FLOW-INJECTION ANALYSIS USING CONTINUOUS CHANNEL ELECTROPHORESIS

Continuous zone electrophoretic separations in narrow channels coupled to small-bore capillaries have been demonstrated and characterized pr eviously. Presented here is the use of this new technique to monitor d ynamic chemical changes occurring in a flow injection analysis system, The fundamental aspects of the data that this type of separation gene rates are discussed in a comparison of static and dynamic analyses, An analysis of a dynamic separation is also provided to thoroughly outli ne the steps necessary to deconvolute the data, Three types of dynamic analyses, which simulate realistic analytical situations, are then ex amined in detail, The first of these involves the addition of a mixtur e of four dansylated amino acids to the flow injection system to provi de several different sample duration periods, The second is the stagge red addition of short-duration plugs of analyte to the system, The thi rd is the continuous addition of one analyte at different concentratio ns. Quantitative information generated by these experiments includes t he simultaneous determination of the time of analyte contact and its d uration of contact with the sampling capillary, identification of anal ytes based on electrophoretic mobilities, and concentration changes wi th time, For the addition of a 1.52 mM solution of N-epsilon-dansyl-L- lysine, the sample duration and time of analyte contact with the capil lary was determined with an error of <4%. Concentration changes in the FIA system of dansyl-L-arginine over the range of 0.38 -3.04 mM are a lso demonstrated with transitional edges on the time scale of 3-4 s. Q ualitatively, the appearance of analyte bands can reveal impurities an d fronting or tailing effects as seen in conventional capillary electr ophoretic separations, The results demonstrate the ability of the tech nique to successfully probe dynamic environments.