Graphene quantum dots as nanoprobes for fluorescent detection of propofol in emulsions

We report a new fluorescent detection method for propofol based on graphene quantum dots (GQDs). Citric acid (CA) was selected as the carbon precursor, and fluorescent GQDs were prepared by carbonizing CA. The product, which efficiently quenched the fluorescence of GQDs, could be obtained through the oxidation of propofol in the presence of horseradish peroxidase and hydrogen peroxide. The fluorescence intensity ratio of GQDs (F/F ₀) was positively correlated with the concentration of propofol, which ranged within 5.34-89.07 mg l^-1, the limit of detection was 0.5 mg l^-1 and the limit of quantity was 5.34 mg l^-1. The developed fluorescence method reported in the present study is simple, sensitive, reproducible, and can serve in determining propofol contents in emulsions.