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Sample Holding Time and Preservation <br />The sample holding time criteria and sample preservation requirements for the analyses are summarized in <br />the methods. The sample chain of custody document and analytical report were used to determine sample <br />holding times. All samples were prepared and analyzed within the required holding times. <br />All sample containers were properly preserved, delivered on ice and stored by the laboratory at the required <br />temperature (0-6°C). <br />Laboratory Method Blank Analyses <br />Method blanks are prepared from a purified matrix and analyzed with investigative samples to determine the <br />existence and magnitude of sample contamination introduced during the analytical procedures. <br />For this study, laboratory method blanks were analyzed at a minimum frequency of 1 per 20 investigative <br />samples and/or 1 per analytical batch. <br />All method blank results were non-detect, indicating that laboratory contamination was not a factor for this <br />investigation. <br />Surrogate Spike Recoveries <br />In accordance with the method employed, all samples, blanks, and QC samples analyzed for organics are <br />spiked with surrogate compounds prior to sample extraction. Surrogate recoveries provide a means to <br />evaluate the effects of laboratory performance on individual sample matrices. <br />All samples submitted for diesel range organics (DRO)/motor oil range organics (ORO) analysis were spiked <br />with the appropriate number of surrogate compounds prior to sample extraction. <br />Surrogate recoveries were assessed against the control limits. All surrogate recoveries met the associated <br />criteria. <br />Laboratory Control Sample Analyses <br />Laboratory control samples (LCS) are prepared and analyzed as samples to assess the analytical <br />efficiencies of the methods employed, independent of sample matrix effects. <br />For this study, LCS were analyzed at a minimum frequency of 1 per 20 investigative samples and/or 1 per <br />analytical batch. <br />Organic Analyses <br />The LCS contained all analytes of interest. All LCS recoveries were within associated control limits, <br />demonstrating acceptable analytical accuracy. <br />GHD 11183954M emo-707.docx 2