GAS-CHROMATOGRAPHIC DETERMINATION OF PRIMARY AND SECONDARY LOW-MOLECULAR-MASS ALIPHATIC-AMINES IN URINE USING DERIVATIZATION WITH ISOBUTYL CHLOROFORMATE

A simple routine method for the gas chromatographic determination of m ethylamine, dimethylamine, ethylamine and methylethylamine in urine is presented. The method is based on a two-phase derivatization procedur e with isobutyl chloroformate as reagent. The reaction is quantitative in 10 min. We found no artifact formation of either choline or trimet hylamine (dietary amine compounds) or of dimethylethylamine or triethy lamine (catalyst amines in the industrial setting). The chromatographi c behaviour of the amine carbamates was excellent. The recoveries of m ethylamine, dimethylamine, ethylamine and methylethylamine in spiked u rine samples were 82, 89, 100 and 96%, respectively, and the precision (the relative standard deviation) was 3.6, 1.8, 3.3 and 2.0%, respect ively. The method was linear for the studied amine carbamates up to 25 0 mg/l. The endogenous amine concentrations in urine samples from ten normal subjects were: methylamine, 0.9 mg/l (mean; range 0.3-1.5); dim ethylamine, 14.7 mg/l (mean; range 4.6-27.6); ethylamine, 0.8 mg/l (me an; range 0.2-2.3); methylethylamine, less than 0.02 mg/l.