Optimal VOC Method Parameters for the StratUm PTC Purge & Trap Concentrator

Optimal VOC Method Parameters for the StratUm PTC Purge & Trap Concentrator Application Note Introduction Environmental laboratories have utilized the Purge & Trap sample concentration technique for over 30 years. This classical technique offers many benefits in regards to increasing sample throughput without sacrificing final detection sensitivity. The StratUm PTC offers a fresh new approach to Purge & Trap that now offers unprecedented precision, accuracy, and system cleanliness. The increased precision and accuracy are achieved by the utilization of an ultra-fast trap heater. By desorbing the compounds of interest off the analytical trap quickly and efficiently, the StratUm PTC will assist in achieving superior chromatography, which in turn results in better reportable data. The system cleanliness is enhanced by the StratUm PTC s new sample flow path. The new flow path has made great strides to ensure heating consistency throughout the entire sample pathway, thus minimizing any potential coldspots, which may trap or slow down certain compounds. Another innovation, which helped enhance system cleanliness, is the superior inert tube coating utilized by the StratUm PTC. Background contamination is dramatically reduced to give you better analytical performance. This application note will discuss optimal method parameters for achieving a calibration curve of 0.5 to 200ppb for 102 Volatile Organic Compounds (VOCs). The target compounds are found in the US Environmental Protection Agency (USEPA) 8260B list. Experimental Five standard mixes were used to make up the reported compound list. They were purchased from Restek (www.restek.com) See Table 1 for details. The calibration was built with concentrations of 0.5, 5.0, 25, 100, and 200ppb. An Agilent 6890GC and 5973MS were used for separation and detection. The purge and trap concentrator utilized was the Teledyne Tekmar StratUm PTC. The autosampler used was the Teledyne Tekmar SolaTek 72 Multi Matrix Sampler. The SolaTek 72 added the internal standards automatically during the sample transfer. The sample purging was performed in the StratUm PTC. The adsorbant trap utilized was the Vocarb Strat-Trap. Optimal method parameters can be found in Tables 2 and 3.

Table 1. Reported Compound Mix Standard Mix Cat # or Specific Compounds 8260B MegaMix Calibration Mix Cat # 30475 502.2 Calibration Mix #1 (gases) Cat # 30042 VOA Calibration Mix #1 (ketones) Cat # 30006 8260B Acetate Mix (revised) Cat # 30489 California Oxygenates Mix Cat # 30465 Internal Standards Surrogates Pentaflourobenzene, 1,4 Diflourobenzene, Chlorobenzene d5 Dibromoflouromethane, Toluene d8, BFB Table 2. StratUm PTC Parameters (utilizing a Vocarb Strat Trap) Variable Value Variable Value Valve Oven Temp 140 Deg C Dry Purge Flow 100 ml/min Transfer Line Temp 140 Deg C Dry Purge Temp. 20 Deg C Sample Mount Temp 90 Deg C Desorb Preheat 250 Deg C Purge