Standard reference materials, NBS

Cali JP, Mandel J, Moore L, and Young DS (1972) A Referee Method for the Determination of Calcium in Serum Standard Reference Materials. NBS Spec Publ 260-36. National Bureau of Standards, Washington, DC. 

Standard Reference Material, NBS, NIST, Trade Mark... 

E. S. Gladney, C. E. Burns, D. R. Perrin, I. Roelandts, T. E. Gill, 1982 Compilation of Elemental Concentration Data for NBS Biological, Geological, and Environmental Standard Reference Materials, NBS Special Publication, 1984, 260-288. 

Table 14.3. Nominal concentrations of the Standard Reference Material NBS 1648 Particulate constituents.

Information on standard samples with specified chemical composition and physical properties, including standard samples for x-ray spectrometric analysis, is given in Catalog of NBS Standard Reference Materials. NBS Special Publication 260, 1975-76 ed. (Superintendent of Documents, U.S. Government Printing Office, Washington, D.C. 20402.)... 

Taylor, J.K. (1985) Handbook for SRM Users — Standard Reference Materials, NBS Special Publication 260-100 U.S. Department of Commerce National Bureau of Standards, Gaithersberg MD. USA. 

Certified values and values measured for Standard Reference Material NBS 1572, citrus... 

V, Cr, Ni, Co. Cu, Mo, Pt. Hg and Bi in urine have been determined by ICP-MS following an on-line column reiention/elution of the bis(carboxymethyl)- dithiocarbamate complex, achieving detection limits in the range 8-80 ng 1" [18J. Cr, Ni, and Pi were determined in a urine standard reference material NBS-SRM 2670, and the results agreed well with the recommended values. 

ISCC-NBS Centroid Color Charts, NBS Standard Reference Material No. 2106, National Institute of Standards and Technology, Washiagton, D.C.,... 

Only one isotope, Pu-244, is presently available as a NBS Standard Reference Material and can be obtained from the DOE New Brunswick Laboratory. A second NBS/SRM as a 1 1 mixture of... 

Procedures for determining the spectral responslvlty or correction factors In equation 2 are based on radiance or Irradlance standards, calibrated source-monochromator combinations, and an accepted standard. The easiest measurement procedure for determining corrected emission spectra Is to use a well-characterized standard and obtain an Instrumental response function, as described by equation 3 (17). In this case, quinine sulfate dlhydrate has been extensively studied and Issued as a National Bureau of Standards (NBS) Standard Reference Material (SRM). 

Cali JP, Mears TW, Michaelis RE, Reed WP, Seward RW, Stanley CL, Yolken HT, and Ku HH (1975) The role of standard reference materials in measurement systems. NBS Monograph 148, Washington DC. 

Cali JP, and Reed WP (1976) The role of the National Bureau of Standards standard reference materials in accurate trace analysis. In Lafleur PD, ed. Accuracy in Trace Analysis Sampling, Sample Handling, and Analysis, NBS Special Publication 422, Vol i pp 41-63. National Bureau of Standards, Washington, DC. 

De Goeij JJM, VorKERS KJ, Tjioe PS, and Kroon JJ (1978) NBS SRM 1569 Brewer s yeast Is it an adequate standard reference material for testing chromium determination in biological materials. Radiochem Radioanal Letters 35 139-146. 

Gladney ES (1980) Elemental concentrations in NBS biological materials and environmental standard reference materials. Anal Chim Acta 118 385-396. 

Gladney ES, O Malley BT, Roeiandts I, and Gills TE (1987,1993 update) Standard Reference Materials Compilation of Elemental Concentration Data for NBS Chemical, Biological Geological and Environmental SRMs. NBS Spec Pub 260-111, NIST, Gaithersburg, MD. 

ID-TIMS has frequently been used for certification of Standard Reference Materials by NIST (ex NBS) and IRMM (ex BCR), as in case of the Polymer Elemental Reference Material (PERM) project for the production of PE standards with certified concentrations of eight elements, namely Cd, Cr, Hg, Pb, As, S, Cl and Br [1], Also certification of the VDA-001 to -004 PE/Cd CRMs has taken advantage of both ID-TIMS [224,425] and... 

For exact temperature evaluation the thermocouple must be calibrated with temperature standards. Today commercial temperature standards are available Nat. Bureau of Standards (NBS) Washington offers standard reference materials (No 759, 758, 760) as DTA-temperature standards 6a-e for 3 temperature ranges ... 

Table 3. DTA-Temperature Standards NBS-ICTA standard reference material...

Based upon studies with the NBS standard reference materials, the linear calibration method appears to give equivalent accuracy compared to a peak position method irrespective of sample disperslty provided that the sample elute over the elution volume range covered by the polydlsperse standard and low dispersion SEC column are utilized. 

Certified Reference Materials. Certified Reference Materials are materials whose properties have been guaranteed or certified by recognized bodies. The certified analyses of these materials can be used as an estimate of the "true" value for assessment of accuracy. The United States National Bureau of Standards (NBS) provides an inventory of various materials whose compositions (and properties) have been measured using definitive and reference methods. These materials, Standard Reference Materials (SRM s), when used in conjunction with reference methods, i.e., one of demonstrated accuracy, make it possible to transfer accuracy between measurement protocols. 

