(SOPs): GC/MS ANALYSES AND DATA PROCESSING METHODS

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MS selected-ion monitoring: Approximate Time range (min.) Dwell Window Mass Time Analyte or Internal Standard 1 24-31 207 1000 Tetrachloro-meta-xylene (GC Internal Standard 2 31-37 284 1000 Hexachlorobenzene 3 37-55 256 1000 PCB 18 and 28 4 55-65 292 1000 PCB 44 and 52 5 65-68 326 1000 PCB 103 (Internal Standard) 6 68-71 115 1000 Oxychlordane 7 71-75 292 1000 PCB 66 8 75-78 373 1000 gamma-chlordane 9 78-87 326 333 PCB 101 409 333 nonachlor III and trans-nonachlor 373 333 alpha-chlordane 10 87-92 246 1000 p,p'-DDE 11 92-97 329 1000 octachlorotoxaphene 12 97-99.6 326 1000 PCB 118 13 99.6-103 409 500 cis-nonachlor 235 500 p,p'-DDD 14 103-107 360 500 PCB 153 326 500 PCB 105 15 107-110 235 500 p,p'-DDT 360 500 PCB 138 16 110-116 394 333 PCB 187 327 333 nonachlorotoxaphene 360 333 PCB 128 17 116-122 394 500 PCB 180 430 500 PCB 170 18 122-126 430 1000 PCB 195 19 126-129 464 1000 PCB 206 20 129-132 498 1000 PCB 209 1. Adjust the Time ranges as necessary (e.g., after GC maintenance) based on the retention times of the analytes. 2. Analyze sets of samples along with five or more calibration standards (referred to as multi-level standards) 2.1. Each multilevel calibration standard contains the analytes at a different concentration so that the concentrations of the calibration standards span the range of analyte concentrations expected to be found in the tissue samples. 2.2. Monitor the GC/MS reproducibility using the mid-level calibration standard. Analyze a mid-level calibration standard at the beginning, middle and end of the series of samples and standards. Data Processing 3. Calculate the concentrations of the analytes relative to the Internal Standard in the samples using the quadratic regression of signal versus concentration in the multilevel standards. [Note that this calibration/calculation process will have its own SOP once the analysis has been validated and the August 17, 2000 2
calculation databases have been developed.] 4. Calculate the lower quantitation limits for analytes in samples using the GC/MS minimum area equivalent to the area of the analytes in the lowest level calibration standard analyzed with the set. 5. Calculate the % recovery of the Internal Standard PCB 103 using the GC Internal Standard Tetrachloro-meta-xylene. 6. Calculate the estimated concentration of total PCBs by multiplying 2 times the sum of the concentrations of the 17 PCB congeners. - DRAFT - August 17, 2000 3
Page 1: STANDARD OPERATING PROCEDURES (SOPs

(SOPs): GC/MS ANALYSES AND DATA PROCESSING METHODS

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