Charcoal Sampling and Gas Chromatographic Determination of N, N-dimethylformamide in Air Samples from a Polyurethane Plant

A charcoal sampling method and a gas Chromatographie determination of N, N-dimethylformamide in the air of a plant producing polyurethane lumps is described. The collection efficiency was checked by drawing standard N, N-dimethylformamide air mixtures through the sampling tube at 0.1 1/min and detecting the organic vapors spectrophotometrically at 215.4 nm. At 1,000 mg/m 3 , samplings could be carried out for 190 min with negligible N, N-dimethylformamide losses (lower than 1 %). The analysis of N, N-dimethylformamide was performed by gas chromatography on Porapack Q and Tenax GC after extraction with 2 ml of acetone/100 mg of charcoal, with a mean recovery of 90 (SD 2) %, in the range of 0.05— 0.5 mg of N, N-dimethylformamide/100 mg of charcoal. The relative standard deviation of the entire procedure was 3.5 %. Because of the good adsorbing efficiency of the characoal, short-term sampling could be carried out at a relatively high N, N-dimethylformamide concentration. Stationary and personal sampling resulted in mean values ranging between 1.26 and 1.60 mg/m 3 . The method is particularly suitable in instances where other pollutants are present, and therefore it can be used also for other work areas as well.