The use of ion chromatography for the determination of volatile inorganic acids in workplace air

Abstract

The presence of inorganic acids in the air poses a threat to the health of workers. Volatile inorganic acids, e.g., hydrochloric acid, hydrobromic acid and nitric acid, may cause respiratory, eye and skin irritation. The presented method uses ion chromatography to determine the concentrations of hydrochloric, hydrobromic and nitric acids in air samples. The method is based on the collection of airborne volatile acids on impregnated quartz fiber filter, extraction of acids with deionized water, and analysis by ion chromatography with conductivity suppression. The separation was performed on the Dionex IonPac™ AS22 (4 × 250 mm) column for trace anion analysis. The carbonate/bicarbonate eluent was maintained at an isocratic flow rate of 1.2 ml/min. The calibration standard solutions have been covering the range of 0.2-5 mg/l of chloride, bromide and nitrate. The specified chromatographic conditions enable selective measurement of chloride, bromide and nitrate anions. The obtained mass concentration of each anion, having factored in the sample dilution, the conversion factor (to convert anion concentration to acid) and the volume of the air sample, allows the calculation of acid concentrations in the analyzed air. This method makes it possible to determine the concentration of hydrochloric acid, hydrobromic acid and nitric acid in the workplace air within the concentration range corresponding to 0.1-2 times the exposure limit value in Poland. The method meets the criteria for the performance of procedures for the measurement of chemical agents, listed in PN-EN 482. This article discusses the problems of occupational safety and health, which are covered by health sciences and environmental engineering. Med Pr. 2022;73(4):337-47.