Determination and Molecular Interaction Studies of Folic Acid by UV-Vis Spectroscopy

Folic acid (FA) is a vitamin that is critical for DNA synthesis, cell division, and red blood cell production. A UV–Vis spectrophotometric method was developed for the quantitative determination of FA, and its performance was evaluated in detail. The method exhibited a clear linear response within the concentration range of 9 µM to 0.1 mM, with a coefficient of determination exceeding 0.999. The limit of detection (LOD) and limit of quantification (LOQ) were calculated as 3 µM and 9 µM, respectively, indicating that the sensitivity of the method is adequate for routine laboratory analysis. In addition to method validation, the influence of Vitamin B12 (Vit B12), lactose monohydrate (LM), leucine (Leu), and proline (Pro) was investigated to evaluate their potential effects on the spectrophotometric determination of FA. Precision studies (intra-day and inter-day), together with stability and recovery experiments, confirmed the reliability of the procedure. Tablet recovery results further demonstrated that the method can be applied directly to pharmaceutical formulations without significant interference. Overall, the findings show that this UV–Vis approach provides a practical and reproducible strategy for FA determination, while also allowing the evaluation of interaction-related changes in its electronic absorption behavior.