Khalil , E. and Sultan , S. 2025. Spectrophotometric Determination of hiamin Hydrochloride in Pharmaceutical Preparations by Azo-Coupling Reactions with Sulphacetamide Sodium Reagent. Journal of Wahj Al-Ulom for Pure Sciences. 1, 2 (Jul. 2025). DOI:https://doi.org/10.33899/jwups.v1i2.21900.