Advances and challenges in neurochemical profiling of biological samples using mass spectrometry coupled with separation methods

Neurochemicals are mainly distributed in the central nervous system, and related to various neurological functions and disorders. Because neurochemicals are biosynthesized and metabolized through multiple pathways, it is difficult to understand the overall nervous system or to diagnose neurological disorders based on certain neurochemical levels. Therefore, to learn more about the nervous system and neurological disorders, metabolomics approaches should be used to profile the metabolic pathways of neurochemicals. To date, the neurochemical profiling has been pursued by various methods, especially including mass spectrometry (MS) coupled with conventional chromatographic techniques, which can sensitively and selectively determine numerous neurochemicals in biological samples. Nevertheless, the development of chromatographic MS-based analytical platforms to profile neurochemicals in biological samples has faced several challenges. This review was organized to help characterize neurochemicals using descriptions of the basic procedures (sample preparation and chromatographic MS detection). Moreover, we describe clinical applications and performance evaluation of these techniques.