Estimation of methylglyoxal in cow milk – an accurate electrochemical response time based approach

Abstract

Cow milk contains carbohydrates that are prone to produce methylglyoxal (MG) which plays a major role in chronic complications of diabetes. In this context, an electrochemical biosensor based on a glyoxalase 1 (GLO 1) modified platinum electrode (Pt) with a ceria nano-interface (CeO₂) was developed. The fabricated Pt/CeO₂/GLO 1/chitosan nano-bioelectrode reduced MG and hemithioacetal at −0.771 and −0.558 V respectively in the presence of glutathione (GSH). Michaelis–Menten and Hill models were employed for the estimation of the response time. The accuracy of these models was validated by calculating the relative prediction error. The modified Hill model showed the best results in validation. The sensitivity of the Pt/CeO₂/GLO 1/chitosan nano-bioelectrode at −0.771 V was 2.868 μA μM⁻¹ over a linear range between 5 and 50 μM, with a detection limit of 2.14 nM, a quantification limit of 7.12 nM and a response time of less than 39 s. The fabricated electrode was demonstrated to be highly reproducible with a relative standard deviation of 1.02% over 10 successive amperometric calibrations. It also showed good recovery (99.21–101.72%), thus providing a promising tool for the analysis of MG in cow milk.