Dispersive liquid-liquid microextraction of multi-elements in seawater followed by inductively coupled plasma-mass spectrometric analysis and evaluation of its greenness

A rapid and efficient dispersive liquid-liquid microextraction method was developed for the simultaneous extraction of V, Co, Ni, Cu, Zn, Se, Mo, Cd, and Pb in seawater samples prior to their determination by inductively coupled plasma-mass spectrometry. The factors affecting the DLLME, such as the volume of chelating reagent, types and volumes of dispersive and extraction solvents, and pH of the sample, were suitably optimized using a univariate approach. Under the optimum conditions, DLLME-ICP-MS exhibited a linear range of 0.1-100 mu g/L for V, Co, Zn, Cd and 0.2-200 mu g/L for Ni, Cu, Se, Mo, Pb, with coefficients of determination (R-2) > 0.9978. The detection limits were in the range of 0.02-0.11 mu g/L, and percentage relative standard deviations (%RSDs) were less than 8.7. The method showed good applicability for real seawater samples with relative recoveries ranging from 85 to 108%. Moreover, it is suitable for small volume samples, and it does not require any modification in the analytical instrument. Finally, the greenness of the proposed DLLME-ICP-MS method was evaluated using tools like Analytical Eco-Scale, Green Analytical Procedure Index, and Analytical Greenness Metric.