A RAPID METHOD FOR DETECTING BARBITURATES IN SERUM USING EI-SIM

A simple and rapid method for analysis of barbiturates in serum has be en developed. In order to extract and clean barbiturates in serum, a s eparation column packed with Extrelut and Florisil was used, and the e luate was directly analyzed by means of electron impact selected ion m onitoring (EI-SIM). Selected ions used were base peak ions of 10 barbi tuartes, and the internal standard used was allobarbital or secobarbit al. The calibration curves were linear over the range 0.5-5 ng. Extrac tion of replicate serum samples containing 20 mu g/1.5 ml and 5 mu g/1 .5 ml resulted in a recovery of 87.2-105.2% and 81.6-104.6%, respectiv ely, with the exception of phenobarbital, which was 151.9% and 172.1%, respectively. Secobarbital was also analyzed in the serum of 13 patie nts who had been given secobarbital intravenously. In 3 out of 10 case s, secobarbital levels greater than 1 mu g/ml were detected more than 72 h after administration. This method seems to have possibilities for clinical use.