait time after injection Application tes 9-23

24 Trace Analysis of Reduced Sulfur Compounds Using Extended Cold Dehydration Parameters Sample Concentration: Sample Collection device: Sample Matrix: Water Management: Sample Pressure: Analyte List: Analytical System Column: Module 1 : Detector: Scan Range: Solvent Delay: 0.1ppb ppb Silonite Canisters, MiniCans All gas phase matrices with total NMHC <10ppm Extnd. Cold Dehydration -4 to 30 psig See attached list DB1/DB5, 0.32MM ID, 60m, 1µm film module, Blank GC/MSD, Ion amu (3 Hz) 0 minute Temperatures deg C Application: Analysis of H2S, COS, C1-C4 Mercaptans, Alkyl mono-, di-, and tri- sulfides, at ppb and sub ppb levels. EPA Method: When to Use: For analysis of reduced sulfur compounds when low levels and the conformation afforded by GC/MS is necessary. Full scan detection limits can reach <0.1ppb. Summary: Application Brief ne written yet Whole air samples are collected in Silonite coated canister or MiniCans. Reduced sulfur compounds are analyzed by GC/ MS after subambient sorbent preconcentration of cc of sample. Preconcentration System and Method Parameters Event Description M1 M1 blkhd M2 M2 Blkhd M3 Concentration: Preheat: no Desorption: * Bakeout: Flows and Volumes Medium Preflush(sec) Flow Rate(sccm) Vol.(cc) Internal Standard Analytical Standard Sample Final sweep/purge flush M1-M2 Transfer Event Duration Zone Temp. Rotary Valves 100 GC Transfer Line 100 Manifold xfer Line 80 Autosampler rotary valve 80 Sample Ambient Event Min. M2 Desorb to er 3 Injection 2 Bakeout 5 er Bakeout (Event 3) 3 Wait time after Injection 28 (=RT of Last Analyte) Options Pressure Compensation - 14 CTD Second Temp - 50 deg. C Max. Temp Below Setpoint: Mod deg. C Mod deg. C Extra M2 to M3 Transfer Time after start of Injection Min. * - t Controlled Directly. Inject Gas Heated Application tes 9-24

25 Inlet/Autosampler Module 1 Module 2 Module Canisters Bags Tubes/ Hi Flow Inj. Loop GC Injector Purge & Nafion Dryer Empty 678 Bead / Module System Hardware Configuration GC MS Loop Inj. Reduced Sulfur Cmpd Analysis Reduced sulfur compounds have been difficult to analyze in the past at low levels because of the inability to preconcentrate them without loss of reactive species of this class of compounds, including H2S and the light mercaptans. Sampling problems have been overcome using fused silica lined stainless steel canisters. These canisters have a layer of fused silica on their internal surface which prevents H2S and mercaptans from being exposed to stainless steel. In a stainless steel container, H2S will disappear within just a few hours. However, H2S is stable in fused silica lined canisters for 5-7 days or more. When purchasing these canisters from Entech, the fused silica lined valve option should be requested (6L Cans:PN , MiniCans: PN 29-MC400S). This completes the passivation of the entire wetted surface. Extended Cold Dehydration removes water vapor by transforming the water from a vapor directly to a solid in the empty module 1 trap. It is important to use Entech's "empty" trap to eliminate the interaction of H2S with otherwise active surfaces. Module 2 is cooled down to -90 C to prevent H2S from breaking through. At this temperature, much of the CO2 will be retained, so a final flush of the M2 trap at -50 deg. C is required (see option section on opp. page). Procedure: Extended Cold Dehydration 1. Wait for temperatures to reach setpoints 2. Optional wait for GC Ready 3. Cool Module 1 to trapping temperature 4. Preflush with Internal Standard 5. Internal Standard 6. Preflush with Analytical Standard 7. Analytical Standard 8. Preflush with Sample 9. Sample 10. Preflush with Helium Sweep/Purge gas 11. Flush M2 with Helium at elevated temp. 12. Preheat Module 1(skip) 13. Transfer remaining VOCs from M1-->M2 (skip) 14. Wait for GC Ready 15. Cool focusing trap 16. Optional M2 preheat (normally off) 17. Transfer M2 --> M3 18. Heat M3, Inject, Start GC 19. Preflush with next sample 20. System bakeout 21. Wait time after injection To analyze for H2S using a mass spectrometer, start scanning at 31 amu. H2S elutes within 5-10 seconds of the CO2 peak, after which the starting mass can be increased to 34 amu to avoid the oxygen response at m/z 32. Application tes 9-25

