The Analysis of B-1 Dye (1,P- Nitrophenylazo 2, Naphthylamine) by Ultraviolet-Visible Spectroscopy and Thin Layer Chromatography

摘要

The objective of this work was to study the analytical chemistry of B-1 dye in the areas of process control and dye purity. B-1 dye (p-nitrophenylazo, 2-naphthylamine) exhibits a typical electronic transition in the visible portion of the spectrum. The wavelength of this transition is a function of the hydrogen bonding ability of the dye to the solvent and the polarity of the solvent. A second electronic transition for this dye occurs in the near ultraviolet portion of the spectrum and may be ascribed to the p-nitrophenyl chromophore. The ratio of absorbance of these electronic transitions, (the absorbance index) is used as a criterion of dye purity. Deviations from this ratio are shown to be related to impurities or adulterants of the B-1 dye. The newly investigated Spectral Discrimination Technique is described and found to be insensitive to impurities having similar electronic transitions to that of B-1 dye. This technique appears to have little or no value in determining B-1 dye purity.