This analytical method is a validated measurement procedure for the determination of benzene [71-43-2] in workplace air averaged over the sampling period after personal or stationary sampling. Sampling is performed by drawing a defined volume of air through a thermal desorption tube filled with Carbopack B/Carbopack X using a suitable flow-regulated pump. Before sampling a toluene-D8 standard solution is applied to the sieve of each sample carrier. For the following sampling the flow rate is set to 0.33 l/min whereby an air sample volume of 2 l must not be exceeded. The samples must be analysed within 28 days after loading with internal standard. After thermal desorption at 280 °C the sample is analysed by means of GC with a mass spectrometric detector (MSD). The relative limit of quantification (LOQ) is 4 μg/m³ benzene for an air sample volume of 2 l. The mean recovery was 98% for an evaluation with MSD and the expanded uncertainty for benzene was approx. 25%.