[The biological monitoring of occupational exposure to anesthetic gas and vapors: the determination of nitrogen protoxide, halothane and isoflurane in the urine].

A gas-chromatographic method has been developed for measuring urinary nitrous oxide, halothane and isoflurane concentrations. A volume of head-space gases obtained from biological samples is analyzed by ECD-GC on a steel column (2 mm ID) serially packed with Porapak Q (1.2 m) and MS-5A (0.30 m), operated at 160 degrees C. The detection limit (ranging from 0.03 micrograms/l for halothane to 1 microgram/l for nitrous oxide), between-day precision (CV < 6%) and working linear range (up to 100 micrograms/l for halothane and 2000 micrograms/l for nitrous oxide) were determined. A two-year experience in biological monitoring of occupationally exposed surgical staff with the proposed method is reported and confounding factors are discussed. The method is easy to perform, free from interferences and suitable for use in routine analysis in toxicological laboratories.