A greener microwave-assisted extraction method for rapid spectroscopic determination of selected metals in river and freshwater sediment certified reference materials

The current study describes development of novel, cost-effective, rapid and greener microwave-assisted extraction (MW-AE) method using diluted hydrogen peroxide (H₂O₂) and 400 µL of concentrated aqua-regia for the extraction of 10 selected metals (Ba, Cr, Cu, Co Fe, Mn, Ni, Pb, V and Zn) in sediment certified reference materials (CRMs), prior to inductively coupled plasma-optical emission spectroscopic analysis. The optimum extraction conditions were achieved when 0.2 g of sediment was extracted with 1 mol L^?1 of H₂O₂ (12.00 mL) and 400 µL of concentrated aqua-regia, at 180°C microwave extraction temperature for 30 min. Accuracy of the proposed MW-AE method was evaluated by using river (LGC6187) and freshwater (CRM015-050) sediment CRMs. Quantitative extraction recoveries of 80–120% in LGC6187 and 74–124% in CRM0150-050 were obtained with acceptable precision (0.4–1.0%). The proposed extraction method has a clear advantage over classical approaches as 1 mol L^?1 H₂O₂ was used instead of notorious acidic mixture (Hydrochloric acid/ nitric acid/ hydrofluoric). The method detection limits (MDLs) of 0.03–0.9 μg g^?1 were obtained for all the investigated metals and were fairly comparable with the MDLs of the published literature reports. Therefore, the proposed MW-AE method can be routinely used for monitoring of metal ions in various river and fresh water sediments.