Dispersive liquid–liquid microextraction based on the solidification of floating organic drop followed by inductively coupled plasma-optical emission spectrometry as a fast technique for the simultaneous determination of heavy metals

Abstract

A simple, rapid and efficient dispersive liquid-liquid microextraction based on the solidification of floating organic drop (DLLME-SFO) method, followed by inductively coupled plasma-optical emission spectrometry (ICP-OES) was developed for the simultaneous preconcentration and determination of heavy metals in water samples. One variable at a time method was applied to select the type of extraction and disperser solvents. Then, an orthogonal array design (OAD) with OA(16) (4(5)) matrix was employed to study the effects of different parameters on the extraction efficiency. Under the best experimental conditions (extraction solvent: 140microL of 1-undecanol; disperser solvent: 2.0mL of acetone; ligand to metal mole ratio: 20; pH: 6 and without salt addition), the enhancement factor ranged from 57 to 96. The calibration graphs were linear in the range of 0.5-250microgL(-1) for Mn, 1.25-250microgL(-1) for Cr, Co and Cu with correlation coefficient (r) better than 0.990. The detection limits were between 0.1 and 0.3microgL(-1). Finally, the developed method was successfully applied to extraction and determination of the mentioned metal ions in the tap, sea and mineral water samples and satisfactory results were obtained.