RESUMO
The performance of a benchtop GC-ion trap MS-MS instrument, the Varian Saturn 4D, was evaluated for the analysis of a model drug, tebufelone, in plasma. The sample preparation scheme was designed to provide a highly complex extract with matrix-derived interferences eluting near and at the retention time of tebufelone and its stable-isotope-labeled analog. The performance of the ion trap in the selected-reaction-monitoring mode was evaluated and also compared with results obtained on a benchtop GC-MS linear quadrupole instrument operated in the selected-ion-monitoring mode. The ion trap, operated in the selected-reaction-monitoring mode, was found to provide a higher degree of selectivity for the analysis of tebufelone. The increased selectivity obtained on the ion trap operated in the selected-reaction-monitoring mode resulted in superior accuracy and precision, as well as a lower limit of quantitation relative to that obtained by the GC-MS analysis. A linear standard curve was obtained over three orders of magnitude and the limit of quantitation for tebufelone in plasma was 100 pg/ml using the GC-ion trap MS-MS instrument.
Assuntos
Alcinos/sangue , Anti-Inflamatórios não Esteroides/sangue , Cromatografia Gasosa-Espectrometria de Massas/instrumentação , Fenóis/sangue , Animais , Isótopos de Carbono , Estudos de Avaliação como Assunto , Indicadores e Reagentes , Isótopos de Oxigênio , Coelhos , Padrões de ReferênciaRESUMO
An extraction and concentration procedure using a unique solid-phase extraction tube was developed for the analysis of 11-nor-delta 9-tetrahydrocannabinol-9-carboxylic acid in urine. Absolute and relative recoveries of the drug metabolite were found to be greater than 85% and 92%, respectively. The extraction procedure allows quantitation of the drug metabolite by GC/MS, HPLC with UV detection, or GC with flame ionization detection. The extraction procedure was verified with urine samples obtained from marijuana users as well as spiked urine samples.