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Published byLily Gill Modified over 11 years ago
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Manufacture, Homogeneity & Stability of PT samples SPEX CertiPrep/Protocol Analytical 203 Norcross Ave, Metuchen, NJ 08840 vsivakumar@SPEXCSP.Com
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2 Studies Offered Waste Water (WP) Drinking Water (WS) DMRQA Chem DMRQA WET Microbiology (WS) Microbiology (WP)
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3 Overview Manufacture Analysis Assigned value Homogeneity Stability Reporting
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4 Follow EPA (NERL Ci0045) Criteria And NELAC Documents Provide Labs Equal Challenge Use Random Numbers to Select Concentrations within Range Follow Historical Design Guidelines Basis for Separation of Analytes Stability Spectral and chemical influences Regression Equations from Historical Data Rules for Number of Analytes Required to be Present Sample Design
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5 Raw materials from certified source Analysis for impurities in the raw material Assay for analyte content Weigh out compound Dissolve Add matrix reagent Dilute to volume Flame seal in pre-cleaned glass ampules Manufacture
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6 Verification Analysis Manufacture as per design Verification Analysis NIST RULE: Quality Check: Prepared Value is within + 1/3 of acceptance limit to a maximum of + 10% of the Prepared Value
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7 Verification Analysis NELAC RULE: Mean of the verification analysis shall be within 1.5 standard deviation as calculated for Laboratory acceptance.
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8 Method Repeatability NIST RULE: Method Repeatability expressed as standard deviation shall be within 1/6 acceptance limits as calculated for the laboratories ( to a maximum of 5% of the prepared value).
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9 Method Repeatability NELAC RULE Repeatability limit is 0.5 sd
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10 Homogeneity Done prior to sample shipment To establish all samples distributed to the laboratories have the same assigned value for every parameter to be evaluated. Done on final packaged samples Samples are selected randomly Number of samples depend on the total number of ampules Samples are picked from the beginning, middle and end of the packaging run
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11 Homogeneity Samples may be considered homogenous if Sx < 0.25C When there is no apparent visual trend.
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13 UNCERTAINTY Associated With Preparation Purity Of Raw Material Weighing Make Up To Volume
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14 Stability Absolute difference between the mean of the homogeneity verification value (X)and stability verification value should be |X – Y| < 0.2C or Stability value is within 1/3 acceptance limits given for the laboratories
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15 Stability
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16 Reports Final assigned values Study Statistics Review of the Study for pass/fail rate Study Summary Study Discussion Study data Individual Laboratory Reports
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