Method of quantitatively measuring an oxidative substance using

Abstract

Disclosed herein is a method of quantitatively measuring an oxidative substance with avoiding influences of a coloring-interfering substance in the quantitative measurement of the oxidative substance by using a triphenyl methane type leuco coloring matter as a coloring reagent. Disclosed herein is also such an oxidative quantitative measurement in which the coloring sensitivity can be further adjusted. In order to avoid the influences of the coloring-interfering substance, there is employed at least one kind of (i) uricase, (ii) an anionic surface active agent and (iii) a metal chelate compound. As the triphenyl methane type leuco coloring matter, use may be made of a compound of the general formula (I): ##STR1## wherein R.sub.1, R.sub.2, R.sub.3 and R.sub.4, which may be the same as or different from one another, represent a hydrogen atom or a lower alkyl group, and X.sub.1 and X.sub.2, which may be the same as or different from each other, represent a hydrogen atom, --SO.sub.3 M.sub.1, --COOM.sub.2, --O(CH.sub.2).sub.m SO.sub.3 M.sub.3, --O(CH.sub.2).sub.n COOM.sub.4 or --N(R.sub.5) (R.sub.6) in which M.sub.1, M.sub.2, M.sub.3 and M.sub.4 represent a hydrogen atom, an alkali metal ion or NH.sub.4.sup.+, R.sub.5 and R.sub.6 independently represent a hydrogen atom or a lower alkyl group, and m and n represent an integer of 2-4. Azide compound is further added or the compound represented by the general formula (I) is included with cyclodextrin or modified dextrine to adjust coloring sensitivity.