[Analysis of meperidine and its metabolites in urine of an addict by GC/FID and GC/MS].

Analytical methods of GC/FID and GC/MS for identification and determination of meperidine, an analgesic drug, and its metabolites were established. The determination of meperidine spiked in urine was shown to have a good linear relationship in the range of 0.1-8.0 micrograms/ml urine (Y = 0.4995X + 0.1201, r = 0.9996). The detection limit was 20 ng/ml urine. With the developed methods, meperidine and its metabolites in urine collected from a meperidine addict were identified and determined. Meperidine, normeperidine, meperidinic acid in free and conjugate forms, normeperidine acid in free and conjugate forms, and acetyl-normeperidine were detected. Among these metabolites, acetyl-normeperidine was reported for the first time.