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' section 10 <br /> O,NSTTE Environmental Labcracones, Inc Revision o <br /> ' Quality Assurance Plan Februan 15, 1996 <br /> Page 2 of 6 <br /> stock standards and are analyzed at a rnuumum of once with each caltoration <br /> ' before any data is quantitated or reported <br /> 10 1 3 Initial and Continuing Calibration Blanks (ICBs and CCBs) and IUutial and <br /> Continuing Calibration Verification (ICV and CCV) <br /> These standards are used to verify the continuing accuracy of the instrument <br /> after it has been calibrated These may or may not be second source standards, <br /> but are of known value and are used to demonstrate that the baseline response <br /> and the calibration have not changed from the initial calibration <br /> ' Unless a blank and an LCS are the first analyses in an analytical batch, an ICB <br /> and 1CV must be analyzed prior to any samples CCBs and CCVs must be <br /> repeated every tenth sample or every 12 hours, depending upon the method <br /> requirement An analytical batch must have a closing CCB and CCV to <br /> demonstrate that contamination has not been introduced and the calibration is <br /> ' unchanged <br /> The equation for calculating the recovery of an ICV or CCV is given in <br /> Section 7 2 2 1 <br /> 10 1 4 Duplicate Samples <br /> ' Laboratory precision is measured by duplicate analysis of samples X11 <br /> analysis, digestion, or extraction batches are required to include a sample split <br /> ' into two aliquots and are analyzed or spiked in duplicate <br /> In this process, two sample aliquots are taken through the entire sample <br /> ' preparation and analysis process Except for the EPA 600 series methods, a <br /> duplicate sample is analyzed for each batch of samples or at a rate of one <br /> duplicate in twenty samples (5%), whichever is more frequent, unless <br /> ' otherwise required by the method The EPA 600 series methods require one <br /> duplicate for every ten samples (10%e) <br /> If duplicate sample analysis is not performed, a sample is spiked in duplicate to <br /> provide information on the precision of analysis <br /> Duplicate sample aliquots are split at the very first stage of the analytical <br /> process and equal aliquots of the sample are used Water samples are mixed <br /> by shaking the sample container and measuring out equal aliquots Unlike field <br /> ' duplicates, precision is usually greater because the samples generally come <br /> from the same sample container <br /> Ward 6 0 Ioeiseci0 doc <br />