APPLICATION OF HIGH-PERFORMANCE LIQUID-CHROMATOGRAPHY CHEMICAL-REACTION INTERFACE MASS-SPECTROMETRY FOR THE ANALYSIS OF CONJUGATED METABOLITES - A DEMONSTRATION USING DEUTERATED ACETAMINOPHEN

The combination of a universal high-performance liquid chromatography/ mass spectrometry (HPLC/MS) interface (Ur) and the element and isotope -selective capabilities of the chemical reaction interface (CRI) has p otential as a comprehensive analysis system for drug conjugates. In th is work, we found equal sensitivity for model compounds as their sulfa te or glucuronide conjugates. We examined urine and bile samples from Syrian golden hamsters after dosing with (H-2(4))acetaminophen (D-4-AP AP), with particular emphasis on the rich range of conjugated metaboli tes that are known to be produced. Seventeen metabolites were quantifi ed from a single chromatogram of urine; 14 were conjugates. With a com bination of authentic standards, selective hydrolysis, and sulfur-sele ctive CRIMS detection, at least partial identification of most of thes e metabolites was accomplished. The glutathione conjugate of APAP appe ars the dominant meabolite in bile. The quantitative pattern of APAP m etabolism found here is consistent with literature values. It does app ear that this HPLC/UI/CRIMS combination has substantial ability to car ry out comprehensive metabolite determinations, especially for conjuga ted species.