Application of chitosan/ZnTiO₃ nanocomposite as an electrochemical sensor for vitamin D detection in dairy products

Abstract

Vitamin D deficiency is linked to osteoporosis, cardiovascular diseases, and immune dysfunction, making rapid detection crucial for clinical and nutritional management. In this work, a novel immunosensor for determining the presence of vitamin D3 (V-D3) is developed and validated utilizing an electrode modified with a bovine serum albumin and vitamin D3 antibody, which is made of zinc titanate (ZnTiO₃) and chitosan nanocomposites on a glassy carbon electrode. The immunosensor exhibited a wide linear range from 1 to 870 ng/mL and a low detection limit of 0.071 ng/mL with high sensitivity (0.1139 µA/ngmL⁻¹). The repeatability test indicated no change in more than 15 successive measurements, and the value of the relative standard deviation (RSD) of the reproducibility tests was obtained to be 3.52 %. The immunosensor showed high selectivity in response to V-D3 and low interference by common blood proteins and metabolites. Spiking materials gave recovery between 86.64 % and 93.50 %, RSD ≤ 4.81 %, which also demonstrated perfect agreement with immunosorbent enzyme-linked assay (ELISA) in real samples of human blood and dairy products. The measurement of vitamin D in food samples is important to monitor the amount of intake and the risk of deficiency, which associates with a variety of health problems. These results illustrate the potential of clinical diagnosis and food safety monitoring with the immunosensor.