EXTRACTION OF LOCAL-ANESTHETICS FROM HUMAN BLOOD BY DIRECT IMMERSION SOLID-PHASE MICRO EXTRACTION (SPME)

Local anaesthetics have been shown to be extractable from human whole blood samples by direct immersion (DI)-solid phase micro extraction (S PME). After deproteinization with perchloric acid, the pH of the clear supernatants of human whole blood samples containing the drugs were a djusted to about 7 with 10 M NaOH in the presence of NaCl; a polydimet hylsiloxane-coated SPME fiber was then immersed directly into the samp le solution to allow adsorption of the drugs before capillary gas chro matography (GC) with flame ionization detection. The DI-SPME for 1-mL whole blood gave peaks for all the drugs; only a small amount of backg round noise appeared and this gave no problems in the detection of the drugs. Recoveries of the ten drugs from human whole blood was 0.74-19 .7 %. The calibration curves for seven drugs showed linearity in the r ange of 0.25-12 mu g mL(-1) whole blood, with detection limits of 54-1 58 ng mL(-1).