A design strategy of ratiometric probe based on dual-colored carbon dots for phosphate detection

Establishment of a rapid, sensitive, and selective quantitative assay of food additives was of great significance in food safety evaluation. In this study, a novel ratiomentric probe (B/Y-CDs) based on dual-colored carbon dots was developed to detect phosphates (Pi) in frozen seafoods. With the aid of the strong coordination ability of Tb3+ and electrostatic attraction, the nanoprobe (B/Y-CDs) was constructed composed of yellow emissive terbium-doped carbon dots (Y-CDs) and the blue emissive carbon dots (B-CDs). Consequently, the blue fluorescence signal was significantly quenched based on Förster resonance energy transfer. Upon the addition of Pi, the stronger coordination capacity with Tb3+ would make the Y-CDs prefer to combine with Pi, causing the desorption of B/Y-CDs, thus recovering the blue fluorescence. Meanwhile, Y-CDs fluorescence remains stable, presenting the ratiometric detection of Pi. The analytical potential of the probe was evaluated and a good linear range from 0.5 to 12 μM was achieved. The whole analysis process could be accomplished within 15 min. In brief, this study offered a new design strategy of ratiometric probe for rapidly and sensitively detecting Pi in seafoods, which demonstrated potential application value in food safety evaluation.