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

Lugar: Londres; Año: 2021 vol. 2021 p. 1 - 10

2090-8865

Sorghum is the fourth most important cereal produced inArgentina and the fifth worldwide. It has good agronomic characteristics andcould be developed in arid areas, allowing a wide geographic distribution. Itsstarch content, higher than 70%, makes it possible to obtain a good yield offlours. Nutritionally, it should be noted that the grain does not have theprotein fraction called prolamins, which makes it suitable for consumption bypeople with celiac disease. The multielemental composition constitutes animportant indicator of the nutritional profile of the grains and allows,together with other parameters, to select the most suitable varieties for humanconsumption. In its determination, the pre-analytical stage is decisive toobtain a reliable result. Organic samples are a challenge for sampleintroduction systems that use plasma-based techniques. As an alternative toconventional pretreatment with a microwave assisted digestion (MWAD), agreener, quick and simple treatment is proposed, using ultrasound-assisted extraction(UAE) in diluted acid media. The UAE method accelerates analysis times,improves performance and productivity, and was applied to sorghum samplescultivated in the province of La Pampa (Argentina). Microwave-Induced PlasmaOptical Emission Spectrometry (MIP OES) was employed for Cu, K, Mg, Mn, P, Zndetermination. The detection limits found ranged from 0.6 (Cu) to 89 (P) mg kg-1 and the precision expressed by therelative standard deviation (RSD) was ≤ 7.7% (Zn). For validation, a maizereference material (NCS ZC 73010) was evaluated. The principal componentanalysis revealed three different groupings related to the sorghum varieties´mineral profile.