Native Fluorescence Determination of Pyridoxine Hydrochloride (Vitamin B6) in Pharmaceutical Preparations After Sorption on Sephadex SP C‐25

Abstract

A simple, batch mode, solid phase spectrofluorimetric procedure has been developed for the determination of pyridoxine hydrochloride (PY) (vitamin B6). The method is based on the measurement of the native fluorescence of the analyte at 395 nm (λexc = 295 nm) sorbed on Sephadex SP C‐25 beads. The cation‐exchange gel, previously equilibrated with the sample solution, is packed in a 1‐mm quartz cell in which the measurements are performed (diffuse transmitted fluorescence). The method responds linearly in the measuring range of 50–500, 10–100 and 5–40 μg·l− 1 with detection limits of 9.5, 2.3 and 0.60 μg·l− 1 for 10, 25 and 50 ml of sample volume, respectively. The relative standard deviation (n = 10) for the determination of 100 (10 ml), 60 (25 ml) and 30 μg·l− 1 (25 ml) of PY is 1.3%, 2.2% and 3.7%, respectively. The method, which shows increasing sensitivity as the sample volume increases, was satisfactorily applied to the determination of vitamin B6 in pharmaceutical preparations using the procedure for 10 ml of sample.