Determination of Cu2+ and Zn2+ in Flaxseed Flour by FAAS and DPASV using Different Sample Treatments

The performance of three conventional treatments, including microwave-assisted acid digestion (MWAD), ultrasoundassisted extraction (UAE) and dry method (DAM) for determination of Cu2+ and Zn2+ in flaxseed meal, was evaluated. Quantification was performed by flame atomic absorption spectrometry (FAAS) and differential pulse anode stripping voltammetry (DPASV). TheMWAD treatment was performed with both concentrated HNO3 (CA) and diluted acid (DA). The concentration of Cu2+ was determined by FAAS and DPASV, by different treatments, ranging from 14.4-26.0 μg g−1 and 8.5-17.9 μg g−1, respectively. The concentration of Zn2+ was possible only by FAAS (28.7-77.4 μg g−1). The highest concentrations were obtained using MWAD. The DAM showed values similar to MWAD for Cu2+, however, for Zn2+ it showed the lowest concentrations. UAE, in turn, showed low concentrations of Zn2+ in relation to MWAD, but similar results to MWAD-DA for Cu2+ in a sample with low fat content. Therefore, both the choice of treatment and the quantification technique play a crucial role in metal determination.