Method for the determination of chlorinated hydrocarbons in workplace air using gas chromatography after thermal desorption

This analytical procedure is a validated measurement method for the determination of chlorinated hydrocarbons (CHCs) such as dichloromethane, tetrachloroethylene, 1,1,1‐trichloroethane and trichloroethylene and for monitoring their Occupational Exposure Limits (OELs) or MAK values in workplace air. Sampling is performed by drawing a defined volume of air through an adsorption tube filled with Chromosorb 106 using a flow‐regulated pump. The flow rate is set to 5 mL/min with a recommended air sample volume of 200 mL. The collected chlorinated hydrocarbons are thermally desorbed and analysed by means of gas chromatography fitted with two detectors, a flame ionisation detectors (FID) for quantification and a mass selective detector (MSD) for identification and quantification. The quantitative determination is based on calibration functions obtained by means of 10‐point calibrations. The limits of quantification (LOQs) are determined on the basis of aliquots from 1 to 10 mL of the calibration gases in the lower concentration range. The LOQs ranged from 0.85 to 4.3 mg/m3 based on air sample volumes of 200 mL. The expanded uncertainties ranged from 13 to 23% over the entire measuring range. Joint Publication of the Analytical Subcommittee of the Chemistry Board of Experts of the Expert Committee Raw Materials and Chemical Industry of the German Social Accident Insurance and the Working Group “Air Monitoring Methods” of the Permanent Senate Commission of the DFG for the Investigation of Health Hazards of Chemical Compounds in the Work Area.