Monitoring 1,6-hexamethylene diisocyanate in air by chemosorption sampling. Scand j work environ health 9 (1983) 497-503. A sampling procedure for 1,6-hexamethylene diisocynate (HDI) in air is described. The diisocyanate is trapped on a chemosorption tube containing 9-(N-methylaminomethyl)anthracene adsorbed on Amberlite XAD-2. Recoveries in the laboratory experiments were 81-91%. The chemosorption technique was evaluated in the field by measurements at two different factories using HDI as a hardener in two-component paints for vehicle refinishing. Simultaneous sampling with a fritted-glass bubbler and by the chemosorption technique showed equal collection efficiencies for HDI when 3.5- to 22-1 air samples were used. For air samples exceeding 20 1 the collection efficiency of the fritted-glass bubbler decreased. Several additional peaks appeared in the chromatograms from the fritted-glass bubblers. Statistical treatment of the data showed that these peaks are closely related to the amount of HDI.