New Potentials in the Extraction of Trace Metal Using Natural Deep Eutectic Solvents (NADES)

The aim of the study was to concentrate on developing new solvents for extraction of selected metal complexes from young barley. Estimation of the amount of elements in compound, not only their total concentration, is very important because only a part from total content of metal is absorbed by human organism. At the beginning, the total amount of elements in young barley was established as 16.69 ± 0.22 μg g−1 (RSD 1.36%) for copper, 156.29 ± 0.82 μg g−1 (RSD 0.52%) for manganese, 155.35 ± 1.29 μg g−1 (RSD 0.83%) for zinc, 9.10 ± 0.21 μg g−1 (RSD 2.36%) for molybdenum, and 0.35 ± 0.01 μg g−1 (RSD 1.63%) for cobalt. The LOD of analyzed elements were as follows (μg L−1): Mn 0.59, Co 0.05, Cu 0.33, Zn 1.2, and Mo 0.12. The LOQ of studied metals were as follows (μg L−1): Mn 1.9, Co 0.18, Cu 1.1, Zn 4.0, and Mo 1.4. After that, the most suitable solvents were identified. The determination of total and extractable amount of metals in young barley was carried out by standalone inductively coupled plasma mass spectrometry (ICP-MS). In addition, a complementary analysis of extracted metal complexes was performed using size exclusion chromatography coupled with inductively coupled plasma mass spectrometry (SEC-ICP-MS) method. It was confirmed that the natural deep eutectic solvents (NADES) are able to extract different metal and metal species in comparison with commonly used solvents. The study indicated that extraction by using the NADES has been successfully applied for determination of metals and metal complexes in young barley.