Folate determination in human health: UPLC–MS/MS is the emerging methodology of choice

This Perspective provides a brief description of the essential role that folates play in human health, together with an overview of the various analytical methods that have been used for quantitation of folates in human populations over the past few decades. Essentially, folate methodology has evolved from microbiological assay-based, to binding-based technology and, more recently, to separation-based methodology. Separation-based methods initially used traditional LC in conjunction with various detection techniques, with the most recent methods utilizing UPLC–MS/MS. Current UPLC methods offer exceptional speed, sensitivity and quantitation ability for the monoglutamate folate isoforms. It appears that the only limitation to properly quantifying all folates as polyglutamates, some 40–50 species, is the current lack of corresponding stable-isotope standards. Clearly, UPLC–MS/MS is emerging as the 'method of choice' for the determination of folates, whether in support of basic research, clinical investigations or population studies.