Determination of N-methylmorpholine in air samples from a polyurethane foam factory. Comparison between two methods using gas chromatography and isotachophoresis for analysis.

The N-methylmorpholine levels in workroom air in a polyurethane foam factory were determined by two methods in which midget impinger flasks were used for sampling. The analyses were performed by gas chromatography and isotachophoresis. The values obtained by the gas chromatographic method were 19% higher than those of the isotachophoretic method. Determinations of the amine in samples generated in laboratory experiments showed no statistical difference between the two methods. The mean air concentrations of N-methylmorpholine in different work areas of the factory ranged from 7 to 22 mg/m3. Urine was collected from seven workers and analyzed for N-methylmorpholine by gas chromatography. The amine concentrations and the excretion rates increased considerably during the workday.