Editors' Column
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Standard Reference Materials As one attempts to determine elements in substances down to the ppm, ppb, and sub-ppb levels, standards become extremely important. The need for trace element analysis is clearly pointed up by Federal regulations that deal with the amounts of elements permissible in our food (FDA), air and water (EPA), and in the industrial working environment (OSHA). Analytical Chemistry has given this subject a lot of attention, not only in our technical section, but also in the Report and Instrumentation articles. A quick glance at this month's contents page shows original research articles dealing with zinc and cadmium, wear metals, cobalt, nickel and antimony, lead, rare earths, and trace elements in airborne particulate matter, with techniques such as RF source spectrometry, plasma jet arc spectrometry, polarography, cathodic stripping, emission spectrometry, etc. In addition, our Report this month describes the development of the atomic absorption spectrophotometer, an important instrument in trace metal determination. The National Bureau of Standards recognizes the importance of standards that labs can use to check their own trace analytical methods and of the general area of trace analysis. They are sponsoring a symposium on Accuracy in Trace Analysis (Sampling, Sample Handling, and Analysis), October 7 to 11, 1974, in Gaithersburg, Md. Also, under development in their Standard Reference Materials program, but not yet available, are SRM's 1632, 1633, and 1634 which will provide standards for trace elements in coal, fly ash, and fuel oil, respectively.
Benchmark Standards So-called "benchmark" standards are planned to serve as anchor points for the calibration of many instrument measurement systems. Because many of these methods are matrix dependent, standard materials in different classes of substances are needed. Thus, the Bureau has SRM's in metal (iron and steel standards); trace-element glasses; and organic
matrices (orchard leaves and bovine liver). In the planning stages at NBS are metal matrices: copper, aluminum, and superalloys; inorganic matrices: burnt refractories, selected ferroalloys, and fertilizers; and organic matrices: alfalfa, tomato leaves, aspen chips, citrus leaves, pine needles, serum albumen, carbohydrates, bone, and tuna fish. Work is now proceeding on SRM's 610 through 617, trace elements in a glass matrix, which are being characterized for use as benchmark standards. Other standards under development are SRM 1641, 1642, mercury in water; SRM's 1636 through 1638, lead in gasoline; SRM 143c, cystine, microchemical standard for C, H, N, and S; and copper benchmark standards. A copy of "NBS Trace Element Standard Reference Materials," is available on request.
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Clinical Standards
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W. Wayne Meinke, past chief of the Analytical Chemistry Division at NBS, wrote a Report for Analytical Chemistry on clinical standard reference materials in the May 1971 issue, page 28 A. New standards available in the clinical area since that time include SRM's 919, sodium chloride; 920, D-mannitol; 921, Cortisol; 924, lithium carbonate; and 925, VMA (4-hydroxy-3-methoxymandelic acid). In preparation are SRM's 926, 927, and 928, bovine-serum albumin powder, bovine-serum albumin (7% solution), and lead nitrate, respectively. The Bureau has a 12-page "Coordinators Report" which contains upto-date information on all new SRM's available, those coming this year, and those in process or planned. This report has been compiled by R. E. Michaelis, T. W. Mears, W. P. Reed, and C. L. Stanley. Copies are available on request. All inquiries concerning NBS reference materials should be sent to the Office of Standard Reference Materials, Room B311, Chemistry Bldg., National Bureau of Standards, Washington, D.C. 20234. Josephine Petruzzi
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A N A L Y T I C A L CHEMISTRY, VOL. 46, NO. 8, JULY 1974 • 737 A
