Smartphone-assisted fluorescence sensor based on iron-doped carbon dots for rapid detection of tert-butyl hydroquinone in edible oils.

Given the health risks of tert-butylhydroquinone (TBHQ), rapid, portable, selective, and sensitive quantification in edible oils is critical. With this in mind, a fluorescent "on-off-on" probe was developed based on rationally designed iron-doped carbon dots (CDs). The blue fluorescence of the CDs is quenched by Fe3+ ions and recovered by TBHQ, enabling Fe3+ detection in an "on-off" mode and TBHQ detection in an "off-on" mode. The probe exhibited excellent linearity for TBHQ over the range of 0.2-1.8 μM, with a low detection limit of 0.067 μM. Moreover, a smartphone-assisted sensor was constructed to enable portable TBHQ quantification in edible oils samples. This CD-based probe shows strong promise for the rapid, sensitive, and cost-effective monitoring of hazardous substances.