Study on Fluorometric Determination of Hydrogen Peroxide Catalyzed by Iron(III)-Tetrasulfonato-Phthalocyanine with Thiamine Hydrochloride as a Substrate

ABSTRACT

Iron(III)-tetrasulfonatophthalocyanine(FeTSPc) has been used as a mimetic enzyme in the determination of hydrogen peroxide with thiamine hydrochloride as a fluorogenic substrate. The determinations were carried out in both acidic and basic environments, with different limits of detection and linear ranges. In acidic condition, the linear calibration graph was obtained from 5.0x10⁻⁸ mol/L to 8.0x10⁻⁶ mol/L, with a detection limit of 2.1x10⁻⁸ mol/L H₂O₂ when Na₂HPO₄-citric buffer solution (pH 2.8) was used as the reaction medium. It was also found that using one of the three polybasic carboxylic acids such as citric acid, tartaric acid and malonic acid as the catalytic reaction medium can lead to particularly sensitive systems, permitting a detection limit as low as 3.5x10⁻⁹ mol/L H₂O₂; whereas in basic reaction medium (Na₂CO₃-NaHCO₃ buffer solution, pH = 10.0), the linear range of the calibration graph was from 5.0x10⁻⁸ mol/L to 2.0x10⁻⁶ mol/L H₂O₂ with a detection limit of 1.4x10⁻⁸mol/L. The applicability of the method to the determination of glucose in human serum was demonstrated by investigating the recovery of the known glucose added to human serum.

Keywords::

• Mimetic enzyme
• Spectrofluorimetric determination
• Hydrogen peroxide
• Glucose, Thiamine, Iron-tetrasulfonatophthalocyanine