Fluorometric/colorimetric dual-mode sensor based on silicon quantum dots for rapid and on-site detection of...

Tert-butyl hydroquinone (TBHQ) is a synthetic phenolic antioxidant commonly found in food. The overuse of TBHQ poses a potential toxicity to human health, which has attracted significant attention in food safety. In this study, we developed a dual-mode test platform strategy centered on silicon quantum dots (SiQDs) for fluorometric/colorimetric TBHQ detection. The SiQDs with Fe (III) as the fluorescence switch and co-enzyme, were synthesized and characterized, facilitating the catalysis of TBHQ to 2-tert-butyl-1,4-benzoquinone (TBBQ). There was a linear correlation with TBHQ concentration in the range of 5-200 μM, with a limit of detection (LOD) of 0.12 μM. Furthermore, with the assistance of 3,3',5,5'-tetramethylbenzidine (TMB) as a chromogenic substrate, the nanoprobes exhibited good colorimetric detection performance for TBHQ, with an LOD of 7 μM in the 15-500 μM range. Moreover, smartphone-integrated agarose gel strips were successfully developed for simple TBHQ detection with naked-eyes and the quantitative analysis with a LOD of 15 μM. The fabricated sensors successfully monitored TBHQ levels in spiked edible oil samples with recoveries in the range of 89.05-109.61 % and relative standard deviations (RSDs, %) less than 1.75 %, suggesting applicability for the detection of TBHQ in a complex food matrix.