SUBCRITICAL FLUID EXTRACTION OF MORPHINIC ALKALOIDS IN URINE AND OTHER LIQUID MATRICES AFTER ADSORPTION ON SOLID SUPPORTS

Supercritical fluid extraction (SFE) of liquid matrices is difficult a nd requires special instrumentation. An alternative is to load the liq uid on a solid support prior to extraction. This procedure yields high er selectivity and can be used as a clean-up step when very complex li quid matrices, such as urine, are to be analyzed. This paper demonstra tes the use of various solid supports in order to extract morphinic al kaloids with subcritical fluids (CO2 + polar modifier). Optimization o f the procedure with regard to loading conditions, SFE parameters such as pressure, extraction time, flow rate and eluent composition, was c arried out with morphinic alkaloids in aqueous solution. As a real-lif e application, SFE of opiates in urine were tested with two silica bon ded phase supports (C18 (polygosil 60-4063, from Macherey-Nagel) and B ond Elut Certify from Analytichem International). Recovery, variation coefficients and linearity are described for each procedure. Bond Elut Certify silica was chosen as the best solid support and SFE is compar ed with conventional solid phase extraction.