HPLC-FLD determination of folate vitamers and precursors in selected plant-derived foods

Folate are essential B-group vitamins involved in one-carbon metabolism and human health. Accurate determination of individual folate vitamers together with selected biosynthetic precursors remains analytically challenging because of their structural diversity, low endogenous concentrations, and distinct physicochemical properties. A sensitive and practical HPLC–FLD method was developed for the determination of individual folate vitamers together with selected biosynthetic precursors, and subsequently applied to selected plant-derived foods. The target analytes included dihydrofolate (DHF), tetrahydrofolate (THF), 5-methyltetrahydrofolate (5-MTHF), 5-formyltetrahydrofolate (5-FTHF), 10-formylfolic acid (10-FFA), folic acid (FA), p-aminobenzoic acid (p-ABA), and 7,8-dihydroneopterin (DHN). The method exhibited good linearity (R² > 0.994), satisfactory recoveries (73.01–100.80%), acceptable precision (RSD < 9%), and limits of detection reaching the “pmol” level for several analytes. The developed method was applied to selected plant-derived food samples, including cereals, soybeans, and vegetables, demonstrating its potential for characterizing differences in folate vitamer and precursor composition among the investigated food samples. Owing to its economical instrumentation, relatively simple sample pretreatment, and ability to quantify both folate vitamers and biosynthetic precursors, the proposed method provides a practical analytical tool for folate profiling in selected plant-derived foods, although further validation across additional food matrices would be required to establish broader applicability.