IMPROVED SUPERCRITICAL-FLUID EXTRACTION OF SULFONAMIDES

Different ways used for enhancing the yield of sulphonamides leached f rom solid supports are reported. Supercritical CO2 and methanol-modifi ed CO2 were used as extractants of the target analytes and the impregn ation of the solid sample with buffer, derivatization of the analytes and ion-pair formation were assessed. Only the sulphonamide/tetramethy l-ammonium ion-pairs are quantitatively extracted from the solid suppo rts using pure supercritical CO2, while the other modifications and th e presence of a cosolvent lead to recoveries lower than 30 % for most of the analytes. Individual separation/quantitation of the analytes wa s performed off-line using a liquid chromatograph.