SPECTROPHOTOMETRIC ESTIMATION OF FOLIC ACID (VITAMIN B9) USING AN OXIDATIVE COUPLING METHOD WITH (E)-N’-(1-(2NITROPHENYL)ETHYLIDENE)QUINOLINE-6-CARBOHYDRAZIDE(M4)

Abstract: A simple, cost-effective, and highly sensitive spectrophotometric method was developed for the determination of folic acid (vitamin B9). The method is based on an oxidative coupling reaction with a synthetic reagent, (E)-N’-(1-(2-nitrophenyl)ethylidene)quinoline-6-carbohydrazide (M4), in the presence of potassium dichromate as the oxidizing agent and sodium hydroxide in a basic medium. This reaction produces a yellow, water-soluble compound with an absorbance at 380 nm. The Beer-Lambert law was applied over the concentration range of 0.5 to 7.5 μg/mL. The recovery was 98.71%, and the correlation coefficient was 0.9955. It was determined that the Sandell sensitivity was 0.0085 μg/cm² and the molar absorptivity was 51599.66 L mol cm. The limits of detection (LOD) and quantification (LOQ) were 0.059 μg/mL and 0.196 μg/mL, respectively. Using the suggested technique, the amount of folic acid found in pharmaceutical formulations has been successfully determined.