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Each of the calibration standards is introduced into the <br /> GCMS system using the technique to be used for introduction <br /> of actual samples (ie. 2- to S-ul liquid injections, purge <br /> & trap, etc-) . R series of Calibration Factors C r,z) is <br /> calculated for each analyte, at each standard <br /> concentration. for the mass peak of interest that is <br /> specific for that analyte . <br /> a The Calibration true is a plot of amount introduced <br /> us. the relative response (RR) . <br /> response of analyte <br /> o The RR - --------------------- <br /> response of IS <br /> mass introduced <br /> a The CF - ----------------------- (for multiresponse <br /> total relative response <br /> compounds use the total area of all peaks used for <br /> quantitation) . <br /> a If the percent relatiue standard deviation CXRSD) <br /> between the Cf's is less than 2SX over the working <br /> range, linearity through the origin can be assumed and <br /> an average CF' can be used for quantitation. <br /> D If this criteria is not met, the standard analyses <br /> must be repeated if quantitatLon is to be performed . <br /> The working average Calibration rector must be verified an <br /> each working day by the introduction of one or more <br /> calibration standards . The frequency of verification is <br /> method dependent, and varies from once per day to an <br /> average of once every five samples. <br /> a If the response of any analyte varies from the <br /> predicted response by more than +!- 2OX. a new <br /> calibration curve must be prepared for that analytc . <br /> CRI-R2) <br /> o The Percent Difference ----- x 100, where R1 <br /> R1 <br /> the CF' from the first analysis, and R2 - the CF from <br /> the second analysis . <br /> 17 <br />