The identification of unusual bile acid metabolites by tandem mass spectrometry: Use of low-energy collision-induced dissociation to produce informative spectra

The use of collision-induced dissociation (CID) tandem mass spectrometry (M S/MS) has been shown to produce fragmentation that is useful for the struct ural analysis of bile acids and their conjugates, Low-energy CID using a tr iple quadrupole has been used to help characterise bile acid identity but t he majority of work has been conducted using high-energy CID on specialised instrumentation. This paper describes the use of low-energy CID as a rapid method for identification of urinary bile acids and presents some examples of its use in the diagnosis of liver disease in infants. These include the differential diagnosis of peroxisomal disorders, identification of compoun ds (e.g. 3 beta,7 alpha-dihydroxy-5-cholenoic acid 3-sulphate) indicative o f 3 beta-hydroxy-Delta(5)-C-27-steroid dehydrogenase/isomerase deficiency a nd the confirmation of the identity of an unusual bile acid series consisti ng of different conjugates of lithocholic acid. The use of lithium cationis ation and derivatisation with aminosulfonic acids for the analysis of uncon jugated and glycine-conjugated bile acids has also been evaluated. Copyrigh t (C) 1999 John Wiley & Sons, Ltd.