Optimized Electrochemical Sensor for Ochratoxin A Quantification in Coffee and Wheat Matrices

Sensitive and selective ochratoxin A (OTA) detection in challenging food matrices (wheat, coffee) is achieved using a cost-effective electrochemical method. The approach utilizes commercial carbon black-graphite screen-printed electrodes (SPE CB-G) enhanced via in situ modification with cetyltrimethylammonium bromide (CTAB). Adsorptive stripping differential pulse voltammetry (AdSDPV) parameters are rigorously optimized using central composite design (CCD), resulting in an optimal deposition time of 205 s and a CTAB concentration of 80 μmol L^-1. The method achieves a limit of detection (LOD) of 1.39 ng mL^-1 and a limit of quantification (LOQ) of 4.20 ng mL^-1 in 0.2 mol L^-1 phosphate buffer (pH 7.0) solution. In roasted and ground Arabica coffee (Coffea arabica), the method demonstrates a LOD of 2.70 ng mL^-1 and a LOQ of 8.20 ng mL^-1, with recovery rates ranging from 94.64 to 109.86%, compliant with key regulatory standards. The presence of CTAB minimizes the matrix effects and ensures reliable and reproducible results. This optimized SPE-based sensor offers a practical and efficient alternative to conventional methods for routine food safety monitoring.