Solid-phase cation exchange extraction of basic drugs from the urine of racing greyhounds

The extraction of basic drugs from the urine of racing greyhounds has been carried out for many years using solvent extraction. This paper describes an extraction method that utilises a cation exchange column. Fourteen basic drugs were introduced onto the column in their ionised form, washed with organic and aqueous solvents and eluted with basic methanol. Three drugs, cyclizine, procaine and quinine were determined in authentic samples from racing greyhounds. A comparison of the solid-phase method with liquid-liquid extraction showed an increase in the efficiency of extraction and a reduction in both the time and cost incurred. The method requires a minimal volume of sample and solvent, little glassware and is easily automated.