Development of laccase electrochemical biosensor for detection of Dephostatin using ZrO2/β-cyclodextrin/Polyaniline nanocomposite

Nitrosamines are mutagenic substances that threaten the health of living organisms, so their quick and accurate detection is very important. Dephostatin (Dph) as an aromatic N-nitrosamine can competitively inhibit the activity of protein-tyrosinase phosphatase. In this study, a novel nanostructured electrochemical biosensor based on Zirconia − β-Cyclodextrin − Polyaniline /Laccase (ZrO2-βCyD-PANI /Lac) was realized for the determination of Dph. At first, ZrO2-βCyD-PANI nanocomposite material was chemically synthesized and dropped on a screen-printed carbon electrode (SPCE). After that, Lac was immobilized on the nanocomposite electrode surface. The modified electrode surface was investigated using scanning electron microscopy (SEM), electrochemical impedance spectroscopy (EIS), and cyclic voltammetry (CV). The ZrO2-βCyD-PANI nanocomposite as a platform for Lac immobilization shows excellent electrode conductivity for amperometric biosensor. The composition of the nanocomposite, pH, and temperature were among the experimental parameters that were examined and modified to get the superior analytical performance of the biosensor. Amperometric studies displayed the fast response (optimum response in 15 s) of ZrO2-βCyD-PANI /Lac/SPCE biosensor toward Dph in a broad concentration range of 0.05 to 100 nM with a limit of detection (LOD) of 0.029 nM, limit of quantitation (LOQ) of 0.098 nM, and high sensitivity (234 μAcm-2µM). The proposed biosensor showed excellent selectivity, satisfactory stability, and suitable reproducibility (RSD = 2.5 %) and repeatability (RSD = 2.27 %) for Dph detection in malted drink and milk powder samples, and the results obtained from it do not show significant differences with the standard HPLC method.