Measurement of chloral hydrate,trichloroethanol, trichloroacetic acid and monochloroacetic acid in the serum and the urine by gas chromatography

Summary A gas chromatographic method for the determination of trichloroethylene metabolites in the serum and the urine is described.The trichloroethanol glucuronide in the urine was hydrolyzed to trichloroethanol by -glucuronidase. After an extraction with ethyl ether, the extract was dried at 20C, then the residue was extracted with n-hexane and was injected into a gas Chromatograph.Trichloroacetic acid and monochloroacetic acid in the urine were extracted with ethyl ether. After evaporation of the ethyl ether, the acids were methylated with methanolic hydrogen chloride, by heating, and the residue was taken up in n-hexane and was injected into a gas chromatograph. The peak-areas on the gas chromatogram of the trichloroethylene, chloral hydrate and methyl esters of trichloroacetic acid and monochloroacetic acid were measured respectively, using a calibration curve prepared in the same conditions.Procedure for measuring trichloro-compounds in the serum was the same as for that in the urine, except that the ethyl ether extraction of trichloro-compounds was conducted after deproteinization.The serum concentration of trichloro-compounds in the rabbit, after administering trichloroethylene orally, reached the maximum in the following order: trichloroethylene and chloral hydrate > free trichloroethanol, trichloroethanol glucuronide and monochloroacetic acid > trichloroacetic acid. The urinary metabolites of trichloroethylene did so in the following order: free trichloroethanol and monochloroacetic acid > trichloroethanol glucuronide > trichloroacetic acid.Read before the 45th Annual Meeting of Japan Industrial Health Association, Tokyo, April 8, 1972.