Design and fabrication of a preconcentration-free Mg-doped hydroxyapatite based electrochemical sensor for simultaneous determination of cadmium, lead, and mercury in seafood and plant-derived foods.

Abstract

Heavy metal contamination in certain food remains a major public health concern due to the persistence, bioaccumulation, and toxicity of cadmium, lead, and mercury. In this study, we report the design and fabrication of a preconcentration-free electrochemical sensor based on magnesium-doped hydroxyapatite (Mg-HAP) nanoparticles for the simultaneous determination of Cd2+, Pb2+, and Hg2+ in food matrices using a non-stripping voltammetric approach. Mg-doped HAP ((Ca9Mg)(PO4)6(OH)2) nanoparticles were synthesized via microwave irradiation and characterized using powder XRD, XPS, and HRTEM. The Mg-HAP modified glassy carbon electrode exhibited wide linear ranges of 1-1770 μM (Cd2+), 1-995 μM (Pb2+), and 0.25-995 μM (Hg2+), with corresponding lowest detection limits of 0.874 μM, 0.132 μM, and 0.257 μM, respectively. The fabricated sensor demonstrated good selectivity along with satisfactory repeatability and stability. The sensor was validated in seafood (trevally, mullet and crab) and plant-derived foods (turmeric, mushrooms, peanuts), confirming its suitability for food safety monitoring.