Ready Temp 35 Deg C Desorb Temp. 250 Deg C Condenser Ready Temp 40 Deg C Desorb Time 2.00 min Condenser Purge Temp 20 Deg C Desorb Flow 400 ml/min Purge Time 11 min Trap Bake Temp 290 Deg C Purge Flow 40 ml/min Trap Bake Time 5.0 min GC Start Start of Desorb Trap Bake Flow 400 ml/min Dry Purge Time 1.00 min Condenser Bake Temp 225 Deg C Table 3. GC/MS Parameters Variable GC Column / Gas RTX VMS Value 20m x 0.18mm, 1.00 micrometer film; He at 1.0 ml/min GC Injector GC Oven Mass Spec Split ratio: 80:1, Temp 150 deg C Int. temp 35 deg C, hold 2.00 min; Ramp rate of 14.00 deg/min to 85 deg C, hold for 0.00 min.; Ramp rate of 40.00 deg/min to 210, hold for 3.00 min.; (Total run time of 11.70 min) Interface at 250 C, MS quad 150 C; MS source at 230 C, low mass 35 amu

Calibration Curve Data Compound Ave. RF %RSD Compound Ave. RF %RSD Pentafluorobenzene (IS) ISTD 2 Cleve 0.225 5.16 Dichlorodifluoromethane 0.630 9.61 1,2,3 Trichloropropane 0.589 7.00 Chloromethane 0.886 9.37 cis 1,3 Dichloropropene 0.592 6.60 Vinyl Chloride 0.708 8.52 Toluene d8 (surr) 1.754 9.31 Bromomethane 0.344 7.52 Toluene 1.702 4.08 Chloroethane (Ethyl Chloride) 0.238 6.96 2 Nitropropane 0.052 9.20 Trichlorofluoromethane 0.058 6.84 Tetrachloroethene 0.702 8.96 Diethyl Ether 0.429 8.68 4 Methyl 2 Pentanone 0.051 9.47 Carbon Disulfide 1.088 6.20 trans 1,3 Dichloropropene 0.538 7.12 1,1,2 Trichlorofluoroethane (Freon ) 0.393 9.53 1,1,2 Trichloroethane 0.400 8.33 Iodomethane 0.501 9.14 Ethyl Methacrylate 0.473 9.29 Allyl Chloride 0.843 9.73 Dibromochloromethane 0.270 7.80 Methylene Chloride 0.806 9.80 1,3 Dichloropropane 0.634 8.30 Acetone 0.204 9.37 1,2 Dibromoethane 0.407 7.85 trans 1,2 Dichloroethene 0.718 8.59 n Butyl Acetate 0.652 6.86 Diisopropyl Ether 1.763 8.95 2 Hexanone 0.324 4.51 Ethyl Acetate 0.349 5.88 Chlorobenzene d5 (IS) ISTD Chloroprene 0.813 5.72 Chlorobenzene 1.162 7.29 cis 1,2 Dichloroethene 0.503 8.31 Ethylbenzene 1.893 8.69 1,1 Dichloroethane 0.937 7.34 1,1,1,2 Tetrachloroethane 0.295 5.00 Methyl Acetate 0.465 9.74 M&P Xylene 0.656 9.63 Methyl tert Butyl Ether(MTBE) 1.230 9.71 Ortho Xylene 1.414 9.20 tert Butyl Alcohol (TBA) 0.282 4.38 Styrene 1.125 9.13 Acetonitrile 0.083 5.27 Bromoform 0.259 7.20 Acrylonitrile 0.217 6.70 Isopropylbenzene 1.796 9.54 Propionitrile 0.223 8.01 Tetrahydrofuran (THF) 0.783 8.26 Ethyl tert Butyl Ether (ETBA) 1.473 6.07 n Amyl Acetate 0.782 8.26 1,1 Dichloroethene 0.843 9.59 BFB (surr) 0.745 7.37 2,2 Dichloropropane 0.755 6.97 n Propylbenzene 2.146 9.83 Bromochloromethane 0.668 9.79 trans 1,4 Dichloro 2 Butene 0.163 9.85 Chloroform 1.087 6.57 Nitrobenzene 0.903 9.76 Carbon Tetrachloride 0.537 8.50 Bromobenzene 0.513 4.65 Methyl Acrylate 0.594 5.47 1,1,2,2 Tetrachloroethane 0.512 6.10 1,1,1 Trichloroethane 0.773 7.84 1,3,5 Trimethylbenzene 1.487 8.72 Dibromofluoromethane (surr) 0.773 7.84 2 Chlorotoluene 1.517 4.94 1,1 Dichloropropene 0.764 6.77 cis 1,4 Dichloro 2 Butene 0.205 7.64 2 Butanone (MEK) 0.333 4.72 4 Chlorotoluene 