Improvement in the detection levels of bile acids, bile salts and aminoacids in the analysis by negative FAB-MS-MS

Bile acids, bile salts and aminoacids are important tracers of different ne wborn pathologies. Their detection and quantification by simple and secure methods are very important, specially if they can be carried out on the ori ginal biological fluid, avoiding previous isolation. In this sense, tandem Mass spectrometry is the method of choice. In order to improve the level of detection of these type of compounds when using negative FAB-MS-MS we trie d different concentrations of each of them in four different matrixes: trie thanolamine, glycerol, glycerol + NH4OH [7:2] and glycerol + NH4OH [2:7]. T he results allowed the construction of the sensitivity curves and the calcu lation of the respective detection limits (LOD and LOQ) for each of the sam ples in each of the different matrixes. The use of glycerol + NH4OH [7:2] i mproved greatly the detection level for all of them and resulted in a simpl e and effective option for the proposed study.