Call, J. Paul and Reed, William P. "The Role of the National Bureau of Standards Standard Reference Materials in Accurate Trace Analysis." pp41-63 in. Accuracy in Trace Analysis Sampling. Sample Handling. Analysis., Proceedings of the 7th Materials Research Symposium NBS Special Publ. 422, yol. 1 2 Ed. by Philip D, LaFleur., U.S. Department of Commerce, National Bureau of Standards August, 1976. 

Kanare, H. M. 1986. Preparation and characterisation of three new NBS fly ash standard reference materials. Materials Research Society Symposium Proceedings, 65, 159-160. 

One problem is the availability of reliable reference materials for isotope ratio measurements. Certified isotope standard reference materials are available from NIST (National Institute of Standard Reference Materials, http //www.nist.gov/srd/, formerly NBS - National Bureau of Standards) and IRMM (Institute for Reference Materials and Measurements, http //www.irmm.jrc.de). There are isotope standard reference materials for light elements (H, Li, , C, N, O), Mg (magnesium metal isotopic standard NIST SRM 980), and for moderately heavy elements such as (potassium chloride isotopic standard NIST SRM 985), Cr (chromium metal isotopic standard NIST... 

The application of SIMS, SNMS, SSMS and GDMS in quantitative trace analysis for conducting bulk material is restricted to matrices where standard reference materials (SRMs) are available. For quantification purposes, the well characterized multi-element SRMs (e.g., from NIST) are useful. In Table 9.5 the results of the analysis by SNMS and the RSCs (relative sensitivity coefficients) for different elements in a low alloy steel standard (NBS 467) are compared with those of SSMS. Both solid-state mass spectrometric techniques with high vacuum ion sources allow the determination of light non-metals such as C, N, and P in steel, and the RSCs for the elements measured vary from 0.5 to 3 (except C). RSCs are applied as a correction factor in the analytical method used to obtain... 

Major component, best determined by other means,—i.e., the analyst has little confidence in this value. b Sample 3 is standard reference material 124c from the United States National Bureau of Standards. The last line (NBS values) shows the values on the analysis certificate, based on a number of wet determinations for each element using 1-gram samples. The alloy also contains P =. 024%, Si =. 002%,... 

In November 1971, NBS issued Standard Reference Material (SRM) 1630, Mercury in Coal, with a provisionally certified mercury content of 0.13 ppm. Later the provisional value of 2.1 ppm selenium in SRM 1630 was issued. 

For a trace element concentration to be certified by NBS, it must be determined by at least two independent methods, the results of which must agree within a small experimental error range of 1% to 10%, depending on the nature of the sample and the concentration level of the element. Such accuracy in determining some trace elements for certification of coal SRM is achieved most easily by NAA with radiochemical separation. Scientists at NBS have extensively tested a neutron activation method that involves a combustion separation procedure on coal as well as on several other matrices to be certified as standard reference materials. The procedures they have thus developed to determine mercury (12), selenium (13), and arsenic, zinc, and cadmium (14) are outlined in a following section on methods for determining specific elements in coal. 

Precision and Accuracy. Table I shows the results of tests on the linear polyethylene NBS Standard Reference Material No. 1475. This reference material has a pellet-to-pellet coefficient of variation of 3% in the limiting viscosity number according to the NBS Certificate. At least 50 pellets are recommended for a representative sample on which limiting viscosity number is obtained. Nine analyses were performed over a period of about one month on the pellets, using approximately three pellets per determination. The analysis of these data is shown in Table I along with a comparison with the NBS data and their estimate of precision. 

Standard Reference Material 1470 is a 23 micrometer thick polyester film whose gas transmission characteristics with respect to helium, carbon dioxide, oxygen, and nitrogen have been carefully measured. A completely computerized manometric permeation measuring facility developed at NBS was used for the measurements. The steps taken to characterize the gas transmission rate of this material over the range of pressures from 67.5 kPa to 135 kPa and over the range of temperatures from 18 °C to 31 °C are described. The results obtained in these measurements are compared with those in the literature. The role of Standard Reference Material 1470 in improving the repeatability and reproducibility of gas transmission measurements employing other instrumentation is discussed. 

SRM (NBS) Standard reference material (National Bureau of Standards) a Direct oxidation method, n = 3 b HN03-H202,m = 5... 

Table 7.5. Acid-soluble lead and cadmium levels (jxg/g) in NBS standard reference materials (from [96])...

Schramel [103] discusses the conditions for multi-element analysis of over 50 trace elements, giving detection limits. Wolnik [104] described a sample introduction system that extends the analytical capability of the inductively coupled argon plasma/polychromator to include the simultaneous determination of six elemental hydrides along with a variety of other elements in plant materials. Detection limits for arsenic, bismuth, selenium and tellurium range from 0.5 to 3 ng/ml and are better by at least an order of magnitude than those obtained with conventional pneumatic nebulisers, whereas detection limits for the other elements investigated remain the same. Results from the analysis of freeze-dried crop samples and NBS standard reference materials demonstrated the applicability of the technique. Results obtained by the analysis of a variety of plant materials are presented in Table 7.10. 

Detection limits range from 0.02ng/ml for arsenic to 0.80ng/ml for selenium, and precision values at lOng/ml are less than 6% relative standard deviation. Results of analyses of NBS standard reference materials (wheat flour, rice flour, spinach and orchard leaves) demonstrate the application of the method to the matrices. The layout of the apparatus is illustrated in Fig. 7.6. 

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