Vortex-assisted matrix solid-phase dispersion for the determination of Cu, Mn, and Zn in maize by high-resolution continuum source atomic absorption spectrometry.

This study reports, for the first time, the development of an environmentally friendly analytical strategy based on vortex-assisted matrix solid-phase dispersion (VA-MSPD) combined with high-resolution continuum source atomic absorption spectrometry (HR-CS AAS) for the determination of Cu and Mn (using graphite furnace atomization) and Zn (using flame atomization) in maize (Zea mays L.) samples. The optimized MSPD conditions were 0.5 g of sample, 0.5 g of diatomaceous earth (DE) as the solid support, 3 min of maceration, 10 mL of ultrapure water as the extraction solution, 3 min of vortex mixing, and 10 min of centrifugation. The graphite furnace temperature program was optimized with pyrolysis temperature of 1100 °C for Cu and 1200 °C for Mn, and atomization temperatures of 2000 °C for Cu and 2200 °C for Mn. The limits of quantification were 0.18, 0.61, and 3.6 μg g-1 for Cu, Mn, and Zn, respectively. Accuracy was evaluated by results comparison with those achieved after microwave-assisted digestion (MAD) and detection by inductively coupled plasma optical emission spectrometry (ICP-OES), showing agreement ranging from 84 to 116%. Analyte concentrations ranged from 0.43 to 2.0 μg g-1 for Cu, from 1.1 to 6.8 μg g-1 for Mn, and from 8.6 to 27 μg g-1 for Zn, with relative standard deviations below 10%. The AGREE and AGREEprep metrics yielded scores of 0.66 and 0.74 for VA-MSPD/HR-CS GF AAS, 0.67 and 0.71 for VA-MSPD/HR-CS F AAS, and 0.54 and 0.33 for MAD/ICP-OES, respectively, demonstrating a greater environmental sustainability of the proposed methods compared with the conventional digestion-based procedure.