A new and efficient high-performance electrochemical glucose sensor based on a metallopolymer derived from a cobaltate (III) Schiff base complex

Through a simple and effective reaction of the cobalt (II) acetate tetrahydrate with a new ONO-tridentate Schiff base ligand (L1), which contains a thiophenyl group, a mono-anionic complex of formula: [{4-Th-C6H4-C(O)CH-C(CH3)=N-C6H4-2-O}(2)Co](-)[Bu4N](+) (C1) was isolated. Spectroscopic tools (H-1 and C-13 NMR, FT-IR) and the crystal structure revealed that C1 consists of a mononuclear six-coordinate anionic Co(III) center with a pseudo octahedral geometry, and one tetrabutylammonium counterion to satisfy the negative charge of the coordination entity [Co-III(L1)(2)](-). Electropolymerization of C1 produces a conductive metallopolymer deposit on fluorine doped tin oxide (FTO) electrodes, which acts as an efficient glucose sensor, showing a linear amperometric response for glucose within a concentration range of 1.97 x 10(-7) M to 3.88 x 10(-6) M (R-2 = 0.993), limit of detection (LOD) of 9.27 x 10(-7) M and limit of quantification (LOQ) of 9.24 x 10(-6) M. This electrochemical sensor, which exhibit excellent reproducibility in the manufacturing process, was stable in environmental conditions and showed good reproducibility of the measurements for two weeks. In addition, the metallopolymer deposit was characterized by electrochemical techniques (cyclic voltammetry) and SEM microscopy.

Automated summary

In this study, a mono-anionic complex C1 was synthesized by a reaction between cobalt (II) acetate tetrahydrate and a new ONO-tridentate Schiff base ligand containing a thiophenyl group. The resulting metallopolymer deposit from electropolymerization of C1 on FTO electrodes served as an efficient glucose sensor with a linear amperometric response and low limits of detection and quantification. The electrochemical sensor showed excellent reproducibility in manufacturing process, stability under environmental conditions, and consistent measurements over a two-week period.