Spectrophotometric determination of butylated hydroxyanisole in pure form and cream formulation via an oxidation-reduction reaction

Three simple, rapid, and reproducible spectrophotometric methods have been developed for the quantitative determination of butylated hydroxyanisole (BHA) in pure form and cream products. The proposed methods are based on the oxidation of the BHA in acidic medium then a known concentration of a dye was added and the unreacted oxidant was estimated using UV-Vis spectrophotometer. Method (1) is based on the oxidation of the BHA by potassium permanganate (1 × 10−3 M KMnO4, 0.6 mL) in the presence of sulfuric acid (2 M H2SO4, 0.4 mL). Then a certain amount of methylene blue (MB, 1 × 10−3 M, 0.4 mL) dye was added to the previous mixture after oxidation to reduce the unreacted oxidant. While in method (2), the oxidation of the BHA is made by cerium ammonium sulfate (CAS, 0.75 mg mL−1, 1.5 mL) in the presence of sulfuric acid (2 M H2SO4, 0.5 mL) and adding certain amount of amaranth dye (AM, 1 × 10−3 M, 0.7 mL) after oxidation to reduce the unreacted oxidant. On the other hand, n-bromosuccinimide (NBS, 5.62 × 10−4 M, 0.8 mL) is used in method (3) for oxidation of BHA in the presence of hydrochloric acid (1.0 M HCl, 0.8 mL) and methyl orange dye (MO, 1 × 10−3 M, 0.8 mL) is added after oxidation process to reduce the unreacted oxidant. For the three methods the optimum sequence of addition of the reagents was crucial and it was BHA-acid-oxidant-dye. Potassium bromide (1%, 0.6 mL) has a significant influence on the method (3) but for the others it has not. Beer's law was obeyed in the concentration range of 2.0-40, 5.0-110, 4.0-60 µg mL−1 for method (1), (2), and (3), respectively. The molar absorptivity values were found to be 4.371 × 103, 1.616 × 103 and 1.434 × 103 L mol−1 cm−1 for methods (1), (2), and (3), respectively. The proposed methods were applied for the determination of BHA in pure form and cream samples