Nanomaterial-based electrochemical sensing of selenium: Performance, challenges, and future directions

초록

Selenium (Se) is a trace element with a narrow window between essentiality and toxicity, where both deficiency and excess pose significant health risks. Conventional analytical techniques, such as ICP-MS and AAS, offer excellent sensitivity, while being hindered by high operational costs, infrastructure demands, and limited portability. In response, nanomaterials-based electrochemical sensing has emerged as a practical and costeffective alternative for Se detection. This review provides a comprehensive overview of recent developments in nanomaterial-based electrochemical sensors for selenium detection in the environment, food, and clinical samples. The nanomaterial-based transducers are advantageous to enhance the sensing performance by enlarging the electroactive surface area, facilitating selenium accumulation, and improving interfacial charge transfer. A rigorous evaluation of key performance metrics, including limit of detection (LOD), linear range, reproducibility, and reusability, is presented to benchmark current state-of-the-art technologies. Consequently, AuNP-, Au/ AuND-, silver-, and HPHM/graphite-based sensors are found to be the best. However, most sensors target Se(IV) through a preconcentration-reduction-deposition-stripping sequence. Se(VI) is rarely measured directly; instead, it is converted or detected enzymatically/indirectly. Moreover, a significant stride remains to be made to make these sensors affordable and point-of-care ready.

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