A smartphone-assisted colorimetric sensor based on Fe1-xS nanozyme for detection of glucose and ascorbic-acid in soft drinks

Due to their distinct enzyme-like catalytic activity, iron-based nanomaterials have attracted considerable attention from researchers in the field of biomolecular detection. However, the current literature predominantly focuses on iron oxide nanozymes, with limited attention given to iron sulfide (FexSy) nanozymes. In this work, a glutathione-modified Fe1-xS nanoparticles (Fe1-xS NPs) with a diameter of 4–6 nm was synthesized in one-pot aqueous solution at room temperature. The resulting Fe1-xS NPs exhibited superior peroxidase-like (POD) activity compared to natural horseradish peroxidase, indicating their potential as a promising alternative for POD applications. A sensor utilizing the POD activity of Fe1-xS NPs was developed for detecting glucose and ascorbic-acid (AA) in soft drinks. The detection limits for glucose and AA were determined to be 37 and 5.3 μM, respectively, with broader linear ranges of 200–700 and 10–500 μM. Moreover, Fe1-xS NPs demonstrated exceptional selectivity and anti-interference properties in detecting glucose and AA in soft drinks. Furthermore, this study proposed a smartphone-assisted colorimetric sensor based on Fe1-xS nanozymes for rapid and specific detection of glucose and AA. This technique has the potential to be utilized in the future for convenient and efficient detection of glucose and AA.