Application of rhodamine B hydrazide as a new fluorogenic indicator in the highly sensitive determination of hydrogen peroxide and glucose based on the catalytic effect of iron(III)-tetrasulfonato-phthalocyanine

A sensitive, selective and rapid spectrofluorimetric method is proposed for the determination of hydrogen peroxide using rhodamine B hydrazide as a fluorogenic substrate catalyzed by iron(III)-tetrasulfonatophthalocyanine. It is based on the oxidation of rhodamine B hydrazide, a colorless, non-fluorescent spirolactam hydrazide, by hydrogen peroxide which generates the highly fluorescent product rhodamine B. Under optimum conditions, the responses for hydrogen peroxide were linear from 2.0 × 10⁻⁸ to 2.0 × 10⁻⁶ mol L⁻¹, with a detection limit of 3.7 × 10⁻⁹ mol L⁻¹ in a 3.5 min reaction period. It can easily be incorporated into the determination of biochemical substances that produce hydrogen peroxide under catalytic oxidation in the presence of their oxidase. The possibility has been tested for the determination of glucose in human sera as an example.