NIST standard reference material SRM

SOURCE OF NIST STANDARD REFERENCE MATERIAL SRM 164 9, AIR PARTICLES ... 

Throughout this chapter, we cite examples of the use of the NIST Standard Reference Material SRM 1649, which is referred to as Air Particles or Urban Air Particulate Matter, (a) to validate analytical procedures for determination of PAHs and PACs in samples of complex mixtures of particulate matter in ambient air and (b) for laboratory intercomparisons of methodologies for bacterial bioassays and bioassay-directed fractionations of organic extracts of such mixtures (e.g., see Claxton et al., 1992a Lewtas et al., 1990a, 1992 and May et al., 1992). 

TABLE 10.12 Concentrations of 10 PAHs in National Institute of Standards and Technology (NIST) Standard Reference Material SRM 1649 Air Particles Determined by Dual Programmable Fluorescence Detector Method... 

Li, X., Coles, B.J., Ramsey, M.H. and Thornton, I. (1995b) Chemical partitioning of the new NIST standard reference materials (SRM 2709-2711) by sequential extraction using ICPAES. Analyst, 120, 1415-1419. 

In contrast, NIST Standard Reference Material SRM 1939 from Hudson River sediment in New York state had an EF of 0.7 for PCB 95 (Equation (4.4) on Chirasil-Dex) [70]. Similar nonracemic residues were reported for PCBs 95,136,149,174, and 183 in this SRM [106]. These sediments are heavily contaminated with PCBs from historical releases from the General Electric capacitor plant in Schenectady, New York. Microbially mediated biotransformation of PCBs has occurred in these sediments by both anaerobic reductive dechlorination [155] and aerobic oxygenase and dioxygenase activity [153]. A subsequent. 

NIST standard reference material, SRM 660 (see http //srmcatalog.nist.gov/). 

Schantz MM, Parris RM, Wise SA. 1993b. NIST standard reference materials (SRMs) for polychlorinated biphenyl (PCB) determinations and their applicability to toxaphene measurements. Chemosphere 27(10) 1915-1922. 

Work is underway to standardize the test method described here as a new ASTM standard. An Inter-Laboratory Study (ILS) is proposed to include at least nine each of gasoline and diesel Tier 2 class materials containing sulfur levels between <10 and 80 mg/kg in gasoline and between <10 and 80 mg/kg in diesels. Some blind National Institute of Standards and Technology (NIST) Standard Reference Materials (SRM) and solvent blanks are also plaimed for the cross check. The ILS will follow a protocol of an initial analysis of a set of samples and solvent blanks, and after an elapsed time of at least 12 h but no more than 72 h, a second set of measurements on the same set of samples and blanks will be completed. We expect this ILS to be completed by the end of2005. 

Environmental applications of ICP-MS are numerous, and include analysis of water, wastewater, soil, sediment, air particulates, and so on. A typical environmental analysis is to determine the leachable metals from soil or sediment the sohd is not dissolved but leached or extracted to determine labile elements. These labile or leachable elements are the ones that might be mobilized from a landfill into a drinking water supply, for example. Figure 10.39 gives an example of determining leachable metals from an NIST Standard Reference Material (SRM) soil sample by ICP-MS. 

The DSC peak area must be calibrated for enthalpy measnranents. The same types of high-purity metals and salts from NIST discnssed for the calibration of DTA eqnipment are also used to calibrate DSC instruments. As an example, NIST standard reference material (SRM) 2232 is a 1 g piece of high-purity indium metal for the calibration of DSC and DTA eqnipment. The indium SRM is certified to have a tanperature of fusion eqnal to 156.5985 C 0.00034 C and a certified enthalpy of fusion eqnal to 28.51 0.19 J/g. NIST offers a range of similar standards. These materials and their certified valnes can be found on the NIST website at www.nist.gov. Government standards organizations in other countries offer similar reference materials. 

TABLE 1. Compiled Data for NIST Standard Reference Material (SRM) ... 

Weidner, V. R., Barnes, P. Y., and Eckerle, K. L. (1986). A wavelength standard for the near infrared based on the reflectance of rare-earth oxides. J. Res. Natl. Bureau Standards 91, 243. Origin of NIST standard reference material SRM 1920 [wave cals). 

Analysis of Standards The analysis of a standard containing a known concentration of analyte also can be used to monitor a system s state of statistical control. Ideally, a standard reference material (SRM) should be used, provided that the matrix of the SRM is similar to that of the samples being analyzed. A variety of appropriate SRMs are available from the National Institute of Standards and Technology (NIST). If a suitable SRM is not available, then an independently prepared synthetic sample can be used if it is prepared from reagents of known purity. At a minimum, a standardization of the method is verified by periodically analyzing one of the calibration standards. In all cases, the analyte s experimentally determined concentration in the standard must fall within predetermined limits if the system is to be considered under statistical control. 

National Institute of Standards and Technology (NIST). The NIST is the source of many of the standards used in chemical and physical analyses in the United States and throughout the world. The standards prepared and distributed by the NIST are used to caUbrate measurement systems and to provide a central basis for uniformity and accuracy of measurement. At present, over 1200 Standard Reference Materials (SRMs) are available and are described by the NIST (15). Included are many steels, nonferrous alloys, high purity metals, primary standards for use in volumetric analysis, microchemical standards, clinical laboratory standards, biological material certified for trace elements, environmental standards, trace element standards, ion-activity standards (for pH and ion-selective electrodes), freezing and melting point standards, colorimetry standards, optical standards, radioactivity standards, particle-size standards, and density standards. Certificates are issued with the standard reference materials showing values for the parameters that have been determined. 

