Anal. Chem. lQ86, 58, 2258-2265
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While further studies are necessary to identify the exact mechanism for the decomposition of allyldiisopropylamine oxide, the present study has shown the value of combining a capillary flow system with high-pressure FTIR spectrometry for reaction monitoring. Other spectroscopic techniques may be adaptable to similar measurements, as indicated by the recently reported combinations of capillary SFC with a mass spectrometer (17)or a photodiode array system (18). In addition, the setup described in this communication may represent the smallest flow injection analysis (8)system reported to date.
ACKNOWLEDGMENT The authors acknowledge Jahangir Emrani and Joseph Gajewski of this department for helpful discussions and the samples of allyldiisopropylamine oxide. We also thank Sharon Smith and Dennis Gerson of IBM Instruments, Danbury, CT, for helpful discussions and technical assistance. Registry No. I, 102725-56-4. LITERATURE CITED (1) Squires, T. G.; Renier, C. G.; Aida, T. Fluid Phase Equilib. 1983. 10, 26 1-268. (2) Llphard, K. G.; Schneider, G. M. J. Chem. Thermodyn. 1975, 7 , 805-814.
Mlchels. A.; Kleerkoper, L. Physica (Amsterdam) 1939, 6 . 586-590. Novotny, M.; Springston. S.R.; Peaden. P. A.; Fjeldsted, J. C.; Lee, M. L. Anal. Chem. 1981, 5 3 , 407A-414A. Shafer, K. H.; Griffiis, P. R. Anal. Chem. 1983, 55, 1939-1942. Olesik, S. V.; French, S.B.; Novotny, M. Chromatographia 1984, 78,
489-495. French, S.E.; Novotny, M. Anal. Chem. 1986, 58, 164-166. Ruzicka, J.; Hansen, E. L. "Flow Injection Analysis", in Chemical Analysis; Eking, P. J., Winefordner, J. D., Eds.; Wiley: New York, 1981;Vol. 62. Optical and Infrared Detectors; Keys, R. J., Ed.: Springer-Verlag: Berlin, 1977. Schoenmakers, P. J. J. Chromatogr. 1984, 315, 1-18. Barbon, A. F. M. Chem. Rev. 1975, 75, 731-753. IUPAC International Thermodynamic Tables of the Fluid State, Carbon Dioxide; Pergamon Press: Oxford, 1976. Cukenor, C. C. J. Rev. Pure Appl. Chem. 1953, 3 , 83-114. Emrani, J.; Gajewski, J. J., Department of Chemistry, Indiana University, private communication, September 1984. Dack, hi. R. J. J . Chem. Educ. 1974, 51, 231-234. Schoenmakers, P. J.; Billiet. H. A. H.; de Galan, L. Chromatographla 1982. 15. 205-214. Smith, R.'D.; Felix, W. 0.;Fjelsted, J. C.: Lee, M. L. Anal. Chem. 1982. 54. 1883-1885. (18) Gluckman. J.; Shelly, D.; Novotny, M. Anal. Chem. 1985, 57,
1546-1552.
RECEIVED for review November 27,1985. Accepted April 14, 1986. These investigations were supported by Grants N1482-K-0561from the Office of Naval Research and NSF CHE 82-00034 from the National Science Foundation.
Versatile Automatic Development System for Flow Injection Analysis D. Betteridge,*' Timothy J. Sly, and Adrian P. Wade' Department of Chemistry, University College of Swansea, Singleton Park, Swansea SA2 8PP, United Kingdom
Derrick G. Porter Department of Trade and Industry, Laboratory of the Government Chemist, Cornwall House, Stamford Street, London SEI 9NQ, United Kingdom
A computer-controlled automatic analyzer has been developed to facliltate the rapid development of novel analytical methods based on flow injection analysis (FIA) through the use of mathematlcal technlques such as modified simplex optbnlzation. The apparatus abws varlatkn of ?low rates, pH, and reagent concentration In one or more sample or carrier streams and can accommodate spectrophotometrlc or electrochemical detectors. The system software, wrltten in BASIC, is menu-drhren and interactive. It Includes a modifled slmplex opthrlzaUon procedure that has pennmed automated optlmlzatlon of analytical methods, yieldlng an improvement In sensitivity equal to that obtalned In earlier manual experiments. The results obtained are discussed, as are the design and execution of the apparatus and software.
One of the crucial problems of automatic analysis is how to speed up or automate the development of an automated method or system. The difficulty is especially acute if one Present address: BP Research Centre, Chertsey Rd, Sunburyon-Thames TW16 7LM, UK.
has such diversity of workload that an automatic method needs to be up and running quickly and is subsequently discarded after a month or so of intensive use. Flow injection analysis (FIA) systems (1-3) afford a means of studying the general problem in a concrete way; they are versatile, easy to configure, have a rapid response, and can simulate many other systems. However, in developing a method based on even a simple FIA system, one may need to adjust five or more variables in order to establish optimum conditions for the analysis. This can be very time-consuming if a conventional univariate optimization is undertaken manually, and indeed where interactions exist between the variables, one is unlikely to find the true optimum ( 4 ) . One solution to this problem would lie in the use of an automated instrument, in which the experimental conditions of concentration, flow rate, pH, etc. may be varied according to a preprogrammed pattern under computer control. The ability to control the system parameters in this way would allow a conventional univariate optimization to be performed much more quickly than is possible by manual means. In this approach, however, the number of experiments to be performed is still extremely large (4). A more economical scheme would be to use the automatic control facilities to carry out a modified-simplex optimization (5,6). This optimization
0003-2700/86/0358-2258$01.50/0 0 1986 American Chemical Society
ANALYTICAL CHEMISTRY, VOL. 58, NO. 11, SEPTEMBER 1986
procedure is faster and more reliable than a univariate approach and has been applied successfully to the development of several new analytical methods based chemiluminescence (6) FIA (4, 7,8). When performed manually, a significant proportion of the experimental time for any optimization procedure is spent in preparing solutions and adjusting the apparatus, and this can be greatly reduced by automation, with the added advantage that the operator is freed for other work. The aim of this study was to develop a versatile, general purpose FIA instrument under full computer control that could be used in conjunction with a suitable simplex optimization program in order to develop new FIA methods reliably, in the minimum time, and with a minimum of manual intervention-in other words, an automated development system. Methods developed using such an instrument could be either implemented directly on the development system itself, where the method was to be used for a limited period only, or transferred to standard FIA apparatus for long-term routine use. The design strategy adopted for the whole system was based upon the use of separate, versatile items of hardware and software that could be quickly and easily rearranged to cope with a wide range of applications, rather than a dedicated automatic analyzer, which could only be used for one particular type of method development (such as the system used by Stieg and Nieman (6)). There is no reason, for instance, why the system could not be used for the development of methods based on air-segmented continuous flow analysis, with a suitable manifold, or indeed any type of analytical procedure involving the use of flowing liquids a t low pressure (
