Studies on catalytic spectrophotometry using β-cyclodextrin polymer–Schiff base metal complex as mimetic enzyme

Abstract

A novel catalytic spectrophotometric method for the determination of superoxide anion radical (O 2 −) and superoxide dismutase (SOD) activity is proposed. The method is based on the coupling reaction of 2,4-dichlorophenol (2,4-DCP) and 4-amino antipyrine in the presence of H 2O 2, catalyzed by a Schiff base metal complex included by β-cyclodextrin cross-linked polymer (β-CDP) as a mimetic enzyme. The contribution describes the design and synthesis of a novel Schiff base, salicylidene-2-amino-4-phenylthiazole (SAPTS) as well as a series of its metal complexes: M(II)–(SAPTS) 2 [M: Cu(II), Co(II), Zn(II), Ni(II)], among which Cu(II)–(SAPTS) 2 exhibits efficient horseradish peroxidase-like catalytic activity. Investigations of the optimum reaction conditions, the mechanism, and effects of coexisting substances are presented. The linear calibration range and the detect limit (3 σ) of the developed method for superoxide is from 0.0 to 1.0×10 −3 and 7.54×10 −7 M, respectively. The determinations of SOD activity in human/rat blood, garlic, onion and scallion serve as models for the proposed method. A comparison of the results with established classical analysis is satisfactory.