Derivative spectrophotometric method for simultaneous determination of ascorbic acid and folic acid in the pharmaceutical formulation; Comparative greenness assessment

• The proposed technique provides a straightforward and accurate approach for the simultaneous determination of ascorbic acid and folic acid without pretreatment or any separation procedure.a. • The proposed technique minimizes the use of harmful or toxic organic solvents, making it a green analytical procedure and considered an environmentally friendly technique. • Some statistical measurements have been applied to evaluate the greenness profile of the proposed technique. Ascorbic acid and folic acid are frequently included together in multivitamin pharmaceutical products due to their complementary roles in maintaining human health. The quality and efficiency of supplements can vary depending on the manufacturer and the specific ingredients used, which are vital factors to consider. This research presents the development and validation of a simple, sensitive, accurate, and environmentally friendly derivative spectrophotometric technique utilizing the zero-crossing method for the simultaneous determination of ascorbic acid and folic acid, both in their pure form and in pharmaceutical formulations. The derivative spectrophotometry technique demonstrated measurable amplitude and substantial linearity for both analytes. At the zero-crossing points of folic acid (249.6 and 281 nm), ascorbic acid showed a measurable amplitude with a linear range of 0.17–12.0 μg/mL and 0.37–12 μg/mL, and detection limits of 0.057 μg/mL and 0.121 μg/mL, respectively. Conversely, folic acid displayed an observable amplitude at the zero-crossing point of ascorbic acid (265.6 nm) with a linear range from 0.26 to 15.0 μg/mL and a detection limit of 0.088 μg/mL. The greenness of the proposed derivative spectrophotometric method was evaluated using the White Analytical Chemistry (WAC) framework and the Green Analytical Procedure Index (GAPI). The method scored highly in both evaluations, confirming its minimal environmental impact and alignment with the principles of Green Analytical Chemistry. The GAPI assessment highlighted low environmental and health risks throughout the analytical process, making this method a green and sustainable choice for the simultaneous determination of ascorbic acid and folic acid. The method was successfully applied to synthetic laboratory mixtures and formulated tablets, showing excellent precision, accuracy, and recovery, while also being environmentally friendly.