Spectrophotometric Determination of Hydrogen Peroxide, Glucose, Uric Acid, and Cholesterol Using Peroxidase-like Activity of an Fe(III) Complex of Thiacalix[4]arenetetrasulfonate Attached to an Anion-exchanger

Abstract

An iron(III) complex of thiacalix[4]arenetetrasulfonate attached to an anion-exchanger (Fe³⁺-TCAS_A-500) showed high peroxidase-like catalytic activity at pH 5 – 8 for the formation of quinoid dye, following the color reaction between 3-methyl-2-benzothiazolinone hydrazone (MBTH) and N-ethyl-N-(3-sulfopropyl)aniline (ALPS) in the presence of H₂O₂. This catalytic activity of Fe³⁺-TCAS_A-500 for the MBTH-ALPS system was applied for the spectrophotometric determination of H₂O₂, glucose, uric acid, and cholesterol. The calibration curves were linear in the concentration range from 1.0 to 15 μg of H₂O₂ in a 1.0-mL sample solution, and from 5.0 to 60 μg of glucose, 2.0 to 30 μg of uric acid, and 11.6 to 116 μg of cholesterol in a 0.5-mL sample solution. The apparent molar absorptivity of H₂O₂ was determined as 2.31 × 10⁴ L mol⁻¹ cm⁻¹, which was about 70% of that by peroxidase under the same conditions. The determination method using Fe³⁺-TCAS_A-500 was applied for the determination of glucose and uric acid in both control sera I and II.