Greening Ultrasound-Assisted Extraction for Sorghum Flour Multielemental Determination by Microwave-Induced Plasma Optical Emission Spectrometry

CURTI, MARÍA ISABEL; CORA JOFRE, FLORENCIA; AZCARATE, SILVANA M.; CAMIÑA, JOSÉ M.; RIBOTTA, PABLO D.; SAVIO, MARIANELA

Journal of Analytical Methods in Chemistry

Hindawi

Año: 2021 vol. 2021 p. 1 - 10

2090-8865

Sorghum is the fourth most important cereal produced in Argentina and the fifth worldwide. It has good agronomic characteristics and could be developed in arid areas, allowing a wide geographic distribution. Its starch content, higher than 70%,makes it possible to obtain a good yield of flours. Nutritionally, it should be noted that the grain does not have the protein fractioncalled prolamins, which makes it suitable for consumption by people with celiac disease. +e multielemental compositionconstitutes an important indicator of the nutritional profile of the grains and allows, together with other parameters, to select themost suitable varieties for human consumption. In its determination, the preanalytical stage is decisive to obtain a reliable result.Organic samples are a challenge for sample introduction systems that use plasma-based techniques. As an alternative toconventional pretreatment with a microwave-assisted digestion (MWAD), a greener, quick, and simple treatment is proposed,using ultrasound-assisted extraction (UAE) in diluted acid media. +e UAE method accelerates analysis times, improvesperformance and productivity, and was applied to sorghum samples cultivated in the province of La Pampa (Argentina).Microwave-induced plasma optical emission spectrometry (MIP OES) was employed for the determination of Cu, K, Mg, Mn, P,and Zn. +e detection limits found ranged from 0.6 (Cu) to 89 (P) mg kg−1, and the precision expressed by the relative standarddeviation (RSD) was ≤7.7% (Zn). For validation, a maize reference material (NCS ZC 73010) was evaluated. +e principalcomponent analysis revealed three different groupings related to the sorghum varieties? mineral profile.