Nitrogen-doped carbon dots derived from mangosteen peel for the detection of Cr2O72-and and vanillin

Nitrogen-doped biomass carbon dots (MP-NCDs) based on mangosteen peel were prepared by one-step hydro- thermal method. Transmission electron microscopy demonstrated that MP-NCDs were spherical and their particle size ranged from 2.6 to 5.0 nm. X-ray photoelectron spectroscopy indicated that they were composed of C, N, and O elements. Fourier transform infrared revealed that their surface was equipped with oxygen-containing and amino-containing groups. Bright blue light emission characteristics were demonstrated. They had high light stability in aqueous solution and salt solution. Furthermore, MP-NCDs could be utilized as a bifunctional fluorescent probe for detecting Cr 2 O 7 2- and vanillin through the fluorescence quenching method, which exhibited high selectivity, sensitivity, and anti-interference performance. The detection limits of vanillin and Cr 2 O 7 2- by MP-NCDs were determined to be 2.33 mu M and 4.6 mu M, respectively. A detailed analysis was conducted on the fluorescence quenching mechanism. The performance of the sensing system was tested in real samples using river water and infant formula as models.