MS tools for a systematic approach in survey for carotenoids and their common metabolites

Metabolism of the carotenoids in humans is often reserved to bioconversion of provitamin A carotenoids in retinoids and oxidative/degradative products arising from enzymatic eccentric cleavage, yielding apo-carotenoids. Nevertheless, additional metabolic routes should be available, and some of the structures of those metabolites have only been anticipated. The identification of carotenoids and their metabolites is commonly performed by HPLC coupled to MS. The acquisition of MS data in different instrumental modes and hardware configurations allows the detailed structural description of the target compound. Indeed, the MS data of carotenoids and their metabolites available in literature could be collected in a database to automatically perform a screening of the theoretical MS data included in the database with the MS experimental values. This review describes the required fundamentals for a systematic pursuit of carotenoids and their metabolites. Highlights on the use of appropriate hyphenated HPLC-MS systems and the requirements for the identification are discussed, while the application of software tools to apply filtering rules and the implementation of post-processing workflow, which uses two orthogonal criteria for the identification from the mass spectra data, are described.