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IMPROVED CHROMATOGRAPHIC SEPARATION AND FLUOROMETRIC DETERMINATION OF VITAMIN B 6 COMPOUNDS IN FOODS
Author(s) -
GREGORY J. F.,
KIRK J. R.
Publication year - 1977
Publication title -
journal of food science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.772
H-Index - 150
eISSN - 1750-3841
pISSN - 0022-1147
DOI - 10.1111/j.1365-2621.1977.tb12670.x
Subject(s) - chemistry , chromatography , reagent , extraction (chemistry) , fraction (chemistry) , organic chemistry
Several fluorometric procedures have been previously developed for the determination of vitamin B 6 compounds in foods. These have mainly been based on the separation of pyridoxal (PAL), pyridoxine (PIN), and pyridoxamine (PAM) by column chromatography on Dowex AG 50W‐X8, chemical conversion of PIN and PAM to PAL, and formation of the 4‐pyridoxic acid lactone fluorophore by reaction with KCN. These procedures were limited by a cumbersome chromatographic procedure utilizing boiling potassium acetate buffers, and interfering compounds in the PAL fraction often precluded accurate measurement. In this study, Maillard browning pigments resulting from the autoclave extraction procedure were shown to interfere by reacting with KCN to form highly fluorescent products. To alleviate the interference problem, an alternative ion exchange chromatographic method was developed which eliminated the KCN‐reactive browning pigments from the PAL fraction. After the ion exchange clean up steps, PAL was determined directly by reaction with KCN, whereas PIN and PAM were fist converted to PAL by reaction with MnO 2 and sodium glyoxylate, respectively. The effectiveness of the procedure was demonstrated on casein in the presence or absence of glucose, and on selected food samples.