Accurate voltammetric analysis of As(III) in cooked rice: A true reflection of actual human intake

Rice is one of the significant sources through which the human body absorbs arsenic(As) from the environment over extended periods in Asia, in addition to drinking water. In addition, owing to its distinct biological characteristics, rice has a notable capacity to absorb As from contaminated soil and water. Current detection methods often necessitate strong acid and high-temperature pretreatment of rice, which may lead to the oxidation of As(III) to As(V), thereby failing to accurately represent the actual intake of As(III) by humans. In this study, we employed a commonly used cooking method in daily life and directly analyzed rice soup via electrochemical techniques to most accurately reflect the actual intake of As(III) by humans. We developed a sensor based on P doped Fe-Co nanobox modified glassy carbon electrodes for precise and highly sensitive detection of As(III) in rice. This sensor demonstrated a sensitivity of 2.39 µA/ppb and achieved a detection limit as low as 0.06 ppb. Furthermore, it exhibited excellent stability and reproducibility. Additionally, through X-ray photoelectron spectroscopy (XPS) and X-ray absorption fine structure (XAFS) studies, we have demonstrated that electrons are transferred from Fe/Co sites to As(III) via the "electron bridge" formed by P atoms, enabling highly sensitive detection of As(III) in rice. Our findings present a novel approach for the development of a sensor at the accurate electrochemical detection of heavy metal ions in agricultural products and hold significant potential for future applications in engineering detection.