FLOW-INJECTION ANALYSIS FOR HYDROGEN-PERO XIDE USING A TITANIUM(IV)-PORPHYRIN COMPLEX

A sensitive flow-injection analysis using the Ti-TPyP reagent was deve loped for the determination of trace amounts of hydrogen peroxide. The reagent, which is an acid solution containing oxo[5, 10, 15, 20-tetra (4-pyridyl)porphyrinato]titanium(IV) {TiO(tpypH4)4+}, reacts with hydr ogen peroxide to form a monoperoxo complex {TiO2(tpypH4)4+}, which exh ibits an absorption maximum at 450 nm. A flow-injection manifold compr ises two channels system. The molar absorptivity (epsilon) of the comp lex was found to be 1.1 X 10(5) M-1 cm-1. The absorbance was measured as the peak height in the FIA system. The linear response was obtained over the range of 1 X 10(-8) approximately 1 X 10(-5) M hydrogen pero xide and the detection limit was 5 X 10(-6) M for a 100 mul sample inj ection. The method was used to analyze 30 samples per hour, the result s were accurate with a relative standard deviation of 0.97 % for the i njection of 1 X 10(-6) M hydrogen peroxide (n = 10). The concentration of hydrogen peroxide in rainwater samples collected in Tokyo area (Ha chioji) was determined by this method over the range of 7 X 10(-7) app roximately 4.3 X 10(-5) M.