pH and concentration response surfaces for the luminol—H2O2 electrogenerated chemiluminescence reaction

A response surface for the luminol-H2O2 electrogenerated chemiluminescence (ECL) reaction is constructed by systematically altering the pH and reagent concentration while determining luminol or H2O2. Ranges covered are 0.5 through 500 μMH2O2 and pH 7 through 10 for luminol determinations and 0.1 through 1000 μ M luminol and pH 7 through 10 for H2O2 determinations. At a given luminol or H2O2 concentration the ECL response surface with respect to pH and reagent concentration is essentially identical in general shape to the response surface observed at any other concentration. With this information one can predict the change in ECL response between any two sets of conditions or maintain the same ECL response with two sets of conditions if appropriately chosen. In general, monotonically sloping contours are observed such that as the pH or the luminol or H2O2 concentration is increased, there is a corresponding increase in ECL response.