Abstract: There is provided an improved quantitative analysis for the determination of a substrate or enzyme. In the analysis for the enzyme, it is reacted with a known substrate and in the analysis for the substrate, it is reacted with a known enzyme and then the resultant substance is reacted with an oxidase to produce hydrogen peroxide which is then reacted with a peroxidase, phenol derivatie and coupler to form a colored material which is then subjected to colorimetic analysis. The improvement resides in conducting the foregoing process by adding to the test sample a first reagent containing the oxidase, peroxidase and phenol derivative represented by the formula: ##STR1## wherein R.sub.1 is .circle.a a lower alkyl group having one to five carbon atoms or .circle.b the group defined in .circle.a above having a hydroxyl or sulfonic acid group, R.sub.

Abstract: A method for determination of hydrogen peroxide by chemiluminescence analysis which consists of reacting a sample containing hydrogen peroxide with an oxidizable non-fluorescent substance in the presence of an oxidizing catalyst to convert the non-fluorescent substance to a fluorescent substance, reacting the fluorescent substance with an oxalic acid di-ester and hydrogen peroxide in the presence of an inhibitor which inactivates the oxidizing catalyst, and then measuring the amount of light emission produced to determine the amount of hydrogen peroxide contained in the sample. Determination and enzyme immunoassay for a component other than hydrogen peroxide in a sample from living body and evaluation of bactericidal activity in phagocytosis of leukocytes by utilizing this method are also disclosed.