Optimized Box-Behnken Design Combined Response Surface Methodology to Determine Calcium and Iron Contents Using Visible, Atomic Emission and Atomic Absorption Spectrophotometry in Vegetables and Wastewater Samples.

The article focuses on the development, optimization, and validation of three analytical methods—visible spectrophotometry, atomic emission spectrophotometry (AES), and atomic absorption spectrophotometry (AAS)—to quantify calcium and iron contents in vegetables and wastewater samples. Using response surface methodology (RSM) combined with Box–Behnken design (BBD), the study optimized key variables such as acid concentration, heating time, and temperature to enhance accuracy and reduce experimental trials. The methods demonstrated high precision, accuracy, and robustness, with calcium and iron contents in vegetables ranging from 0.59–2.68 mg and 35.8–211.5 mg per 100 g, respectively, and were also applicable to wastewater analysis. These validated procedures offer practical tools for quality control in food and environmental industries without requiring prior sample cleanup.