A novel electrochemical sensor based on a nickel-metal organic framework for efficient electrocatalytic oxidation and rapid detection of lactate

Abstract

Lactate serves as a biomarker for a plethora of microbial contamination in cow milk. In this context, a novel nickel-metal organic framework (Ni-MOF) modified platinum electrode was fabricated for the effective and reliable detection of lactate in cow milk samples. The Ni-MOF of mean size 12 μm in length and 0.7 nm in width was synthesized by an inexpensive mild solution method. The Ni-MOF modified platinum, platinum wire and Ag/AgCl were employed as the working, counter and reference electrodes to design a potentiostatic three-electrode configuration device. The developed Ni-MOF modified platinum electrode exhibits good sensitivities (106.617 and 29.533 μA mM⁻¹) towards lactate over the wide linear ranges of 0.01–0.9 and 1–4 mM with a correlation coefficient of R² = 0.99, a detection limit of 5 μM, a repeatability of 0.57% RSD and a stability of 95.3% for 20 days. The nano-flower like morphology of Ni-MOF provides accessible sites for the electro-oxidation of lactate and thereby high sensitivity to lactate. Furthermore, the developed electrode remained free from potential interfering species and thus provides a promising tool for rapid detection of lactate in cow milk samples.