1.459 7.09 Benzene 2.319 9.69 Tertbutylbenzene 1.364 9.40 Methacrylonitrile 0.424 8.82 Pentachloroethane 0.131 5.43 tert Amyl Methyl Ether (TAME) 1.401 6.50 1,2,4 Trimethylbenzene 1.125 8.66 1,2 Dichloroethane 0.934 7.90 sec Butylbenzene 1.897 9.56 Isobutyl Alcohol 0.025 7.07 p Isopropyltoluene 1.503 9.33 Isopropyl Acetate 1.178 6.93 1,3 Dichlorobenzene 0.919 9.89 Trichloroethene 0.600 5.80 1,4 Dichlorobenzene 0.976 6.61 1,4 Difluorobenzene (IS) ISTD n Butylbenzene 1.540 7.98 Dibromomethane 0.258 2.75 1,2 Dichlorobenzen 0.942 9.89 1,2 Dichloropropane 0.050 8.21 1,2 Dibromo 3 Chloropropane 0.067 8.31 Bromodichloromethane 0.461 8.21 Hexachlorobutadiene 0.333 6.31 Methyl Methacrylate 0.390 6.82 1,2,4 Trichlorobenzene 0.675 9.54 2 Chloroethanol 0.039 7.38 Naphthalene 1.430 7.98 n Propyl Acetate 0.612 4.77 1,2,3 Trichlorobenzene 0.650 4.39

Sample Results from 30 Consecutive Runs: In order to demonstrate the repeatability of the StratUm PTC, the 50ppb calibration mixture was analyzed 30 consecutive times to demonstrate repeatability and accuracy. The entire analysis time for 30 runs was approximately 15 hours. This demonstrates calibration curve robustness, system reliability, and performance. Although all of the compounds in the list were analyzed, this paper reports four compounds representing different molecular weight ranges. Sample Name Ave (ppb) Std Dev (ppb) RSD (%) Vinyl Chloride 47.91 1.80 3.76 Iodomethane 48.64 2.84 5.84 2 Cleve 51.33 1.59 1.44 Naphthalene 48.30 1.70 3.52 Vinyl Chloride 50ppb Repeatability 60 58 56 54 52 50 48 46 44 42 40 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 a n a l y si s r e p l i c a t e Iodomethane 50ppb Repeatability 60 58 56 54 52 50 48 46 44 42 40 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 analysis r eplicat e

2 Cleve 50ppb Repeatability 60 58 56 54 52 50 48 46 44 42 40 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 a na l y si s r e pl i c a t e Naphthalene 50ppb Repeatability 60 58 56 54 52 50 48 46 44 42 40 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 a na l y si s r e p li c a t e MDL Calculation The minimum detection limit was determined by running seven replicates of the 0.5ppb calibration curve standard. The appropriate factor was applied and the MDLs calculated are presented in the following table. Compound run 1 run 2 run 3 run 4 run 5 run 6 run 7 Ave std dev MDL Dichlorodifluoromethane 0.55 0.56 0.57 0.51 0.49 0.59 0.55 0.55 0.03 0.11 Chloromethane 0.59 0.57 0.56 0.65 0.56 0.56 0.59 0.58 0.03 0.10 Vinyl Chloride 0.58 0.48 0.58 0.54 0.57 0.46 0.58 0.54 0.05 0.16 Bromomethane 0.57 0.58 0.5 0.54 0.51 0.55 0.57 0.55 0.03 0.10 Chloroethane 0.51 0.49 0.59 0.56 0.53 0.49 0.51 0.53 0.04 0.12 Trichlorofluoromethane 0.57 0.55 0.47 0.57 0.48 0.55 0.57 0.54 0.04 0.14 Carbon Disulfide 0.57 0.49 0.56 0.58 0.53 0.54 0.57 0.55 0.03 0.10 Iodomethane 0.5 0.5 0.57 0.55 0.48 0.55 0.5 0.52 0.03 0.11 Methylene Chloride 0.54 0.59 0.54 0.56 0.51 0.48 0.54 0.54 0.03 0.11 Trans 