A new red-region substrate, tetra-substituted amino aluminium phthalocyanine, for the fluorimetric determination of H2O2 catalyzed by mimetic peroxidases

A new red-region fluorogenic substrate, tetra-substituted amino aluminium p hthalocyanine, was developed for the selective determination of H2O2 based on the catalytic effect of mimetic peroxidases, viz., hemin or iron tetrasu lfonatophthalocyanine (FeTSPc). Under the optimum conditions, the linearity of the calibration graph for the determination of H2O2 with hemin (or FeTS Pc) as the catalyst was in the range from 0.0 to 3.0 X 10(-7) mol L-1 (or f rom 0.0 to 2.0 x 10(-6) mol L-1). The detection limits were 3.7 X 10(-9) an d 4.9 x 10(-9) mol L-1 H2O2, respectively. The relative standard deviation (n = 7) was within 1.5% in the middle of the linear range. The peroxidase a ctivity of the mimetic enzymes hemin and FeTSPc, the effects of some experi mental conditions and the influence of foreign substances were investigated . With this substrate, 0.0-7.5 x 10(-8) mol L-1 hemin and 0.0-2.0 x 10(-6) mol L-1 FeTSPc can be determined with an accuracy and precision of about 1. 3%. The potential application of the reagent was tested by the determinatio n of H2O2 in rainwater.