EDI7ORlAL
Trace of a Trace of a Trace (Analysis) Trace analysis has meant the detection and determination of impossibly tiny quantities of elements and molecules ever since I became a student of analytical chemistry. With persistent research, analytical chemists over the years have gotten better and better at trace analysis, and both selectivity and detection limits for almost anything you care to name have steadily gone down. These improvements have occurred both by refinements of existing principles of measurement and by invention of new ones. Still, judging by both basic and applied current publication activity, and by the constant discussion at professional meetings of the need for improvements, trace analysis remains a frontier area of our discipline and seems destined to be one for years to come. Why is trace analysis such a persistently important part of analytical chemistry? Surely one component is that analysis of small quantities offers one of the most pervasive intellectual challenges found in analytical chemistry. To t h e analytical researcher, the goal of lowering the concentration or quantity value with which a chemical species can be determined is almost a matter of principle. It's what the successful analytical chemist does. Professors teach their students about new principles of trace analysis with special enthusiasm, seeking to catch the imagination of our future analytical chemistry scholars. Analytical chemistry furthermore finds itself increasingly entwined with other disciplines that demand small-quantity analysis; for example, the Human Genome Project calls for new measurement principles that are simultaneously satisfactory in trace-level sensitivity, specificity, speed, and cost. The pure intellectual challenge of trace analysis is a magical part of analytical chemistry, and it is at the core of our discipline. There is also the equally important, realworld interest in achieving more and more sensitive analytical measurements. The practical objectives have been of two kinds, the more long-standing one being that of providing the chemical composition information that industry needs to make a bet-
ter product or process. Industrial sectors such as microelectronics, automotive, communications, and aerospace comprise an increasing p a r t of t h e trace analysis equation. The practical needs for determinations of trace quantities of t a r g e t substances in specific matrices, with constraints of economy and speed, seem destined to continue to grow in diversity as the technology of our society becomes more complex. This diversity will require ingenuity and imagination of the highest order, in part because so many trace analysis needs are becoming vested in industries that traditionally have not required substantial chemical expertise. The continual emergence of new and different practical needs for trace analysis is a wonderfully challenging component of analytical chemistry. Other, more recent, needs for practical trace analysis are driven by government regulations and societal pressure. Trace analysis now has a significant global role in health care, protection of the environment, illegal substance regulation, and monitoring of waste materials, as well as many other concerns. These diverse areas contain opportunities for the thoughtful chemist's societa1 contributions as well as challenges of new dimensions for improved trace analysis. New regulations and public concerns have greatly enriched the science of trace analytical measurements over the past two decades. The challenge of regulation-driven trace analysis research is undoubtedly here to stay. It is therefore important to appreciate that the boundaries of the trace analysis frontier are fixed by an amalgam of political, societal, scientific, and economic factors. This may mean that regulated trace-level target concentrations of a given substance may undergo abrupt changes, or even be deregulated, as a result of unforeseen changes in the political climate. This is an aspect of trace analysis with which the analytical community is likely to become more familiar in years to come.
ANALYTICAL CHEMISTRY, VOL. 63, NO. 19, OCTOBER 1, 1991
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