SIMPLE ANALYSIS OF LOCAL-ANESTHETICS IN HUMAN BLOOD USING HEADSPACE SOLID-PHASE MICROEXTRACTION AND GAS-CHROMATOGRAPHY MASS-SPECTROMETRY ELECTRON-IMPACT IONIZATION SELECTED-ION MONITORING

A simple method for analysis of five local anaesthetics in blood was d eveloped using headspace solid-phase microextraction (HS-SPME) and gas chromatography-mass spectrometry-electron impact ionization selected ion monitoring (GC-MS-EI-SLM). Deuterated lidocaine (d(10)-lidocaine) was synthesized and used as a desirable internal standard (I.S.). A vi al containing a blood sample, 5 M sodium hydroxide and d(10)-lidocaine (LS.) was heated at 120 degrees C. The extraction fiber of the SPME s ystem was exposed for 45 min in the headspace of the vial. The compoun ds adsorbed on the fiber were desorbed by exposing the fiber in the in jection port of a GC-MS system. The calibration curves showed linearit y in the range of 0.1-20 mu g/g for lidocaine and mepivacaine, 0.5-20 mu g/g for bupivacaine and 1-20 mu g/g for prilocaine in blood. No int erfering substances were found, and the time for analysis was 65 min f or one sample. In addition, this proposed method was applied to a medi co-legal case where the cause of death was suspected to be acute local anaesthetics poisoning. Mepivacaine was detected in the left and righ t heart blood samples of the victim at concentrations of 18.6 and 15.8 mu g/g, respectively. (C) 1998 Elsevier Science B.V. All rights reser ved.