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CRA MEMORANDUM Page <br /> 10.0 Matrix Spike/Matrix Spike Duplicate (MS/MSD) Analyses <br /> To evaluate the effects of sample matrices on the extraction or digestion process, measurement <br /> procedures, and accuracy of a particular analysis, samples are spiked with a known concentration of the <br /> analyte of concern and analyzed as MS/MSD samples. The relative percent difference (RPD) between the <br /> MS and MSD is used to assess analytical precision. If the original sample concentration is significantly <br /> greater than the spike concentration,the recovery is not assessed. <br /> The MS/MSD samples were spiked with all compounds of interest. All percent recoveries and RPD values <br /> were within the laboratory control limits, demonstrating acceptable analytical accuracy and precision. <br /> 11.0 Field QA/QC Samples <br /> The field QA/QC consisted of one trip blank sample, one field blank sample, one equipment blank sample <br /> and one field duplicate set. <br /> Trip Blank Sample Analysis <br /> To evaluate contamination from sample collection, transportation, storage, and analytical activities, the trip <br /> blank was submitted to the laboratory for VOC analysis. All results were non-detect for the compounds of <br /> interest. <br /> Field/Equipment Blank Sample Analysis <br /> To assess field decontamination procedures, ambient conditions at the site, and cleanliness of sample <br /> containers, the field and equipment blanks were submitted for analysis, as identified in Table 1. All results <br /> were non-detect for the analytes of interest. <br /> Field Duplicate Sample Analysis <br /> To assess the analytical and sampling protocol precision,the field duplicate sample was collected and <br /> submitted "blind"to the laboratory, as specified in Table 1. The RPDs associated with these duplicate <br /> samples must be less than 50 percent for water samples. If the reported concentration in either the <br /> investigative sample or its duplicate is less than five times the practical quantitation limit(PQL),the <br /> evaluation criterion is one times the PQL value for water samples. <br /> No targeted analytes were reported as detected in the field duplicate sample set. <br /> 12.0 Target Compound Identification <br /> To minimize erroneous compound identification during organic analyses, qualitative criteria including <br /> compound retention time and mass spectra, if applicable,were evaluated according to the identification <br /> criteria established by the methods. <br /> EQUN WKMMEM OPMO MEMKWEP <br />