▎ 摘　　要

The hydroxyl radical (OH) is one of the most important oxidizing species in air whose concentration indicates the air quality. In this work, an indirect method was developed to determine OH based on the electrochemical signal of 2,5-dihydroxybenzoic acid (2,5-DHBA), a specific reaction product of salicylic acid and OH. The molecular imprinting technique was introduced into this work to improve the selectivity and sensitivity of this method. 2,5-DHBA was imprinted on reduced graphene oxide (rGO) via a simple electrochemical method by using pyrrole as the functional monomer. rGO not only provides abundant active sites for 2,5-DHBA imprinting but also improves the conductivity and mass transportation and increases the accessibility of active sites for 2,5-DHBA recognition. The differential pulse voltammetry (DPV) signals of 2,5-DHBA were used to evaluate the performance of the molecularly imprinted polymer (MIP) based sensor. The linear range for the concentration of 2,5-DHBA was from 5.0 x 10(-8) to 4.5 x 10(-5) M and the detection limit was down to 2.74 x 10(-9) M. A linearity for OH concentration ranging from 8.4 x 10(6) to 7.5 x 10(9) molecules per cm(3) was obtained. The low detection limit for OH was down to 4.6 x 10(5) molecules per cm(3) when using this sensor. The atmospheric OH concentration in Yangzhou has been successfully detected by this method. This work extended the molecularly imprinted polymers to the indirect detection of OH in the atmosphere with a simplified sample collection and detection process and good sensitivity.