' eρ ο r t / .
(5) Beck, C. M„ 11. Anal. Chem. 1991, 63, 933 A (6) Burns, D. T. Fresenius J. Anal. Chem. 1993,347,14. (7) Sutton, F. A Systematic Handbook of Volu metric Analysis, 10th ed. (revised by W. L. Sutton and A. E. Johnson); P. Blakiston's Son: Philadelphia, 1911. (8) S. Popoff, Quantitative Analysis, 2nd éd.; P. Blakiston's Son: Philadelphia, 1927. (9) Snell, F. D.; Snell, C. T. Colorimetric Methods of Analysis, 2nd éd.; Van Nostrand: New York, 1936; Vols. I and II. (10) Kolthoff, I. M. Chem. Weekblad 1915,12, 644. (11) Kolthoff, I. M.; Sandell, Ε. Β. Textbook of Quantitative Inorganic Analysis, 3rd éd.; Macmillan: New York, 1952. (12) Braun, T.; Bujdoso, E. CRC Crit. Rev. Anal. Chem. 1982,113, 223. (13) Braun, T. Fresenius Z. Anal. Chem. 1986, 323,105. (14) Locke, D. C; Grossman, W.E.L. Anal. Chem. 1987,59,829 A. References (15) Murray, R W. Talanta 1989,36,11. (16) Walters, J. P. Anal. Chem. 1991,63, (1) A History ofAnalytical Chemistry, Laitinen, 977A1077A1179A. Η. Α.; Ewing, G. W., Eds.; American (17) Ruzicka, J.; Hansen, E. H. Anal. Chim. Chemical Society, Division of Analytical Acta 1975, 78,145. Chemistry: Maple Press: York, PA, 1977. (18) Hansen, E. H.; Ruzicka, J. /. Chem. Educ. (2) Laitinen, H. A. Talanta 1989,36,1. 1979,56,677. (3) Kolthoff, I. M. /. Electrochem. Soc. 1971, (19) Meyerhoff, M.; Kovach, P. M. /. Chem. 118, 5C. Educ. 1983,60,766. (4) Kolthoff, I. M. Am. Lab., May 1979, p. 42. (20) McClintock, S. A; Weber, J. R; Purdy, W. C. /. Chem. Educ. 1985, 62, 65. (21) Rios, A; Luque de Castro, M. D.; Valcarcel, M. / Chem. Educ. 1986, 63, 552. (22) Keller, J. W.; Gould, T. F.; Aubert, Κ Τ. /. Chem. Educ. 1986,63, 709. (23) Stults, C.L.M.; Wade, A. P.; Crouch, S. R /. Chem. Educ. 1988, 65,645. (24) Stults, C.L.M., etal. /. Chem. Educ. 1989, 66,1060. (25) Kneller, P. E.; Anderson, R. M.; Tyson, J.F.AnaLProc. 1989,26,48. (26) Nobrega, J. Α.; Mozeto, Α. Α.; Alberici, R M. / Chem. Educ. 1991, 68, 966. (27) Tyson, J. F. Microchem. J. 1992,45,143. (28) Kowalski, B. R.; Ruzicka, J.; Christian, G. D. Trends Anal. Chem. 1990, 9,8. Produced biennially, the Chem Service Pesticide/ (29) Ruzicka, J.; Christian, G. D. Analyst 1990, 115,475. Metabolite Catalog contains the world's largest (30) Christian, G. D. Analytical Chemistry, 5th selection of pesticide standards. Included in the éd.; John Wiley & Sons: New York, 1994. (31) Berman,RJ.,etal.Mcroc/iem./ 1989, new expanded listing are the first A2LA Certified 39,20. pesticide reference materials available anywhere. (32) Ruzicka, J.; Hansen, Ε. Η. Flow Injection Analysis, 2nd éd.; Wiley Interscience: New All Chem Service pesticide/metabolite standards York, 1988. (33) Taylor, R. H.; Ruzicka, J.; Christian, G. D. are purity certified and expiration dated. Each Talanta 1992,3,285. chemical is cross referenced by generic, trade and (34) Ruzicka, J.; Marshall, G. D. Anal. Chim. Acta 1990,237,329. chemical name, with metabolites listed under their (35) Gtibeli, T; Christian, G. D.; Ruzicka, J. base compound. Anal. Chem. 1991,63,2407.
FIA "titrations" can also be performed (32). In this method, the carrier is the ti trant and contains an indicator. When the sample is injected, equivalency occurs on the rising and falling portions of the re corded signal when passed through a mixing chamber; the width of the signal is proportional to the logarithm of the analyte concentration. Although this proce dure has poorer precision than does vol umetric titrations, a wide range of concen trations can be measured. FLA can also be combined with classical coulometric generation of titrant (33). For the more adventuresome, the new versatile technique of sequential injection analysis (34, 35) can be introduced to students. This technique replaces the in jection valve with a multiport selection valve. Solutions are sequentially aspi rated, under computer control, into the re action coil and then propelled to the de tector. This advanced experiment would be suitable for the instrumental analysis laboratory.
Words of wisdom The quantitative analysis course will con tinue to be important in chemical educa tion. As Lord Kelvin said, "Unless our knowledge can be measured and ex pressed in numbers, it does not amount to much." R. S. Mulliken, 1966 Nobel laure ate, said, "I think it was in a course in quan titative analysis that an appreciation of the scientific method and its rigors began really to take hold of me . . . There were no shortcuts to beat clear thinking, careful technique, and endless patience. Finally, Popoff observed, 'The value of quantita tive analysis to a student... comes in the acquirement of patience, neatness, and ac curacy" (8).
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Analytical Chemistry, September 1, 1995
Gary D. Christian, Divisional Dean of Sciences in the College of Arts and Sciences, performs research in electroanalytical chemistry, atomic spectroscopy, process analysis, and FIA. Address correspondence about this article to him at the Office of the Dean, DS65, College ofArts and Sciences, University of Washington, Seattle, WA 98195.
