This standard specifies the procedure to be followed and the equipment necessary for the determination in the air of workplaces of the concentration of any of the following compounds: n-hexane toluene or its mixtures, by diffusion capture in passive bed samplers activated carbon adsorbent and analysis by gas chromatography. The analysis method has been validated for air samples containing the mixture of n-hexane and toluene in the following concentration ranges (see section 11.1): 27 mg/m3 to 626 mg/m3 (approximately 7 ml/m3 to 173 ml /m3) of n-hexane 29 mg/m3 to 660 mg/m3 (approximately 7 ml/m3 to 176 ml/m3) of toluene However, this analysis procedure may also be useful in concentration ranges greater than those previous. In any case, the upper limit depends on the adsorption capacity of the sampler and the lower limit of the useful range depends on a series of factors such as: noise level of the detector, blanks of the sample and reagents, desorption efficiency and interferences in chromatographic analysis. The result obtained with this procedure is an integrated average value of the concentration throughout the sampling period. It should not be used to measure instantaneous concentrations or concentration fluctuations over short periods of time. Any organic compound that has the same or close retention time as the analytes of interest is considered interference. These interferences can be minimized by selecting the appropriate columns and chromatographic conditions.