FOCUS cal processes. Research areas within CPAC include chemometrics, process chromatography, process control, flow injection, fiber optics, microsensor fabrication, and process analytical instrumentation. CPAC, Kowalski continued, also serves as a clearinghouse for information on analytical methods and a training ground for scientists and engineers skilled in on-line chemical processing, monitoring, and control. (For more information on process analytical chemistry and CPAC, see the REPORT in the May 1, 1987 issue of ANALYTICAL C H E M I S T R Y . )
As is appropriate for a symposium on accuracy in trace analysis, the last two speakers discussed the role of standards in trace analysis. Lloyd Currie of the NBS Center for Analytical Chemistry spoke about the important contributions that chemometrics can make to design, evaluation, and accuracy assurance in multicomponent trace analysis, and Stan Rasberry of the NBS Office of Standard Reference Materials spoke about the role of standard reference materials (SRMs) in the analyst's pursuit of accuracy. Chemometrics, including mathematical modeling, univariate and multivariate statistical analysis, decision and
information theory, and operations research, has some important contributions to make to design, evaluation, and accuracy assurance in multicomponent analysis, said Currie. NBS has a special mission to provide standards for accuracy for all parts of the chemical measurement process, he said, and chemometrics components of this responsibility include assessment of system model and assumption validity; development of consistent nomenclature and scientifically sound formulations with respect to detection, identification, and quantitation; evaluation of the accuracy of algorithms and numerical methods applied to trace analysis data; evaluation of the quality of multivariate data and consideration of standards for reporting such data; and selective generation of standard test data to allow laboratories to monitor the quality of complex data evaluation. SRMs are vital elements in measurement quality assurance, said Rasberry, and are useful in calibration, validation, and especially in determination of accuracy, which is the one thing that seems to worry analytical chemists more than anything else they do. Measurement quality assurance is important in manufacturing, in the service
NO CHARGE? no problem for Zetasizer He In studies of flocculation and colloid stability, the region close to the zero point of charge is the most critical. It is in precisely this region of low mobility that other electrophoresis systems are least accurate and most difficult to use. With its high frequency optical modulator, the Malvern Zetasizer Ik solves this problem, allowing you to measure mobility and zeta potential with uncompromising accuracy right across the range. Measurements are simple, fast and operator-independent and Zetasizer Ik also gives you built-in submicron particle size capability.
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sector, and also to academic and R&D efforts. The SRM program was begun in 1906 with the production of metals SRMs and has now expanded to more than 1000 SRMs, including those for metal alloys; environmental standards such as sulfur in distillate fuel oil; gas mixtures; standards for organic constituents such as PCBs, PAHs, dioxins, and even urban dust; inorganic standards; clinical standards; and instru-
4 ® . · .the use of robotics represents as much as anything the current state of trace analysis in industry. * * mental calibrators. Recent additions include a reference material for aspartame aminotransferase (a precursor to heart attack and liver disease), fat-soluble vitamins in coconut oil, and cholesterol. The types of standards available show a natural progression from commodity materials to environmental materials to clinical materials and finally to nutritional materials with the total-diet SRM. When the last trace analysis conference was held at NBS 10 years ago, it focused almost entirely on environmental issues. But there has been tremendous growth in the field since then, said Donald Johnson, director of the National Measurement Laboratory at NBS. The past 10 years have seen almost an explosion of trace analysis in health, nutrition, and especially in industrial quality assurance, where researchers are attempting to determine the relationship of chemical composition to product performance and industrial quality. Most significant, said Johnson, are the computer applications that have developed over the past several years; computers are now beginning to play a major role in measurement design, optimization, artificial intelligence, and robotics. It is important, he continued, not only to determine where we are now but also to project future needs and determine the directions that this area of science will take over the next 10 years. This symposium certainly accomplished that goal, and by the time the next symposium on trace analysis takes place, many more exciting new advances based on the ideas discussed here will surely be reported. Mary Warner
