Investigating essential and toxic elements in Antarctic macroalgae using a green analytical method

A systematic study for the determination of essential and toxic elements (such as As, Cd, Cu, Mn, Ni, Pb, V and Zn) in Antarctic macroalgae species (Desmarestia anceps, Iridaea cordata, Palmaria decipiens and Pyropia endiviifolia) was performed. For this purpose, a green sample preparation method combined with a high-sensitivity detection technique (inductively coupled plasma mass spectrometry) was used. By using the microwave-assisted digestion combined with ultraviolet radiation (MW-UV) method, 700 mg of macroalgae were digested using a diluted HNO3 solution (2 mol L-1). The accuracy was evaluated by analysis of certified reference materials of aquatic plant (BCR 060) and apple leaves (NIST 1515). Agreement with reference or informed values for all analytes ranged from 94 to 106%, except for As and Mo in BCR 060. The results were also compared with those obtained by the reference method, which did not present a significant difference (t test, 95% confidence level). Based on the results, analysed samples showed considerable variations in regards to the concentrations of Zn, Ni and Mn. Moreover, a relatively high concentration of As in Desmarestia anceps and Pyropia endiviifolia was observed. The results for most of the analytes in Antarctic macroalgae were in agreement with other studies that have been published in literature. In addition, the proposed method was suitable for determining toxic and essential elements in Antarctic macroalgae reducing reagent consumption and waste generation, which is in agreement with the green chemistry recommendation.