Edward W. Toepfer

Fluorometric determination of pyridoxamine by conversion to pyridoxal cyanide compound.

Abstract A fluorometric assay for pyridoxamine is described based on the fluorescence of pyridoxal cyanide compound obtained by transamination of pyridoxamine to pyridoxal which was then reacted with potassium cyanide. The reactions were reproducible from 0.001 to 1.00 μg/ml pyridoxamine. Fluorescence spectra of pyridoxamine and pyridoxal show little or no interference with fluorescence readings of pyridoxal cyanide compound at 358 and 435 mμ, activating and fluorescence wavelengths.

RECENT DEVELOPMENTS IN THE ANALYSIS FOR VITAMIN B6 IN FOODS.

Publisher Summary In foods and like materials, vitamin B 6 occurs naturally as pyridoxine, pyridoxal, and pyridoxamine, either free or combined with other substances such as phosphate. No one assay procedure has been satisfactory for all three forms; therefore, procedures for separating and determining them individually are important and essential developments for the vitamin B 6 assay. This chapter discusses four different procedures for separating and determining vitamin B 6 : microbiological procedures, chromatographic separation, comparative data, and fluorometric procedures. Microbiological procedures have been used successfully in the assay of foods and biological materials for vitamin B 6 content, but physical and chemical methods were satisfactory only with relatively concentrated and pure preparations. Chemical procedures were proposed for the determination of pyridoxine, pyridoxal, and pyridoxamine based on the fluorescence of the lactone of 4-pyridoxic acid. Several ion exchange resins were used, depending on circumstances, to separate pyridoxine or pyridoxal from the extracts or solutions.