PURIFICATION AND ANALYSIS OF DRUG RESIDUES IN URINE SAMPLES BY ONLINEIMMUNOAFFINITY CHROMATOGRAPHY HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY CONTINUOUS-FLOW FAST-ATOM-BOMBARDMENT MASS-SPECTROMETRY

An automatic system for the on-line extraction and analysis of diethyl stilbestrol in the urine of rats and calves is described. Extraction w as done by injecting samples directly into an immunoaffinity column co ntaining antidiethylstilbestrol antibodies bound to a Sepharose matrix , and analysis was done by on-line high-performance liquid chromatogra phy with ultraviolet and continuous-flow fast atom bombardment mass sp ectrometry detectors. The system, consisting of one injector, two swit ching valves, and three pumps, was operated under computer control and allowed to perform a complete analysis of a sample in 28 min. An accu rate quantitation by isotope dilution was also possible, by the use of deuterated diethylstilbestrol as internal standard. The sensitivity o f the method, using selected-ion monitoring of the molecular ion of di ethylstilbestrol, was 2 ng/mL, injecting 1 mL of urine sample. Results obtained from analyzing the urine of rats and calves treated with die thylstilbestrol are presented.