analytical chemistry Editor: Herbert A. Laitinen EDITORIAL HEADQUARTERS 1155 Sixteenth St., N.W. Washington, D.C. 20036 Phone: 202-872-4570 Teletype: 710-8220151 Managing Editor: Josephine M. Petruzzi Associate Editor: Andrew A. Husovsky
The Integrated Analytical Operation
Associate Editor, Easton: Elizabeth R. Rufe Assistant Editors: Barbara Cassatt, Deborah M. Cox, Nancy J. Oddenino Production Manager: Leroy L. Corcoran Associate Manager: Charlotte C. Sayre Art Director: John V. Sinnett Artist: Diane Reich Advlsory Board Donald H. Anderson, Edward G. Brame. Jr., Richard P. Buck, Warren B. Crummett, Merle A. Evenson, Velmer Fassel, A. F. Findeis, Robert A. Hofstader, Marjorie G. Horning, Richard S. Juvet, Jr., Lynn L. Lewis, Harry B. Mark, Jr., Walter C. McCrone, Eugene A. Sawicki, W. D. Shults Instrumentation Advlsory Panel: Stanley R. Crouch, Nathan Gochman, Robert W. Hannah, Gary Horlick, James N. Little, Harold M. McNair, David Seligson, R. K. Skogerboe, Donald E. Smith Contributing Editor: Claude A. Lucchesi Department of Chemistry, Northwestern University, Evanston, 111. 60201 Published by the AMERICAN CHEMICAL SOCIETY 1155 16th Street, N.W. Washington, D.C. 20036
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The classical approach to chemical analysis involves a series of distinct operations, including sampling, sample pretreatment, adjustment of conditions, separation, measurement, and data processing. While these distinct steps are still useful for didactic purposes, and often even in practice, there is a pronounced trend towards their consolidation in modern analytical methods. In microprobe methods, the sampling operation is coupled with the measurement step with no intermediate operations. In the spectrophotometric characterization of electrochemical reaction products using transparent electrodes, the sample is generated by an appropriate applied electrical signal, and the-analysis is performed in situ. In chromatographic methods, the essence of the approach has been to achieve a quantitative separation in order to enable the use of nonselective measurement methods. Recent trends have been towards more selective measurements, to decrease the need for complete separations. The ultimate integrated analytical operation is one in which a tentative output signal is used in one or more feed-back loops to direct the acquisition of additional outputs until the desired measurement precision has been achieved. Such integrated analytical operations will become increasingly commonplace as the capabilities of microprocessors become more fully utilized in analytical instruments. As the degree of sophistication increases, the pitfalls facing the unwary analyst become more subtle. It is important therefore to resist the temptation to regard such integrated analytical operations as somehow beyond criticism. Ultimately, the validity of the analysis must be established, as always, through a comparison with standard reference materials of known composition.
Research and Development: Seldon W. Terrant Circulation Development: Marion Gurfein Manuscript requirements are published in the December 1976 issue, page 2297. Manuscripts for publication (4 copies) should be submitted to ANALYTICAL CHEMISTRY at the ACS Washington address. The American Chemical Society and its editors assume no responsibility for the statements and opinions advanced by contributors. Views expressed in the editorials are those of the editors and do not necessarily represent the official position of the American Chemical Society.
ANALYTICAL CHEMISTRY, VOL. 48, NO. 14, DECEMBER 1976
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