26 Analysis of SVOCs using Heated Silonite Canister Analysis Parameters Sample Concentration: 0.1 ppb - 50 ppb Sample Collection device: Silonite MiniCans Sample Matrix: Air, Headspace, Indoor Air Water Management: Dual Stage Tenax /Dry Purge Sample Pressure: -6 to 20 psig Analyte List: Based on Monitoring Needs Analytical System Column: Detector: DB1/DB5, 0.32mm ID, 60m, 0.5 to 1µm film GC/MSD, Ion Application Brief Application: Analysis of approximately C6 to C18 Compounds in Silonite coated MiniCans Method: When to Use: Extends the range of Compounds recoverable from canisters up to C20. Includes 2-3 ring aromatics, pesticides, flavor and fragrance compounds, remote headspace. Summary: samples are collected in Silonite MiniCans. Heavier VOC's and SVOC's are analyzed by GC/MS after dual Tenax trap preconcentration and water elimination. Scan Range: Solvent Delay: amu (3 Hz) 0 minute Instrument: 7100A/7500 Parameters: Event Description M1 M1 blkhd M2 M2 Blkhd M3 Concentration: Preheat: Desorption: Bakeout: Flows and Volumes Medium Preflush(sec) Flow Rate(sccm) Vol.(cc) Internal Standard * Analytical Standard NA NA NA Sample Final sweep/purge flush Zone Event Duration Temp. Rotary Valves 150 GC Transfer Line 150 Autosampler xfer Line 130 Autosamp Inlet 130 Sample 120 Event Min. M2 Desorb to er 4 Injection 2 Bakeout (M1 and M2) 10 er Bakeout (Event 3) 2 Wait Time after injection 25 * - Analytical Std must be injected from heated sample position Application tes 9-26

27 Inlet/Autosampler Module 1 Module 2 Module Tubes/ Hi Flow Inj. Loop GC Injector Purge & Nafion Dryer Empty Bead 6789 / Module GB/ System Hardware Configuration GC MS Loop Inj. SVOC Analysis in Canisters Canisters have previously be limited to the analysis of compounds with a relatively high vapor pressure at 25 deg. C (room temperature). These compounds are classified as "Volatile Organic Compounds" if they have a vapor pressure greater than 0.2 mm Hg at 25 deg. C. With the availability of Silonite coating and heated canister inlet systems, the molecular weight range has been extended considerably to include the C13 to C20 range (up to C25 with the 8000 inlet). The standard water management procedures, MP&T and ECTD, cannot be used for water removal due to the low vapor pressure of SVOCs at reduced desorption and dehydration temperatures. Instead, a dry purge technique is used in which the sample is delivered onto a glass bead / Tenax trap in M1 and then dry purged to eliminate the water. The heavier compounds (C16+) will trap largely on the glass beads, with the lighter compounds migrating through and trapping on the Tenax bed. Although trapping and dry purging could be done in M2 directly, that would require recovery of the SVOCs under the slow flow of the carrier gas. This is difficult as many of these compounds have been pushed down into the bed during the large sampling volume or during the dry purge at 30 deg. C. ping in M1 allows a large volume and fast flow rate for best recovery from the M1 trap. Cold trapping on M2 insures that the compounds will be near the front of M2 for easy recovery. SVOC canister stds can be made by injecting MeOH mixes into canisters followed by heated analysis as per actual samples Procedure: MP&T 1. Waiting for temperatures to reach setpoints 2. Optional wait for GC Ready 3. Cool Modules 1 trapping temperature (30 C) 4. Preflush with Internal Standard 5. Internal Standard 6. (skip - std must come from sample position) 7. (skip...) 8. Select sample, preflush = 0 9. Sample 10. Preflush with Helium sweep/purge gas 11. Helium sweep/purge gas 12. Preheat M1 13. Transfer M1 to M2 14. Wait for GC Ready 15. (skip) 16. M2 preheat 17. (skip) 18. Inject from M2, Start GC 19. (skip) 20. System bakeout 21. Post injection delay Application tes 9-27

