Development of an Eco-friendly Sample Preparation protocol for metals determination in food samples: Oxygen Pressurized Single Reaction Chamber using Diluted Nitric Acid Cezar Augusto Bizzi, Matheus Felipe Pedrotti, Diogo Maurício Betiolo, Mariele Samuel Nascimento, Edson Irineu Müller, Giancarlo Cravotto and Erico M. M. Flores Abstract Many efforts have been recently made to improve the digestion efficiency by using powerful equipment or by using auxiliary reagent.