SIMULTANEOUS DETERMINATION OF VITAMIN B COMPLEX (THIAMINE, RIBOFLAVIN, NIACIN, PYRIDOXINE AND FOLIC ACID) IN FOODS BY HPLC

摘要

A high performance liquid chromatographic assay has been developed for the simultaneous determination of five water soluble vitamins:thimine, riboflavin, niacin, pyridoxine and folic acid in cereal products and fresh vegetables. Food samples were hydrolyzed in 0.4 mol/L HCl, autoclaved at 120℃ 15 psi for 20 minutes, using a μ-Bondapak column （3.9×300mm, Waters Co.）, a mobile phase of methanol-water （30:70） （0.005 mol/L heptanesulfonic acid） and a flow rate of 1.0 ml/min gave the most satisfactory separation of the five water soluble vitamins. A double channel deteetion was used: four vitamins （B₅, folic acid, B₂, B₁） were detected hy UV spectrophotometry （254 nm） first, pyridoxine （B₆） was detected by fluoromelry （EX 290nm, EM 395 nm） afterwards. Detection limits were 2, 5, 5, 2and 5ng, linear ranges were 5-10ng, 5-50ng, 5-40ng, 5-50ng and 10-50ng for B₁, B₂, B₅, B₆ and folic acid respectively. Recoveries were 92-100%（B₅）, 51-52% （folio acid）, 103—105% （B₂）, 99—100% （B₆） and 91.3—102% （B₁） respectively. In comparison with a reference method and checking with food composition tables, very satisfactory results were obtained by this method.