A MODEL FOR MECHANISM OF PEROXYOXALATE CHEMILUMINESCENCE AS APPLIED TO DETECTION IN LIQUID-CHROMATOGRAPHY

In recent years, a substantial body of knowledge has been accummulated on the mechanism of peroxyoxalate chemiluminescence (PO-CL). Formal m echanisms have been reported previously by the authors and others purp orting to account for the effects of variation of the primary reagents (concentration of oxalate, hydrogen peroxide, and fluorophore) on the peroxyoxalate induced detection of analytes in liquid chromatography and flow injection analyses. In this article, new pathways are suggest ed also for the induced decomposition of the chemiluminescent intermed iate, including: (a) its reaction with a quencher, and (b) its reactio n with hydrogen peroxide. Quantitative relationships are derived and e stablished for the effect of pH on the maximum light intensity and the rate of the light decay. The parameters extracted from the experiment al data are utilized to predict the influence of reagent concentration s and flow rates on the chemiluminescent detector response. In contras t to the Linearity of the relationships in the static solution studies , significant nonlinearities are presented, based on simulations of ex perimental conditions for flow systems. Among the several conclusions reached, the most important is that the location of the maximum chemil uminescent response in flow systems may not be accomplished by simply determining the optimal values for the individual parameters.