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