Glucuronic Acid and Sulfate Conjugates of Target Analytes

11 GLUCURONIC ACID AND SULFATE CONJUGATES OF TARGET ANALYTES 

One of the major advantages of LC-ESI-MS(/MS) over GC-MS is the capability to analyze intact glucuronic add or sulfate conjugates of target compounds and/or their phase-I-metabolites. This is particularly useful, e.g., when sample preparation steps required to hydrolyze phase-H-metabolites are difficult to verify, when intact phase-II-metabolites are to determine, or when more than one conjugation site is present in a phase-I-metabolite and the position of the glucuronic add or sulfate moiety is to be located. 

There are several examples of analytes relevant for doping controls that were studied in terms of their phase-II-metabolism using ESI-MS (/MS) such as anabolic steroids, 2.5.28,123 128 narcotics, stimulants, ° etc. These studies outlined the fact that the CID behavior of the con- 

Thevis, M., and Schanzer, W. (2007) Current role of LC-MS(/MS) in doping control. Analytical and Bioanalytical Chemistry, 388,1351-1358. 

and Henion, J.D. (1997) Direct determination of anabolic steroid conjugates in human urine by combined high-performance liquid chromatography and tandem mass spectrometry. Journal of Chromatography B, 690,65-75. 

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