Spectrophotometric determination of Folic acid (B9) by oxidative Coupling Reaction with 4-nitro-aniline

Abstract

Development of an easy, inexpensive, fast and selective spectrophotometric method for the determination of Folic Acid  (FA) by its reaction with 4-nitro aniline reagent, with good sensitivity, as an oxidative coupling method in the presence of Potassium permanganate solution, and it was found that the concentrations that were agreement with Beer-Lambert’s law at the wavelength of 374 nm ranged between 1- 21 µg/ml of folic acid solution, and a deviation from Beer’s law occurs at a concentration higher than 21 µg/mL, gave a linear coefficient and correlation coefficient its value is 0.9994, 0.9996, respectively, While the value of the molar absorption coefficient  12138.5 L/mol.cm and Sandel's sensitivity  0.0363 gm/cm2  with  the limits of qualitative and quantitative detection 0.103 and 0.363 μg / ml-1, respectively. The proposed method was successfully applied for the determination of folic acid in its pharmaceutical preparations, from Erbil Company – Iraq. Trade name (folic acide).