Witte L, Nau H, Fuhrhop J H, Doenicke A, Grote B
J Chromatogr. 1977 Jul 1;143(4):329-34. doi: 10.1016/s0378-4347(00)80979-2.
A simple procedure for the quantitative analysis of trifluoroacetic acid (TFA) in urine and serum from patients narcotized with halothane is described. This involves addition of sodium hydroxide to the body fluid, evaporation of the aqueous phase and esterification of TFA in concentrated sulphuric acid with 2,2,2-trichloroethanol. The gaseous phases above the reaction mixture were then analyzed by gas chromatography with a nickel-63 electron-capture detector. The detection limit was 1 microgram of TFA per mililitre of body fluid (200 microgram of body fluid are analysed) and the relative standard deviation was +/-6%. Patients treated with ethrane, another commercial anaesthetic, did not produce any detectable TFA.
