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Acknowledgment
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is obtained. This occurs when the di agonal elements of a covariance ma trix reach a minimum value. If some suitable function of the diagonal ele ments of the covariance matrix is monitored as a function of initial esti mates for the various components, a variance surface is obtained. Results from previous fits can be used to pre dict new initial estimates. Several al gorithms have been developed that al low surfaces not easily described by a model to be searched for optimal val ues. Simplex optimization is the ap proach most familiar to chemists. The technique has worked well in the quantification of uranyl, nickel, and cobalt ions in the presence of un known copper and in the determina tion of cobalt ion in the presence of unknown copper, nickel, uranyl, and picrate ions. Future articles in this series will ex plore some of these techniques in greater depth. However, Part II of this article, October 1985, will open up an other drawer in our electronic toolbox, exploring the hardware that imple ments some of these new software tools and arrays of specific and non specific detectors.
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NEWS from the
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The author wishes to thank Hank Wohltjen of the U.S. Naval Research Laboratory and Mark Wingerd, Chemistry Department, VPI & SU, for their help in focusing on several of the items in the electronic toolbox. Deep appreciation is extended to those who shared reprints, preprints, and inter nal reports with the author.
References Ask for any of these FREE HPLC Lab Reports:
METHOTREXATE I N SERUM ANIONS Ask for details on this or other pioneering HPLC Applications from Kratos Call or Write:
KRATOS A N A L Y T I C A L MHbL'fHQS 170 Williams Drive · Ramsey. N.J. 07446 Telephone: 201/934-9000 · Telex: 6853505 CIRCLE 122 ON READER SERVICE CARD
1202 A · ANALYTICAL CHEMISTRY, VOL. 57, NO. 11, SEPTEMBER 1985
(1) Hirschfeld, T. Energy Tech. Rev. Feb. 1984, pp. 16-19. (2) Ibid., pp. 20-23. (3) a. Wohltjen, H.; Dessy, R. E. Anal. Chem. 1979, 51, 1458-75; b. Wohltjen, H. Sensors and Actuators 1984, 5, 307-25; c. Groetsch, J. Α.; Dessy, R. E. J. Appl. Polym. Sci. 1983, 28,161-78. (4) Bolster, R. N.; Wohltjen, H. NRL Re port 5451, Sept. 28,1984. (5) Wohltjen, H.; Barger, W.; Snow, Α.; Jarvis, N. L. IEEE Trans. Electron. De vices 1985, 32 (7). (6) Janata, J., presented at the 4th Scien tific Session on Ion-Selective Electrodes, Matrafured, Hungary, Oct. 8-12, 1984. (7) Lundstrom, I. In "Chemically Sensitive Electronic Devices, Principles and Appli cations"; Zemel, J.; Bergveld, P., Eds.; Elsevier Sequoia: Lausanne, Switzerland, 1981; pp. 403-26. (8) Burgess, Lloyd W. "A Fiber Optic In terferometer for Enthalpimetric Sensing in a Flowing Stream," Dissertation, VPI & SU, 1984. (9) Guiliani, J. F.; Wohltjen, H.; Jarvis, N.L. Opt. Lett. 1983,8, 54-56. (10) Arney, L., personal communication. (11) Binkley, D. P.; Dessy, R.E. Anal. Chem. 1980,52, 1335-44. (12) Lam, R. B.; Foulk, S. J.; Isenhour, T. L. Anal. Chem. 1981,53,1679-84. (13) Ishihara, F., personal communication. (14) Brown, T. F.; Caster, D. M.; Brown, S.D. Anal. Chem. 1984,56,1214-21.
