Optimized Eco-friendly Sample Preparation Methods for Determining Major and Minor Elements in Cheeses by ICP OES

This work describes the optimization and validation of sample preparation methods for determining major and minor elements in artisanal Brazilian cheese samples by inductively coupled plasma optical emission spectrometry. Three sample preparation methods were optimized and compared: microwave-assisted digestion, ultrasound-assisted extraction, and alkaline solubilization using tetramethylammonium hydroxide. A central composite design was used for the optimization using the R software. The optimal experimental conditions were achieved at 1.58 mL of HNO3 14 mol L−1 and 0.570 g of sample mass for the microwave-assisted digestion (capable of determining Ca, Fe, K, Mg, Na, and P); 3.4 mol L−1 of HNO3, 0.91 mol L−1 of HCl, and 2.5 min for the ultrasound-assisted extraction (capable of determining Ca, K, Na, and Zn); and 21.8