Determination Micro Spectrohotometric of Pyridoxine Hydrochloride and Nicotinamide via Derivative Spectrophotometry First and Second. Tikrit J. Pure Sci. [Internet]. 2023 Feb. 3 [cited 2026 Nov. 8];22(12):79-90. Available from: https://www.tjpsj.org/index.php/tjps/article/view/934