DETERMINATION OF TRAMADOL IN HUMAN PLASMA BY CAPILLARY GAS-CHROMATOGRAPHY MASS-SPECTROMETRY USING SOLID-PHASE EXTRACTION

An analytical method using solid-phase extraction, capillary gas chrom atography and mass selective detection in the electron-impact ionizati on (EI) mode was developed for the determination of tramadol thylamino )methyl]-1-(3-methoxyphenyl)cyclohexanol) in human plasma The advantag es of this method are the high sensitivity and selectivity and the lin earity over the concentration range 2-500 ng/ml. Quantification was ma de using nefopam as an internal standard, and the detection limit was found to be 1 ng/ml. The standard deviations of the intra-day precisio n test ranged from 4.5 to 6.0% with respect to the concentration. Accu racy ranged from 1.0 to 4.0% (inter-day). The method was used for the determination of tramadol in a bioequivalence study.