Methanesulfonic acid – Determination of methanesulfonic acid in workplace air using ion chromatography (IC)
Air Monitoring Method – Translation of the German version from 2023
Claudia Schuh1 (Method development)Dietmar Breuer2 (External verification)
Morten Blaskowitz2 (External verification)
Ralph Hebisch3 (Head of the working group “Air Analyses” of the Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area, Deutsche Forschungsgemeinschaft)
Thomas Helmut Brock4 (Head of the working group “Analytics”)
Andrea Hartwig5 (Chair of the Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area, Deutsche Forschungsgemeinschaft)
MAK Commission6
1 German Social Accident Insurance Institution for the foodstuffs industry and the catering trade, Dynamostraße 7–11, 68165 Mannheim, Germany
2 Institute for Occupational Safety and Health (IFA) of the German Social Accident Insurance (DGUV), , Alte Heerstraße 111, 53757 Sankt Augustin, Germany
3 Federal Institute for Occupational Safety and Health (BAuA), Friedrich-Henkel-Weg 1–25, 44149 Dortmund, Germany
4 German Social Accident Insurance, Institution for the raw materials and chemical industry, Prevention - Department of Hazardous Substances, Biological Agents and Analytical Chemistry, Kurfürsten-Anlage 62, 69115 Heidelberg, Germany
5 Institute of Applied Biosciences, Department of Food Chemistry and Toxicology, Karlsruhe Institute of Technology (KIT), Adenauerring 20a, Building 50.41, 76131 Karlsruhe, Germany
6 Permanent Senate Commission for the Investigation of Health Hazards of Chemical Compounds in the Work Area, Deutsche Forschungsgemeinschaft, Kennedyallee 40, 53175 Bonn, Germany
Abstract
The analytical method described here permits the determination of methanesulfonic acid [75-75-2] occurring as inhalable particles and vapour in workplace air. The concentration range covers one tenth up to twice the currently valid Occupational Exposure Limit Value (OELV) in Germany of 0.7 mg/m3 (inhalable fraction). The short-term exposure limit (STEL) with an excursion factor of 1 for the inhalable fraction and vapour can also be checked. Sampling is performed using a flow-regulated pump to draw a defined volume of air through a quartz fibre filter, which is alkaline-impregnated with sodium carbonate and inserted into a GSP sampling system. The volumetric flow rate is 10 l/min. Two hours or 15 minutes are suitable sampling periods. Alternatively, an intake cone suitable for a flow rate of 3.5 l/min can also be used for a sampling period of 2 hours. The methanesulfonic acid deposited on the filter is extracted with an aqueous sodium carbonate/sodium hydroxide solution and analysed by means of ion chromatography using a conductivity detector. Quantitative determination is based on multiple-point calibrations with external standards. For an air sample volume of 1200 litres, the relative limit of quantification (LOQ) is 0.021 mg/m3. At an LOQ of less than 0.17 mg/m3, the measurement of the STEL is also possible with an air sample volume of 150 litres. The recovery is 100% and the expanded uncertainty is 22% for a 2-hour sampling period and 35% for a 15-minute sampling period.
