A chemically and electrochemically stable, redox-active and highly sensitive metal azolate framework for non-enzymatic electrochemical detection of glucose

Herein, we demonstrated the development of a non-enzymatic glucose sensor based on a metal azolate framework (MAF-4-Co-II or Co(mim)(2), mim = 2-methylimidazole)-modified glassy carbon electrode (GCE). The as synthesized MAF-4-Co-II exhibited high crystallinity, purity, and chemical and electrochemical stability, which was characterized by various analytical methods. The MAF-4-Co-II exhibited good redox activity in the alkaline medium due to the formation of MAF-4-Co-II/MAF-4-Co-III redox pair, which concurrently induced the non-enzymatic oxidation of glucose to gluconolactone. The MAF-4-Co-II/GCE sensor exhibited wide dynamic ranges in the concentration range from 2 to 50 mu M and 100 to 1800 mu M with high sensitivity (ca. 990.90 and 30.95 mu A/cm(2)/mM, respectively), low detection limit (ca. 0.60 mu M), reproducibility, and selectivity. The practical applicability of this sensor was evaluated using diluted human serum samples, which revealed excellent recoveries of glucose. Thus, MAF-4-Co-II can be used as a promising electrocatalyst for non-enzymatic detection of glucose with high stability.