A Co(II)–organic framework and peroxidase mimetic Hemin@metal–organic framework and its application in the colorimetric analysis of glucose

Abstract

A Co(II)‐organic framework (Co‐MOF), [Co3(3,5‐bimpy)2(5‐cpia)2(H2O)2], was constructed via the hydrothermal reaction of 3,5‐bis(1‐imidazoly)pyridine (3,5‐bimpy) and 5‐(2′‐carboxylphenoxy)isophthalic acid (5‐H3cpia). The Co‐MOF possessed a three‐dimensional (3D) porous architecture with the porosity of 22.4% per unit volume. The Co‐MOF@Hemin composite was further constructed via the encapsulation of Hemin into the Co‐MOF material. The constructed Co‐MOF@Hemin exhibited satisfactory peroxidase‐like activity through catalytic oxidation of the colorless peroxidase substrate 3,3,5,5‐tetramethylbenzidine (TMB) to a blue‐colored oxTMB in the presence of H2O2. Hence, the detection of H2O2 was achieved with a wide linear range from 0.005 to 0.5 mM (R2 = 0.992) and a low detection limit of 1.26 μM. More importantly, the peroxidase‐like Co‐MOF@Hemin was suitable for the sensitive and selective detection of glucose under the presence of glucose oxidase (GOx), which reduced O2 to H2O2. This analytical procedure for the detection of glucose had a linear range from 0.3 to 3 mM (R2 = 0.997), with a detection limit of 49 μM. The experimental results display the broad application prospects of the enzyme‐based MOFs in green and selective targets analyses.