A RAPID PROCEDURE FOR THE PURIFICATION OF BIOLOGICAL SAMPLES TO BE ANALYZED BY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY

One of the major problems in the analysis of drugs in biological fluids such as plasma by high performance liquid chromatography on reverse-phase columns is to obtain insoluble extracts in the mobile phase, depending on the method of sample preparation, plus the irreversible retention of apolar compounds on the chromatography column. The present report proposes a rapid procedure for the purification of samples obtained by liquid-liquid extraction using small volumes of n-hexane. The method is based on the differential partition of matrix components between the n-hexane phase and the mobile phase consisting of water and of another organic solvent such as methanol or acetonitrile.