102 ARTICLE Submitted 4 May 2023, Resubmitted 22 August 2023, 2 nd time Resubmitted 18 November 2023, Accepted 29 December 2023, Available online 17 January 2024. Cite: Serafim, W. K. M.; Torres, B. S. S.; Kunst, T. H.; do Nascimento, A. L. S.; da Silva, I. J. S.; Ribeiro, M. A.; Paim, A. P. S. Mineral Composition of Rice, Carrots, and Chayote after Microwave-Assisted Decomposition using Diluted Nitric Acid. Braz. J. Anal. Chem. 2024, 11 (44), pp 102-117. http://dx.doi.org/10.30744/brjac.2179-3425.AR-48-2023 Brazilian Journal of Analytical Chemistry 2024, Volume 11, Issue 44, pp 102-117 doi: 10.30744/brjac.2179-3425.AR-48-2023 Mineral Composition of Rice, Carrots, and Chayote after Microwave-Assisted Decomposition using Diluted Nitric Acid Wellen Karen Marcelino Serafim 1 , Briyitte Sofia Salazar Torres 1 , Taciana Holanda Kunst 1 , Alanna Letícia Sena do Nascimento 2 , Iago José Santos da Silva 3 , Marisilda de Almeida Ribeiro 2 , Ana Paula Silveira Paim* 1 1 Departamento de Química Fundamental, Centro de Ciências Exatas e da Natureza, Universidade Federal de Pernambuco. Av. Prof. Jornalista Aníbal Fernandes, s/n, CEP 50740-540, Recife, PE, Brazil 2 Universidade Federal de Pernambuco, Centro Acadêmico de Vitória. Rua Alto do Reservatório, Alto José Leal, CEP 55608-680, Vitória de Santo Antão, PE, Brazil 3 Departamento de Engenharia Civil e Ambiental, Universidade Federal de Pernambuco. Av. Prof. Moraes Rego, 1235, Cidade Universitária, CEP 50670-901, Recife, PE, Brazil Rice, Carrots, Chayote + Diluited HNO 3 + 30% H 2 O 2 + microwave-assisted acid digestion Cooking: 200 g sample, time: Rice: 30 min Carrot: 20 min Chayote: 15 min ICP OES Flame Photometry Cr Cu Al K Na Cd Pb Fe Carrots, chayote, and rice are foods widely consumed by the Brazilian population, so developing analytical methods that allow elemental characterization becomes extremely important. In this work, the sample decomposition method is proposed to prepare samples (raw and cooked) of rice, carrots, and chayote using dilute nitric acid. The samples underwent microwave- assisted acid decomposition (HNO 3 /H 2 O 2 ) for subsequent determination by ICP OES for metals Al, Cd, Cr, Cu, Fe, and Pb and flame photometer for K and Na. Two decomposition methods were used. Method 1: 260 and 500 mg of sample, 3.5 mL of HNO 3 1 mol L -1 , 1.0 mL of H 2 O 2 30% m/m and 3.5 mL of ultrapure water. Method 2: 260 and 500 mg of sample, 5.0 mL of HNO 3 1 mol L -1 , 2.5 mL of H 2 O 2 30% m/m and 0.5 mL of ultrapure water. A factorial design (2 2 ) was also performed to know the effects of some variables on digestion efficiency. Based on the accuracy study using certified reference materials and the analysis of residual acidity and dissolved organic carbon, the condition that presented the best decomposition results was using 5 mL of HNO 3 0.5 mol L -1 and 2.5 mL of H 2 O 2 30% for 100 mg of sample. Quantification limits ranged from 0.14 (Cr) and 3.4 mg kg -1 (Pb), and the correlation coefficient was close to one in all cases. It was also observed that the cooking process increased the concentration of Al, Cd, and Cr and decreased Cu and K for all foods. Keywords: vegetable food, cooking effect, minerals, diluted acid, microwave-assisted digestion This article was submitted to the BrJAC special issue dedicated to the 20 th Brazilian Meeting of Analytical Chemistry (ENQA).