Spectrophotometric Determination of Acidity Constants of Group B Vitamins in Different Ionic Strengths at 250.1

Journal of the Korean Chemical Society

S. Ghobadi¹  J. Ghasemi¹  M. Kubista¹  B. Abbasi¹ 

关键词: pKa Values;    Ionic Strength;    Vitamin B Group;    Acidity Constants;    DATAN;    Distribution Diagrams;    pKa Values;    Ionic Strength;   

DOI  :  

学科分类：化学（综合）

来源: Korean Chemical Society

【 摘 要 】

The apparent acid dissociation constants of four water-soluble vitamins, folic acid (vitamin B9 or B0), thiamine (vitamin B1), riboflavin (vitamin B2) and pyridoxal (vitamin B6) were determined spectrophotometrically in different ionic strengths at 25 ¡ÆC¡¾0.1. An accurate and sophisticated method based on chemometrical concepts was applied in order to determine acidity constants at different ionic strengths. For this purpose, spectral titration data were used. The spectra were recorded in the range 225-500 nm at different ionic strengths. The acidity constants of all vitamins at various ionic strengths were calculated by means of computer fitting of the pH-absorbance data with appropriate mass balance equations according to mono-, di- or triprotic acids. The computer program DATAN was used to extract the desired information from the spectral data. The outputs of the fitting processes were acidity constants, spectral profiles of pure forms, distribution diagrams, and other factor analysis data. The effect of ionic strength on the acidity constants is discussed.

【 授权许可】

Unknown