ARCHIVED REPORTS_GROUNDWATER MONITORING REPORT - THIRD QUARTER 2013

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Page 2 CRA MEMORANDUM SAMPLE HOLDING TIME AND PRESERVATION The sample holding time criteria for the analyses are summarized in Table 2. Sample chain of custody documents and analytical reports were used to determine sample holding times. All samples were prepared and analyzed within the required holding times. All samples were properly preserved and delivered on ice and stored by the laboratory at the required temperature(0-6°C). GAS CHROMATOGRAPHY/MASS SPECTROMETER(GC/MS)-TUNING AND MASS CALIBRATION (INSTRUMENT PERFORMANCE CHECK) -VOLATILE ORGANIC COMPOUNDS(VOCS) GC MS Prior to analysis,GC/MS instrumentation is tuned to ensure optimization over the mass range of interest. To evaluate instrument tuning,the volatile method requires the analysis of the specific tuning compound bromofluorobenzene(BFB). The resulting spectra must meet the criteria cited in the methods before analysis is initiated. Analysis of the tuning compound must then be repeated every 12 hours throughout sample analysis to ensure the continued optimization of the instrument. Tuning compounds were analyzed at the required frequency throughout the volatile analysis periods. All tuning criteria were met;indicating that proper optimization of the instrumentation was achieved. GC/MS INITIAL CALIBRATION-VOCS To quantify compounds of interest in samples,calibration of the GC/MS over a specific concentration range must be performed. Initially,a five-point calibration curve containing all compounds of interest is analyzed to characterize instrument response for each analyte over a specific concentration range. Linearity of the calibration curve and instrument sensitivity are evaluated against the following criteria: i) All relative response factors(RRFs)must be greater than or equal to 0.05 ii) The percent relative standard deviation(RSD)values must not exceed 30.0 percent or a minimum coefficient of determination of 0.99 if quadratic equation calibration curves are used The initial calibration data for VOCs was reviewed. All compounds met the above criteria for sensitivity and linearity. GC/MS CONTINUING CALIBRATION-VOCS To ensure that instrument calibration is acceptable throughout the sample analysis period,continuing calibration standards must be analyzed and compared to the initial calibration curve every 12 hours. The following criteria were employed to evaluate continuing calibration data: i) All RRF values must be greater than or equal to 0.05 ii) Percent difference(%D)values must not exceed 25 percent