Optimization of microwave-assisted extraction procedure for zinc and copper determination in food samples by Box-Behnken design

This article describes the application of response surface methodology (RSM) to the development of a procedure for zinc and copper determination by flame atomic absorption spectrometry (FAAS) in food samples after extraction by a microwave system. A Box-Behnken matrix was used to find optimal conditions for the procedure through a response surface study. Three variables “irradiation power; time; and temperature” were regarded as factors in the optimization study. The working conditions were established as a compromise between optimum values found for each analyte taking into consideration the robustness of the procedure. These values were 97 °C, 90 W and 9.0 min, for temperature, irradiation power and time, respectively. The accuracy of the optimized procedure was evaluated by the analysis of certified reference materials. The method was applied to the determination of copper and zinc in wheat flour and corn flour samples.