EVALUATION OF A SOLID-PHASE EXTRACTION PROCEDURE FOR THE SIMULTANEOUSDETERMINATION OF MORPHINE, 6-MONOACETYLMORPHINE, CODEINE AND DIHYDROCODEINE IN PLASMA AND WHOLE-BLOOD BY GC MS/

Different procedures of solid-phase extraction were re-examined and a new solid-phase extraction procedure was developed using gas chromatog raphy-mass spectrometry for the simultaneous detection and quantitatio n of morphine, 6-monoacetylmorphine, codeine and dihydrocodeine in pla sma and whole blood. The effects of differ ent types of sorbent and bu ffer solutions on the recoveries and purity of the extracts were also studied. Some preparation techniques on whole blood samples were also investigated. The method developed using Chromabond C18 (100) with spi ked plasma samples had good recoveries for all opiates of interest: mo rphine 93.1% +/- 7.4%, 6-monoacetylmorphine 68.0% +/- 6.7%, codeine 77 .0% +/- 8.3% and dihydrocodeine 67.9% +/- 8.4%. The detection limit of all compounds was less than 5 mu g/L. The blank plasma showed no inte rfering peaks in the GC/MS-analysis.