1,2 dichloroethene 0.5 0.55 0.55 0.57 0.54 0.59 0.5 0.54 0.03 0.11 1,1 Dichloroethane 0.58 0.48 0.5 0.55 0.54 0.59 0.58 0.55 0.04 0.13 Propiontrile 0.5 0.57 0.52 0.5 0.47 0.5 0.5 0.51 0.03 0.10 1,1 Dichloroethene 0.5 0.54 0.55 0.49 0.54 0.46 0.5 0.51 0.03 0.10 2,2 Dichloropropane 0.49 0.48 0.48 0.57 0.45 0.53 0.49 0.50 0.04 0.12 Bromochloromethane 0.5 0.5 0.55 0.57 0.54 0.53 0.5 0.53 0.03 0.09 Chloroform 0.47 0.57 0.53 0.58 0.57 0.56 0.47 0.54 0.05 0.15 Carbon Tetrachloride 0.51 0.53 0.53 0.52 0.48 0.58 0.51 0.52 0.03 0.10 1,1,1 Trichloroethane 0.56 0.5 0.48 0.58 0.53 0.57 0.56 0.54 0.04 0.12

Compound run 1 run 2 run 3 run 4 run 5 run 6 run 7 Ave std dev MDL Dibromofluoromethane (surr) 0.56 0.51 0.51 0.54 0.54 0.58 0.56 0.54 0.03 0.08 1,1 dichloropropene 0.57 0.54 0.48 0.55 0.55 0.54 0.57 0.54 0.03 0.10 Benzene 0.55 0.56 0.53 0.57 0.53 0.47 0.55 0.54 0.03 0.10 1,2 Dichloroethane 0.55 0.54 0.57 0.55 0.54 0.53 0.49 0.54 0.02 0.08 Trichloroethane 0.5 0.58 0.55 0.49 0.53 0.52 0.5 0.52 0.03 0.10 Dibromomethane 0.54 0.55 0.54 0.56 0.51 0.51 0.54 0.54 0.02 0.06 1,2 Dichloropropane 0.51 0.54 0.56 0.46 0.51 0.53 0.51 0.52 0.03 0.10 Bromodichloromethane 0.53 0.52 0.49 0.52 0.52 0.55 0.53 0.52 0.02 0.06 2 Cleve 0.58 0.51 0.59 0.49 0.57 0.57 0.58 0.56 0.04 0.12 Cis 1,3 Dichloropropene 0.47 0.56 0.5 0.57 0.53 0.59 0.47 0.53 0.05 0.15 Toluene d8 (surr) 0.56 0.53 0.53 0.51 0.48 0.52 0.56 0.53 0.03 0.09 Toluene 0.51 0.57 0.54 0.52 0.56 0.54 0.51 0.54 0.02 0.07 Tetrachloroethene 0.54 0.46 0.5 0.49 0.51 0.54 0.54 0.51 0.03 0.10 Trans 1,3 Dichloropropene 0.55 0.53 0.53 0.53 0.57 0.56 0.55 0.55 0.02 0.05 1,1,2 Trichloroethane 0.51 0.54 0.53 0.57 0.59 0.57 0.51 0.55 0.03 0.10 Dibromochloromethane 0.58 0.5 0.48 0.51 0.53 0.55 0.58 0.53 0.04 0.12 1,3 Dichloropropane 0.57 0.57 0.5 0.52 0.56 0.56 0.57 0.55 0.03 0.09 1,2 Dibromoethane 0.51 0.51 0.5 0.57 0.52 0.52 0.51 0.52 0.02 0.07 Chlorobenzene 0.57 0.51 0.49 0.53 0.55 0.51 0.57 0.53 0.03 0.10 Ethylbenzene 0.58 0.56 0.49 0.48 0.49 0.49 0.58 0.52 0.05 0.15 1,1,1,2 Tetrachloroethane 0.57 0.52 0.58 0.47 0.48 0.51 0.57 0.53 0.05 0.14 M&P Xylene 1.07 1.04 0.98 1.11 1.06 0.98 1.07 1.04 0.05 0.15 O Xylene 0.49 0.5 0.54 0.52 0.52 0.51 0.49 0.51 0.02 0.06 Styrene 0.45 0.45 0.42 0.41 0.45 0.47 0.45 0.44 0.02 0.06 Bromoform 0.29 0.26 0.46 0.32 0.25 0.41 0.29 0.33 0.08 0.25 Isopropylbenzene 0.5 0.48 0.52 0.49 0.54 0.45 0.5 0.50 0.03 0.09 BFB (surr) 0.48 0.48 0.48 0.5 0.45 0.53 0.48 0.49 0.02 0.08 N propylbenzene 0.55 0.58 0.52 0.52 0.58 0.5 0.55 0.54 0.03 0.10 Bromobenze 0.58 0.51 0.5 0.53 0.56 0.58 0.58 0.55 0.03 0.11 1,1,2,2 Tetrachloroethane 0.49 0.5 0.47 0.54 0.5 0.47 0.49 0.49 0.02 0.07 1,3,5 Trimethylbenzene 0.53 0.54 0.51 0.51 0.5 0.56 0.53 0.53 0.02 0.07 2 Chlorotoluene 0.54 0.48 0.46 0.57 0.56 0.46 0.54 0.52 0.05 0.15 Trans 1,4 Dichloro 2 Butene 0.52 0.47 0.56 0.51 0.59 0.55 0.52 0.53 0.04 0.12 4 Chlorotoluene 0.55 0.55 0.51 0.52 0.54 0.48 0.55 0.53 0.03 0.08 Tertbutylbenzene 0.5 0.5 0.49 0.5 0.48 0.53 0.58 0.51 