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

Abstract

This work presents a novel method for the sensitive and selective detection of atmospheric hydroxyl radicals (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 OH. The impregnated SA can trap atmospheric 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 OH radicals that have participated in the reaction. This method provided a linear correlation for 2,5-DHBA concentrations from 1.0 × 10−13 to 3.0 × 10−10 M with a detection limit of 2.09 × 10−14 M, which corresponds to an OH range from 1.0 × 105 to 3.0 × 108 molecules/cm3 with a detection limit of 2.1 × 104 molecules/cm3. This method has been used to measure the atmospheric OH levels in Yangzhou.