A Reversed-Phase HPLC Fluorimetric Method for Simultaneous Determination of Homocysteine-Related Thiols in Different Body Fluids

Low molecular weight thiols (cysteine, cysteinylglycine, glutathione [GSH] and homocysteine) are important intermediates in different metabolic pathways. Glutathione has a relevant role as an antioxidant in detoxification of toxic compounds and xenobiotics, and homocysteine represents a risk factor for cardiovascular, neurological, and congenital diseases. Homocysteine and GSH are metabolically related in a pathway including cysteine and cysteinylglycine as intermediates. For these reasons, determination of homocysteine and related thiols is of great importance in the diagnosis of several diseases. The measurement of these sulphur compounds can be performed by using different methods, such as liquid or gas chromatography/mass spectrometry, high-performance liquid chromatography (HPLC), or capillary electrophoresis. This study describes an HPLC method coupled with fluorimetric detection for the simultaneous determination of cysteine, cysteinylglycine, GSH, and homocysteine in different biological fluids (blood, saliva, urine, and cerebrospinal fluid [CSF]). The comparison of the results obtained by other authors, as well as the method validation and the analytical costs, indicate that this HPLC method is particularly suitable for routine measurement of thiols in different body fluids.