Detection and Assay of Riboflavin (Vitamin B2) Utilizing UV/VIS Spectrophotometer and Citric Acid Buffer

Abstract

Aims: Riboflavin is a B vitamin that is required for a wide variety of cellular processes. The absorbance spectrum of riboflavin was determined at different pH utilizing several buffers. The buffer at pH demonstrating stable absorbance peaks with high numerical values of molar absorptivity is followed by accurate and sensitive assay of riboflavin by spectrophotometer. Study Design: The absorbance spectrum of riboflavin is determined in an aqueous buffer at various pH values. After identifying the absorbance peaks providing maximal molar absorptivity the assay of riboflavin in the identical buffer was undertaken. Place and Duration of Study: Department of Chemistry, Durham Science Center, University of Nebraska, Omaha Nebraska between August 2013 to December 2013. Methodology: An amount of riboflavin was dissolved in distilled water to make a stock solution of 0.0001100 molar concentrations. For determination of the absorbance spectrum one milliliter of the stock was diluted into various buffers of differing pH. The buffer having pH of 5.03 was selected for following assays with standard curve. Measurements of many aqueous solutions containing riboflavin were accomplished that included vitamin capsules/tablets and water vitamin mixtures. The data was evaluated meticulously utilizing several statistical numerical analysis methods. Results: The riboflavin is highly soluble in a citric acid buffer. The standard curve extended from 6.60E-07 M to 1.100E-04 M (167x spread in concentration). The equation of the line was y = 11882x (intercept at origin) with Pearson r correlation of 0.9998 (R2 = 0.9998). Concentration of riboflavin assayed can range from 0.000248 g per liter to 0.0414 g per liter. Accurate and reproducible results were obtained. Conclusion: The B vitamin riboflavin can be assayed by UV/VIS spectrophotometer at 440 nm in aqueous media and using citric acid buffer at pH 5.03. The assay for riboflavin in aqueous mixtures showed high levels of accuracy and sensitivity.