NYC-WTC_000219925

NYC 9/11 Public Portal Document

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analysis procedures. Because the test is sensitive, it may be influenced by a variety of factors. These include the supplies used in the sampling operation, the performance of the sampling, the preparation of the grid from the filter and the actual examination of this grid in the microscope. Each of these unit operations must produce a product of defined quality if the analytical result is to be a reliable and meaningful test result. Accordingly, a series of control checks and reference standards are to be performed along with the sample analysis as indicators that the materials used are adequate and the operations are within acceptable limits. In this way, the quality of the data is defined and the results are of known value. These checks and tests also provide timely and specific warning of any problems which might develop within the sampling and analysis operations. A description of these quality control/quality assurance procedures is summarized in the following Table III:

TABLE III - SUMMARY OF LABORATORY DATA QUALITY OBJECTIVES Conformance Unit Operation OC Check Frequency Expectation Sample receiving Review of receiving Each sample 95% complete report Sample custody Review of chain-of Each sample 95% complete -custody record Sample preparation Supplies and On receipt Meet specs, or reagents rej ect Grid opening size 20 openings/20 grids/lot 100% Of 1000 or 1 opening/sample Special clean area After cleaning or Meet specs monitoring service reclean Laboratory blank 1 per prep series Meet specs, or or 10% reanalyze series Plasma etch blank 1 per 20 samples 75% Multiple preps (3 Each sample One with cover of per sample) 15 complete grid sqs. Sample analysis System check Each day Each day Alignment check Each, day Each day Magnification cali- Each month or after 95% bration with low service and high standards ED calibration by Weekly 95% gold standard EDS calibration by Daily 95% copper line Performance check Laboratory blank Prep 1 per series Meet specs or (measure of clean or 10% reanalyze series liness) read 1 per 25 samples Replicate counting 1 per 100 samples 1.5 X Poisson Std. (measure of preci- Dev.

http://lexis/research/retrieve?_m=el35£2ca3d266867e53d261df3205722&_fmtstr=FULL5 ... 02/04/2002 CITY_21MC100_012558674

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