Monitoring forN,N-Dimethylformamide andN,N-Dimethylacetamide with a Diffusive Sampler Using Distilled Water as an Absorbent

To obtain an appropriate sampling method for evaluating individual workers' exposure concentrations to chemicals highly soluble in water, the suitability of LiPS (liquid passive sampler) as diffusive sampler was examined. Although adsorbed chemical substances with activated carbon felt being used as the adsorbent must be desorbed in such samplers, this process can be omitted by using liquid as the absorbent. This kind of simplification can be utilized for water-soluble solvents such as N,N-dimethylformamide (DMF) and N,N-dimethylacetamide (DMAC). In laboratory experiments DMF and DMAC levels determined by this method were sufficiently correlated with exposure concentrations, exposure duration, and cumulative exposure levels. The sampling rates for DMF and DMAC obtained from these results were 0.50 and 0.43 mL/min, respectively, and the theoretical sampling rate for DMF obtained using Fick's diffusion formula was consistent with the experimental value. The effects of relative humidity, wind velocity, and temperature on the measured values were negligible within the range expected in a practical industrial environment. In a field survey the exposure concentrations for 38 workers handling DMF in the process of manufacturing spandex fiber and polyurethane gloves were determined both by this method and by the National Institute of Occupational Safety and Health (NIOSH) method, in which silica gel tubes are used. The DMF concentrations detected by the two methods were comparable (Y = 0.912X, correlation coefficient: 0.932). This LiPS method proved to be useful in determining the concentrations of DMF and DMAC to which workers were exposed.