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3 of 6 <br /> GORE-SORBED Screening Survey <br /> 4' Final Report <br /> ANALYTICAL PROCEDURES <br /> ' W L Gore&Associates' Screening Module Laboratory operates under the guidelines of its Quality <br /> Assurance Manual, Operating Procedures and Methods The quality assurance program is consistent with <br /> Good Laboratory Practices (GLP)and ISO Guide 25, "General Requirements for the Competence of <br /> ' Calibration and Testing Laboratories",third edition, 1990 <br /> Instrumentation consists of state of the art gas chromatographs equipped with mass selective detectors, <br /> coupled with automated thermal desorption units Sample preparation simply involves cutting the tip off <br /> the bottom of the sample module and transferring one or more exposed sorbent containers(sorbers, each <br /> containing 40mg of a suitable granular adsorbent)to a thermal desorption tube for analysis Sorbers <br /> ' remain clean and protected from dirt, soil, and ground water by the insertion/retrieval cord, and require <br /> no further sample preparation <br /> ' Analytical Method Quality Assurance- <br /> The analytical method employed is a modified EPA method 8260/8270 Before each run sequence,two <br /> instrument blanks, a sorber containing 5µg BFB (Bromofluorobenzene), and a method blank are <br /> analyzed The BFB mass spectra must meet the criteria set forth in the method before samples can be <br /> analyzed A method blank and a sorber containing BFB is also analyzed after every 30 samples and/or <br /> trip blanks Standards containing the selected target compounds at three calibration levels of 5, 20, and <br /> 50µg are analyzed at the beginning of each run The criterion for each target compound is less than 35% <br /> ' RSD (relative standard deviation) If this criterion is not met for any target compound, the analyst has <br /> the option of generating second- or third-order standard curves, as appropriate A second-source <br /> reference standard, at a level of 10µg per target compound, is analyzed after every ten samples and/or <br /> ' trip blanks, and at the end of the run sequence Positive identification of target compounds is determined <br /> by 1)the presence of the target ion and at least two secondary ions, 2)retention time versus reference <br /> standard, and, 3)the analyst's judgment <br /> ' NOTE All data have been archived Any replicate sorbers not used in the initial analysis will be discarded <br /> fifteen (15)days from the date of analysis <br /> ' Laboratory analysis: thermal desorption, gas chromatography, mass selective detection <br /> Instrument ID. # 7 Chemist. JW <br /> ' Compounds/mixtures requested: Gore Fuel Hydrocarbons (A2), GRPH and DRPH <br /> Deviations from Standard Method: None <br /> Comments- Soil vapor analytes and abbreviations are tabulated in the Data Table Key(page 6) <br /> ' Modules 9402118, -122, and—140 were found lying on the ground during module retrieval <br /> Geological Technics requested no analysis of these modules <br /> GORE-SORBEt ss a registered trademark and svice ark ofW L Gare&Asso <br /> Associates <br />