0.03 0.11 1,2,4 Trimethylbenzene 0.55 0.53 0.49 0.47 0.47 0.53 0.55 0.51 0.04 0.11 Sec Butylbenzene 0.54 0.57 0.58 0.51 0.53 0.59 0.54 0.55 0.03 0.09 P Isopropyltoluene 0.51 0.51 0.47 0.59 0.53 0.51 0.51 0.52 0.04 0.11 1,3 Dichlorobenzene 0.53 0.51 0.47 0.47 0.51 0.52 0.53 0.51 0.03 0.08 1,4 Dichlorobenzene 0.54 0.48 0.51 0.48 0.48 0.57 0.54 0.51 0.04 0.11 N Butylbenzene 0.55 0.61 0.54 0.54 0.52 0.51 0.55 0.55 0.03 0.10 1,2 Dichlorobenzene 0.52 0.58 0.56 0.53 0.51 0.57 0.52 0.54 0.03 0.09 1,2 Dibromo 3 Chloropropane 0.43 0.54 0.58 0.52 0.58 0.54 0.43 0.52 0.06 0.20 Hexachlorobutadiene 0.55 0.51 0.55 0.59 0.57 0.54 0.55 0.55 0.02 0.08 1,2,4 Trichlorobenzene 0.53 0.51 0.58 0.51 0.48 0.58 0.53 0.53 0.04 0.12 Naphthalene 0.52 0.49 0.55 0.52 0.5 0.49 0.52 0.51 0.02 0.07 1,2,3 Trichlorobenzene 0.57 0.5 0.57 0.54 0.5 0.48 0.57 0.53 0.04 0.12

System Cleanliness A purge and trap system needs to ensure system cleanliness so that there are no false positive hits immediately after a high concentration sample has been run. A false positive can be the result of a memory effect within the systems flow path or trapping material. The memory effect can most commonly be attributed to one of two issues, activation sites or cold spots. The method parameters called out in this application note will help to ensure that the system will run at optimal performance. The following data represents the running of a 200ppb standard mix and the subsequent 5 blanks. Clearly seen, the carryover effect is minimized by the StratUm s sample path integrity. By showing all compounds going to <0.01% relative detection, this shows the overall cleanliness of the system in regards to component contamination. Compound 200 ppb Std. %Carryover %Carryover %Carryover %Carryover %Carryover Dichlorodifluoromethane 35713512 0.16 0.00 0.00 0.00 0.00 Chloromethane 59130727 0.25 0.00 0.00 0.00 0.00 Vinyl Chloride 49378693 0.33 0.00 0.00 0.00 0.00 Bromomethane 23399072 0.33 0.00 0.00 0.00 0.00 Chloroethane 9181651 0.48 0.00 0.00 0.00 0.00 Trichlorofluoromethane 15848605 0.45 0.00 0.00 0.00 0.00 Carbon Disulfide 88578389 0.42 0.17 0.03 0.00 0.00 Iodomethane 33091073 0.15 0.00 0.00 0.00 0.00 Methylene Chloride 61831388 0.23 0.13 0.00 0.00 0.00 Trans 1,2 dichloroethene 59362919 0.22 0.00 0.00 0.00 0.00 1,1 Dichloroethane 73996934 0.05 0.00 0.00 0.00 0.00 Propiontrile 20150088 0.29 0.00 0.00 0.00 0.00 1,1 Dichloroethene 49959212 0.31 0.00 0.00 0.00 0.00 2,2 Dichloropropane 46724051 0.07 0.00 0.00 0.00 0.00 Bromochloromethane 30185469 0.25 0.00 0.00 0.00 0.00 Chloroform 95848058 0.07 0.00 0.00 0.00 0.00 Carbon Tetrachloride 71283491 0.09 0.00 0.00 0.00 0.00 1,1,1 Trichloroethane 55443869 0.20 0.00 0.00 0.00 0.00 Dibromofluoromethane (surr) 55435234 0.20 0.00 0.00 0.00 0.00 1,1 dichloropropene 75495736 0.31 0.00 0.00 0.00 0.00 Benzene 167259265 0.13 0.04 0.01 0.00 0.00 1,2 Dichloroethane 84286360 0.11 0.00 0.00 0.00 0.00 Trichloroethane 56243444 0.36 0.00 0.00 0.00 0.00 Dibromomethane 36567764 