Development and validation of a green UV-Vis spectrophotometric method for the determination of potassium bromate in...

This study hypothesized that a green, sensitive, and cost-effective UV-Vis spectrophotometric method could be developed using promethazine as a chromogenic reagent to accurately quantify potassium bromate in bread. In acidic medium, potassium bromate was found to oxidize promethazine, producing a red-colored compound with maximum absorbance at 515 nm. The method was validated according to Eurachem/CITAC and ICH Q2 (R1) guidelines, evaluating linearity, accuracy, precision, limit of detection, and limit of quantification. The calibration curve was linear over the range of 0.370-2.570 μg/mL with a regression equation of Y = ax + b and correlation coefficient r² = 0.9962. Recovery rates ranged from 82.968 % to 108.542 %, while the limit of detection and limit of quantification were 0.005 μg/g and 0.016 μg/g, respectively. The devised approach was well validated and effectively quantified potassium bromate in bread. The method demonstrated high precision and reliability under the tested conditions. It minimized chemical hazards by using small volumes of reagents in water-based systems. No organic toxic solvents were used, aligning with key green chemistry principles. The greenness evaluation confirmed environmental suitability with an Analytical Eco-Scale score of 76, AGREE score of 0.71, and minimal red hues in the GAPI profile. These results support the hypothesis that promethazine can be effectively used in a sustainable spectrophotometric method for potassium bromate determination in bread.