Study of a Lanthanide Fluorescence System With a Coupled Reaction Based on Hemin Catalysis

Abstract

The oxidation reactions of three substrates, p-hydroxybenzoic acid (HBA), p-hydroxyphenylacetic acid, and p-hydroxyphenylpropionic acid, with H ₂ O ₂ catalysed by hemin were studied. It was significant that only the oxidation product of HBA, di-p,p′-hydroxybenzoic acid, forms a long-lived fluorescent complex with Tb ³⁺ . The three substrates themselves do not form fluorescent complexes with Tb ³⁺ although they have chemical structural similarities. Based on this, a novel lanthanide fluorescence system with a coupled reaction was developed. The possible reactive mechanism is discussed. HBA was concluded to be well suited to several types of application from hemin determination to bovine serum albumin labeling.