Detection of trace ascorbic acid in urine by “inhibition” fluorescent sensor based on periodate and highly luminescent N, B co-doped carbon dots

Herein, we presented an ingenious method for the detection of trace ascorbic acid (AA) using fluorescent sensing system, which was composed of periodate (IO4−) and nitrogen-boron co-doped carbon dots (N, B-CDs). Highly photoluminescent carbon dots with a quantum yield of 84.5% were synthesized by a one-step hydrothermal method using citric acid, ethylenediamine and boric acid as raw materials. The fluorescence of N, B-CDs could be statically quenched by IO4−, and non-fluorescent complexes were formed on the surface of carbon dots at the same time. With the pre-addition of ascorbic acid, the process of fluorescence quenching by IO4− was inhibited due to the preferential redox reaction between AA and IO4−. Based on the principle mentioned above, we designed the “inhibition” fluorescent sensor that can easily realize the detection of AA, and an extremely low limit of detection of 0.035 nM with a linear interval of 0–1600 pM was obtained. In addition, the sensing system has been applied to the detection of AA in human urine and obtained satisfactory results. The developed “inhibition” fluorescent sensor with high sensitivity and selectivity, has shown great potential and application prospects in the field of biosensing.