28 Analysis of Microbial VOCs (MVOCs) for Mold Detection in Indoor Air Parameters Sample Concentration: ng/l Sample Collection device: Silonite MiniCans Sample Matrix: Indoor Air Water Management: Dual Tenax / Dry Purge Sample Pressure: -4 to 15 psig Analyte List: (See Std MVOC List) Analytical System Column: Detector: DB1/DB5, 0.32mm ID, 60m, 1µm film GC/MSD, Ion Application Brief Application: Analysis of Microbial VOCs in Indoor Air as indicators of active mold growth. EPA Method: When to Use: Faster and potentially more accurate than spore counting. Summation of 21 major MVOCs (in ng/l) should be compared to average for area in order to determine relative mold levels Summary: Air samples are collected in Silonite MC400L, MC600L, or MC1400L MiniCans. Samples are heated to 80 deg. C followed by analysis of mls of sample using dry purge water management. Scan Range: Solvent Delay: amu, 0-6min (3-4 Hz) amu (3 Hz) 0 minute Instrument: 7100A/7500 Parameters: Event Description M1 M1 blkhd M2 M2 Blkhd M3 ping: Preheat: no Desorption: Bakeout: Flows and Volumes Medium Preflush(sec) Flow Rate(sccm) Vol.(cc) Internal Standard Analytical Standard * Sample Final sweep/purge flush Zone Event Duration Temp. Rotary Valves 130 GC Transfer Line 120 Autosampler xfer Line 120 Autosamp Rot. Valve NA Sample 80 Event Min. M2 Desorb to er 3.5 Injection 2.0 Bakeout (M1 and M2) 10 er Bakeout (Event 3) 3 Wait Time after injection 20 * - Calibration Standard must be injected into MiniCan from MeOH std mix and heated to 80 deg. C like samples. Application tes 9-28

29 Inlet/Autosampler Module 1 Module 2 Module Silonite Canisters Tubes/ Hi Flow Inj. Loop GC Injector Purge & Nafion Dryer Empty Bead 6789 / Module System Hardware Configuration GC MS Loop Inj. Microbial VOC Analysis Microbial VOCs are produced by actively growing mold in indoor air. Unlike spores, these MVOCs cannot be transmitted very far outside without being eliminated by sun light and atmospheric reactions, so their presence in a building strongly supports the presence of growing mold. Again unlike spores, MVOCs can pass through walls and carpeting to distribute themselves throughout the indoor environment, making them easier to detect when only collecting 1 or 2 canister samples. There are roughly 21 compounds, mostly oxygenates, that are used to determine whether actively growing molds are present. Sampling can be done using a Quick Fill Sampler (QFS) within just a few seconds. The Silonite canisters must be heated manually or in the 7500 autosampler to recover the heavier MVOCs. The analysis is performed using the MP&T procedure with a glass bead / Tenax trap in M1 at 30 deg. C allowing water to be removed by forward dry purging. Back desorption at 50 cc/min to an M2 Tenax trap at -50 deg. C will keep the heavier MVOCs near the front of the second trap making them easier to recovery using normal capillary column flow rates (1.5-2cc/ min). ing should be performed in order to improve the injection rate of the lighter MVOCs for improved chromatography and better detection limits. MVOCs can be analyzed using GCMS methods similar to those used for TO15. Procedure: MP&T 1. Waiting for temperatures to reach setpoints 2. Optional wait for GC Ready 3. Cool Modules 1 trapping temperature (30 C) 4. Preflush with Internal Standard 5. Internal Standard 6. Preflush with Analytical Standard 7. Analytical Standard 8. Preflush with Sample 9. Sample 10. Preflush with Helium sweep/purge gas 11. Helium sweep/purge gas and cool M2 12. Preheat M1 13. Transfer M1 to M2 14. Wait for GC Ready 15. Cool focusing trap 16. Optional M2 preheat (skip) 17. Transfer M2 --> M3 18. Heat M3, Inject, Start GC 19. Preflush with next autosampler position 20. System bakeout 21. Post injection delay Application tes 9-29

