Novel Dual-Emission Carbonized Polymer Dot-Based Ratiometric Fluorescence Probe for the Sensitive Detection of Tertiary Butylhydroquinone

Tertiary butylhydroquinone (TBHQ), one of the most commonantioxidantsin many foods, has attracted widespread attention due to its potentialrisk to human health. In this work, an on-off-onratiometric fluorescent probe was prepared using dual-emission carbonizedpolymer dots (d-CPDs), which can be used to detect TBHQ in edibleoils. The ratiometric fluorescent sensing system consisted of bluefluorescent CPDs (b-CPDs) as the response signal and yellow fluorescentCPDs (y-CPDs) as the internal reference material. The blue fluorescenceof b-CPDs was gradually quenched with increasing Fe3+ ionconcentration, while the yellow fluorescence was essentially unaffected.Interestingly, TBHQ can restore the fluorescence intensity of b-CPDs.Meanwhile, the fluorescence mechanism of Fe3+ on b-CPDswas investigated by density functional theory, both after the additionof TBHQ, and CPDs were released and their fluorescence was restoreddue to the competitive reaction of TBHQ-Fe3+. Thus, thed-CPDs probe was able to detect Fe3+ accurately in an on-offmanner and thus TBHQ in an off-on manner. Atan optimal Fe3+ concentration, the ratiometric sensingsystem provided fine linearities for determining TBHQ in the rangefrom 0.2 to 2 mu M and an ingenious detection limit of 0.052 mu M.The CPDs ratiometric fluorescent probe designed in this work may havea broader application in the rapid, susceptive, and low-cost determinationof TBHQ in various foods.

Automated summary

In this study, a dual-emission carbonized polymer dot (d-CPDs) fluorescent probe was developed to detect tertiary butylhydroquinone (TBHQ) in edible oils. The probe utilized blue fluorescent CPDs (b-CPDs) as the response signal and yellow fluorescent CPDs (y-CPDs) as the internal reference material. It was found that the blue fluorescence of b-CPDs was quenched by increasing Fe3+ ion concentration, but could be restored by TBHQ.