Salicylic acid impregnated activated carbon fiber paper: An effective platform for the simple and sensitive detection of hydroxyl radicals in the atmosphere

This work presents a novel method for the sensitive and selective detection of atmospheric hydroxyl radicals (center dot OH). After activation by a hydrothermal method in the presence of sodium citrate, carbon fiber paper (CFP) with good conductivity and hydrophilicity was impregnated with salicylic acid (SA) and used as a detector to monitor center dot OH. The impregnated SA can trap atmospheric center dot OH, producing 2,5-dihydroxybenzoic acid (2,5-DHBA), an electroactive species. The concentration of 2,5-DHBA was quantified using a simple electrochemical method to estimate the number of center dot OH radicals that have participated in the reaction. This method provided a linear correlation for 2,5-DHBA concentrations from 1.0 x 10(-13) to 3.0 x 10(-10)M with a detection limit of 2.09 x 10(-14)M, which corresponds to an center dot OH range from 1.0 x 10(5) to 3.0 x 10(8) molecules/cm(3) with a detection limit of 2.1 x 10(4) molecules/cm(3). This method has been used to measure the atmospheric center dot OH levels in Yangzhou.