Physical or artifactual standards are used for comparison, caUbration, etc, eg, the national standards of mass, length, and time maintained by the National Institute of Standards and Technology (NIST) or the standard reference materials (SRMs) collected and distributed by NIST. Choice of the standard is determined by the property it is supposed to define, its ease of measurement, its stabiUty with time, and other factors (see Fine chemicals). 

Some reference material producers/suppliers use different names to describe their materials. For example, a Standard Reference Material (SRM) is a certified reference material issued by the National Institute of Standards and Technology (NIST), while European Reference Materials (ERMs) are CRMs produced under a joint collaboration between three European reference materials producers, i.e. BAM (Federal Institute for Materials Research and Testing, Germany), IRMM (European Commission, Joint Research Centre, Institute for Reference Materials and Measurements, Belgium) and LGC (UK). 

A sample for which the true response is already known or is established is called a standard. A standard can be a primary standard, which is a standard through which other substances or solutions are made to be standards. It can also be a secondary standard, a solution whose concentration is known accurately either because it was prepared using a primary standard or because it was compared to another standard. All standards must ultimately be traced to a standard reference material (SRM). Standard reference materials are available from the National Institute of Standards and Technology (NIST) and should not be used for any other purpose in the laboratory (Section 5.4). Standardization is an experiment in which a solution is compared to a standard in order for itself to be a standard. The solutions used to establish a standard curve are often called reference standards and these must also be traceable to an SRM. 

In the above discussion, standard reference materials (SRMs) were mentioned often. A reference material (RM) is a material or substance suitable for use in calibrating equipment or standardizing solutions. A certified reference material (CRM) that a vendor indicates, via a certificate, is an RM. A standard reference material (SRM) is one that is distributed and certified by a certifying body, such as NIST. The SRM is the material to which all calibration and standardization materials should be traceable. A standard material becomes one when it is compared to or prepared from another. Ultimately, it all rests on the SRM — meaning all standard materials are traceable to an SRM (see Figure 5.10). 

Several organizations (e.g., NIST, NRC-Canada, and IAEA) provide sediment reference materials containing radionuclides, many of which are only certified for artificial radionuclides ( Cs, Sr, Am, and Pu). Certain specific radionuclides have no certified natural matrix materials, including ocean, lake, and river sediments. Although these sediments are certified for a few naturally occurring and artificial radionuclides, the extent of radioactive equilibrium of the uranium and thorium decay series in these environmental materials is not provided. NIST currently offers an ocean sediment Standard Reference Material (SRM 4357) in... 

Standard reference material (SRM) for wavelength accuracy, stray light, resolution check, and photometric accuracy can be purchased from NIST. Certified reference materials (CRMs) which are traceable to NIST and recertification services can be purchased from instrument manufacturers and commercial vendors [12]. The cost of neutral-density filters and prefabricated standard solutions in sealed cuvettes can be substantial. When purchasing performance verification standards from a secondary supplier other than a national standard organizations such as NIST in the United States and National Physical Laboratory (NPL) in the United Kingdom, make sure that the traceability of the standards are available in the certificates. The traceability establishes the relationship of individual results to the national standard through an unbroken chain of comparisons. 

SRM 979), Ni (nickel metal isotopic standard NIST SRM 986), Rb (rubidium chloride isotopic standard NIST SRM 984) and Sr (strontium carbonate isotopic standard NIST SRM 987). In addition, isotope reference materials are available for heavy elements such as T1 (thallium metal isotopic standard NIST SRM 997), Pb (NIST lead standard reference materials SRM 981-983) or U (uranium oxide NIST isotope standard U 005, U020, U350, U500 or U930) and others. The most important isotope standard reference materials applied in inorganic mass spectrometry are summarized in the table in Appendix V.17... 

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... 

Chemical Analyses. Subsamples (<20 mg) of standing-crop-trap particulate matter were solubilized by acid digestion in sealed all-Teflon bombs (Bombco Inc.) in a procedure modified from Eggiman and Betzer (13). National Institute of Standards and Technology (NIST) standard reference materials River Sediment (SRM 1645), Urban Particulate Matter (SRM 1648), and mixed-element liquid spikes were used to check bomb performance. 

Tests on glass standard reference materials (SRM) from the National Institute of Standards and Technology (NIST) show that a stable signal is obtained when each isotope is measured using the peak jumping mode and one point per peak with a dwell time of 18,000 ps. The quadrupole mass spectrometer scans the entire mass range three times per replicate and accumulates 9 replicates for a total acquisition time of about 1 minute. For this application, fifty-three isotopes were selected (Table I). 

In our experiments crystalline bovine serum albumin from Fluka, cat.no. 05470, (FLUKA albumin) was used for calibration and traceability purposes. The Fluka product was tested for traceability against the National Institute of Standards and Technology (NIST), USA Standard Reference Material (SRM) 927c (Total Protein Standard) bovine serum albumin (NIST albumin). Two different statistical techniques were used to evaluate traceability of the FFUKA albumin to the NIST albumin. 

---