that manufactured goods represent approximately 40% of the U.S. GNP {4). Furthermore, the anecdotal information provided above indicates some of the ties between chemical measurement and product reliability. Better understanding of this link should help to improve competitiveness and productivity. A conservative estimate of the number of chemical analyses that are repeated in the analytical laboratory today because of suspected contamination, interference, or poor result is 1 in 10. With a conservative estimate of 250 million chemical measurements per day in the United States, at a cost of $50 billion annually, repeat analyses therefore represent 25 million measurements per day at a cost of $5 billion annually. At our current level of sophistication, we cannot fully correlate chemical composition with product performance and functional characteristics. In industries in which chemical composition is already tied to product performance, it has been estimated that as many as 30% of the samples must be retested. If one assumes that this relationship holds constant in the future, the cost of repeat analyses alone would be $15 billion annually or nearly 0.5% of the GNP. A recent estimate for U.S.-manufactured goods indicated that 10-20% of
domestic sales are for "off-spec" products—manufactured goods sold at a loss or reprocessed to meet specifications (5). Because manufactured goods represent 40% of the GNP, off-spec products represent 4-8% of the GNP. Of course, one cannot conclude that chemical analysis would prevent the manufacture of off-spec goods, but by considering the two cases just presented, it can be estimated that between 0.5 and 8% of GNP is directly affected by the quality of chemical measurement. Even 8% is probably a conservative estimate of the overall impact of chemical measurements on U.S. productivity, because the total impact also includes measurements that qualify or reject feedstock and process streams, resulting in high-quality products. Certainly as the state of chemical measurement improves and as relationships between chemical composition and product performance are better understood, the impact of quality chemical measurement on U.S. productivity will increase. Laboratory of the future If one accepts these arguments, one can speculate on how measurements will be made in the laboratory of the future. Laboratory efforts would begin with the accurate measurement of a chemical constituent known to be important
to product performance. The concentration of that constituent would then be varied and the impact on product performance determined. By ascertaining the concentration level at which product performance suffers, one could then set accuracy and precision goals for measuring that constituent in feedstocks, intermediates, and final product. Thus performance characteristics for the product and measurement goals for the chemical and physical testing laboratories could be established simultaneously. Productivity would be maximized both in manufacturing and in the cost-effective quality assurance program in the chemical laboratory. A discussion of measurement in the future would be incomplete without stating that the laboratory of the future will be closer to the actual production process. Developing more sophisticated chemical sensor technology and providing more immediate feedback to the process stream controller will result in greater use of in-process measurements in industry. The laboratory of the future will also have a number of analytical aids now being developed to assist in the generation of quality data and to enhance the productivity of the laboratory. The first major contributors will be expert systems capable of providing informa-
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. . . and this Is lust Urn beginning. 78 A · ANALYTICAL CHEMISTRY, VOL. 60, NO. 2, JANUARY 15, 1988
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