30 Large Volume Headspace Analysis of Liquid and Solid Samples Application Brief Application: Analysis C2 to C12 Volatiles in the headspace of liquid and solid samples down to sub-ppb levels Parameters Sample Concentration: Sample Collection device: Sample Matrix: Water Management: Sample Pressure: Analyte List: Analytical System Column: Module 1 : Detector: Scan Range: Solvent Delay: Flows and Volumes ppb ppb LVH Vials Headspace in Liq and Solids MP&T 0-4 psig See attached list DB1/DB5, 0.32MM ID, 60m, 1µm film module, Blank GC/MSD, Ion amu (3 Hz) 0 minute Temperatures deg C Event Description M1 M1 blkhd M2 M2 Blkhd M3 Concentration: Preheat: no Desorption: * Bakeout: Medium Preflush(sec) Flow Rate(sccm) Vol.(cc) Internal Standard Analytical Standard Sample Final sweep/purge flush M1-M2 Transfer EPA Method: When to Use: For characterizing odors, aroma and off-flavor compounds, materials testing, beverages analysis. Summary: ne written yet Solid or liquid samples are placed in Large Volume Headspace (LVH) vials ( mls). The sample is heated or analyzed at room temperature by pulling 10 to 300 mls of headspace into the 7100A Preconcentration System and Method Parameters Event Duration Zone Temp. Rotary Valves 100 GC Transfer Line 100 Manifold xfer Line or Sample Inlet 100 Sample C Event Min. M2 Desorb to er 3.5 Injection 2 Bakeout 10 er Bakeout (Event 3) 3 Wait time after Injection 28 (=RT of Last Analyte) Options Pressure Compensation - 14 Max. Temp Below Setpoint: Mod deg. C Mod deg. C Extra M2 to M3 Transfer Time after start of Injection - 0 Min. * - t Controlled Directly. Inject Gas Heated Application tes 9-30

31 Inlet/Autosampler Module 1 Module 2 Module3 Canisters Bags Tubes/ Hi Flow Inj LVH Vial 678 GC Injector Purge & Nafion Dryer Empty Bead / Module System Hardware Configuration GC MS Loop Inj. Large Volume Headspace Analysis The analysis of headspace compounds down to olfactory detection limits (sub-ppb in many cases) has not been possible due to the limited sensitivity of a GCMS relative to the human nose for many flavor and odor compounds. Most headspace instruments inject the equivalence of 0.2 mls during the analysis (3 15:1 split) which reveals only the highest concentration analytes. What has been needed is a headspace inlet that can preconcentrate hundreds of mls of headspace down to just a few microliters for very rapid GC injection. Large Volume Headspace Vials (LVH Vials) allow 10 to 50 g of sample to be loaded into a 350 or 470 ml glass vial, providing up to 300 mls of available headspace for trace analysis. These vials can either be run one-at-a-time on the 7100A, or automated through the 7500 autosampler in a 28 position tray. Preheating of the sample is possible to increase the headspace concentration of less volatile compounds. The analysis parameters shown at left are for standard MP&T water/co2 management allowing recovery of C2-C12 range volatiles. For alcoholic beverages, the ethanol and lighter compounds can be eliminated by operating the M1 trap at 35 deg. C and forward purging before back-desorbing to M2. This has the disadvantage of loosing the very light VOCs, but allows recovery of the heavier C12-C18 fraction due to the higher desorption temperatures for M1 and M2. H2S and other compounds lighter than ethanol can be analyzed by using ECTD and running the M1 GB/Tenax trap at 0 deg. C to elute only the light compounds to M2 for analysis. Procedure: Microscale P&T 1. Wait for temperatures to reach setpoints 2. Optional wait for GC Ready 3. Cool Module 1 to trapping temperature 4. Preflush with Internal Standard 5. Internal Standard 6. Preflush with Analytical Standard 7. Analytical Standard 8. Preflush with Sample 9. Sample 10. Preflush with Helium Sweep/Purge gas 11. Flush M2 with Helium at elevated temp. 12. Preheat Module 1(skip) 13. Transfer remaining VOCs from M1-->M2 (skip) 14. Wait for GC Ready 15. Cool focusing trap 16. Optional M2 preheat (normally off) 17. Transfer M2 --> M3 18. Heat M3, Inject, Start GC 19. Preflush with next sample 20. System bakeout 21. Wait time after injection Application tes 9-31