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0RDER QC REPORT: Definitions and Terms Accuracy The ability of a procedure to determine the `true' concentration of an analyte ` Precision The reproducibility of a pro(edure demonstrated by the agreement between analyse~ / pertormed on either duplicates of the same sample or a pair of duplicate spikes Batch A group of twenty sample~ or less, of similar matrix type, prepped together or analyzed together if no sample preparation is required, under the same conditions and with the same reagents The batch must include a method blank, LCS and matrix QC Laboratory A blank that is spiked with a known amount of analyte and subjected to the same Control Standard procedures as the samples The LCS indicates the accuracy of the analytical method (LCS) It also serves to double-(,heck the calibration because it is prepared from a ditfe rent source than the standard used to calibrate the instrument Matrix QC Quality control performed on actual client samples The matrix Spike is a client',, sample spiked with a known amount of analyte For most analyses,the laboratory performs matrix spikes in duplicate (duplicate spikes) Method Blank A trample that contains no analyte For water analysis, organic-free or deiontzed water is used For solids analysis,analyte-free solvent is used The method blank serves to measure contamination associated with laboratory storage, preparation or instrumentation Batch Number Numeric designation for a batch of samples and the associated QC The batch number sequence is unique for each determination LC Result Laboratory result of an LCS analysis LT Result Expected result, or true value, of the LCS analysis iPercent Recovery The percentage of analyte recovered For LCS, the percent recovery calculation is LC/LT x 100 LCI, LC'2 Result Result of analyzing two separately prepared LCSs, used to determine precision RI, R2 Result Result of analyzing replicate aliquots of a sample, with RI indicating the first analysis cit the sample and R2 its corresponding duplicate, used to determine precision S I, S2 Result Result of the analysis of replicate spiked aliquots, with S l indicating one Spike of the sample and S2 the second spike, used to determine precision and accuracy Relative Percent Calculated using one of the following Difference (RPD) LLC 1 —LC21 x 100 IRI —R21 x 100 ISI — S21 x 100 (LCI + LC2)—2 (RI + R2) —2 (SI + S2) -2 S i, S2 Recovery The percentage of analyte recovered The pei.,ent recovery calculation is Sl RecoveryS( I — R I) x 100 S2 Recovery (S2— R_1) x 100 (True— R 1) (True— RI) True Value The theoretical,or expected, result of a spike sample analysis NC Flag Indicates that the spike recovery was not calculated due to high sample concentration relative to the amount of spike added Q Flag Indicates that the quality control measurement is outside the specified control limits • Blank Result Laboratory result of analysis of the method blank Reporting BCA—assigned limit based on, but not the same as, method.detection limits Detection Limit (MDLs) determined using EPA guidelines Sample RDL% may differ from the (RDL) blank RDL if the samples were diluted B C Analytical 10193