0.21 0.00 0.00 0.00 0.00 1,2 Dichloropropane 66092207 0.02 0.00 0.00 0.00 0.00 Bromodichloromethane 73264532 0.04 0.00 0.00 0.00 0.00 2 Cleve 33897735 0.12 0.00 0.00 0.00 0.00 Cis 1,3 Dichloropropene 87990894 0.15 0.00 0.00 0.00 0.00 Toluene d8 (surr) 141778815 0.35 0.00 0.00 0.00 0.00 Toluene 150017000 0.28 0.11 0.01 0.00 0.00 Tetrachloroethene 73948775 0.73 0.30 0.01 0.00 0.00 Trans 1,3 Dichloropropene 80394641 0.24 0.00 0.00 0.00 0.00 1,1,2 Trichloroethane 52755975 0.00 0.00 0.00 0.00 0.00 Dibromochloromethane 58476689 0.05 0.00 0.00 0.00 0.00 1,3 Dichloropropane 79844085 0.08 0.00 0.00 0.00 0.00 1,2 Dibromoethane 56302883 0.12 0.00 0.00 0.00 0.00 Chlorobenzene 103081107 0.33 0.00 0.00 0.00 0.00 Ethylbenzene 122741400 0.39 0.16 0.00 0.00 0.00 1,1,1,2 Tetrachloroethane 51393508 0.04 0.00 0.00 0.00 0.00 M&P Xylene 131905704 0.67 0.26 0.01 0.01 0.00 O Xylene 112382011 0.31 0.12 0.01 0.00 0.00 Styrene 100363506 0.33 0.14 0.01 0.00 0.00 Bromoform 41346338 0.08 0.00 0.00 0.00 0.00 Isopropylbenzene 116850847 0.37 0.00 0.00 0.00 0.00 BFB (surr) 69771932 0.51 0.00 0.00 0.00 0.00 N propylbenzene 118212205 0.40 0.00 0.00 0.00 0.00 Bromobenze 60185751 0.26 0.00 0.00 0.00 0.00 1,1,2,2 Tetrachloroethane 65398603 0.08 0.00 0.00 0.00 0.00 1,3,5 Trimethylbenzene 103884659 0.45 0.00 0.00 0.00 0.00 2 Chlorotoluene 121702580 0.39 0.00 0.00 0.00 0.00 Trans 1,4 Dichloro 2 Butene 29158237 0.00 0.00 0.00 0.00 0.00 4 Chlorotoluene 100241726 0.42 0.00 0.00 0.00 0.00 Tertbutylbenzene 120643944 0.28 0.00 0.00 0.00 0.00 1,2,4 Trimethylbenzene 104716088 0.47 0.00 0.00 0.00 0.00 Sec Butylbenzene 116638814 0.62 0.00 0.00 0.00 0.00 P Isopropyltoluene 105203818 0.56 0.00 0.00 0.00 0.00 1,3 Dichlorobenzene 86727378 0.54 0.00 0.00 0.00 0.00 1,4 Dichlorobenzene 86815727 0.60 0.00 0.00 0.00 0.00 N Butylbenzene 103733879 0.79 0.00 0.00 0.00 0.00 1,2 Dichlorobenzene 85386719 0.31 0.00 0.00 0.00 0.00

Compound 200 ppb Std. %Carryover %Carryover %Carryover %Carryover %Carryover 1,2 Dibromo 3 Chloropropane 35129010 0.00 0.00 0.00 0.00 0.00 Hexachlorobutadiene 47823456 0.60 0.20 0.01 0.00 0.00 1,2,4 Trichlorobenzene 77942326 0.68 0.25 0.00 0.00 0.00 Naphthalene 111697955 0.98 0.28 0.01 0.00 0.00 1,2,3 Trichlorobenzene 80175858 0.56 0.20 0.00 0.00 0.00 Conclusion The StratUm PTC has demonstrated clear advancements in regard to system performance, repeatability, and cleanliness. These successes are attributed to four key elements. First, excellent purge efficiency by employing a digital mass flow controller to ensure accurate gas handling. Second, ultra-low carryover as a result of the Siltek inert pathway. Third, superior water management being achieved by Tekmar s innovative U condensate trap significantly minimizing the amount of water entering the GC and detector. And forth, the exclusive trapping technique using a rapid nichrome trap heater offers unprecedented gas resolution. All four of these attributes contribute to superior analytical performance of the StratUm PTC.