Fast, Accurate, and Point-of-Care Electrochemical Sensing Platform for Theobromine Determination in Food Samples Based on Boron-Doped Diamond Printed Electrode

Theobromine (3,7-dimethylxanthine; TB) is a naturally occurring alkaloid found in various food products, such as chocolate, making cocoa and chocolate products its primary dietary sources. TB levels are higher in cocoa beans, approximately 1.2–5 g/100 g, in dark chocolates, approximately 1 g/100 g, and in milk chocolates, 0.1–0.5 g/100 g. This work describes a determination of theobromine with a screen-printed sensor with chemically-deposited boron-doped diamond electrodes (BDD SPEs). The proposed method has LOD of 0.5128 μM and a LOQ of 1.5539 μM, with BDD SPEs in 0.5 M H 2 SO 4 , for theobromine. Linear concentration range was obtained from 1 to 60 μM. Determination of TB was performed in the real sample analysis-chocolates with two different percentages of cocoa, using BDD SPEs, and results were confirmed with HPLC analysis. Furthermore, the modified BDD SPEs demonstrate remarkable characteristics, including exceptional stability, consistent repeatability, and optimal readiness for real-world applications.