NIST SRMs Organic constituents

SRM 1649A ( ) Urban Dust Organic Constituents NIST... [Pg.143]

SRM 1650A ( ) Diesel Particulate Organic Constituents NIST (being replaced)... [Pg.143]

Three types of SRMs are produced by NIST. Neat reagent SRMs and solution SRMs are intended primarily for instrument calibration whereas complex matrix SRMs are better suited for use as control materials. The amoimt of substance present for relevant constituents(s) is usually reported as a mass fraction with stated uncertainty. Values are usually assigned based on measurements from two or more independent methods. This approach is used to help assure the accuracy of the measurements by identifying potential method biases. A list of complex matrix and solution SRMs available from NIST is provided in Table 13.4. Levels of one or more persistent organic pollutant compoimds are reported for each of these environmental SRMs. A listing of CRMs available from other national metrology institutes has also been compiled [206]. [Pg.373]

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