For IL-DLLME under optimum conditions, 10 mL of the sample solution containing Cd2+ or Ni2+ and PAN (10−5mol L−1) was adjusted to pH in a glass test tube with a conical bottom test tube. Using a microsyringe, the mixture of the extraction solvent ([Hmim][PF6]) and disperser solvent (acetonitrile) was rapidly injected into the previously mentioned aqueous sample. A cloudy solution (water, acetonitrile and [Hmim][PF6] ) was formed in the test tube. The ions reacted with chelating reagent and were extracted into the fine droplets of extraction solvent. The resultant was centrifuged for 5 min at 5000 rpm and bulk aqueous phase was then removed by a syringe. Finally, the extract was diluted to 100 μL with ethanol solution …show more content…
The choice of extraction solvent needs the following considerations: extraction capability of interested compounds, low solubility in water such as to prevent the dissolution in the aqueous phase and lower density than water. Hence, 1-Hexyl – 3 – methylimidazolium hexaflorophosphate was selected as the extraction solvent. In dispersive liquid-liquid microextraction, disperser solvent has to be miscible in both aqueous phase (sample solution) and organic phase (extraction solvent) to disperse the extraction solvent more efficiently. Acetonitrile was selected as the disperser …show more content…
3.3 Matrix effect
The effect of foreign ions in dispersive liquid-liquid microextraction of Ni2+ and Cd2+ using PAN were studied in the presence of several amounts of other ions under the optimized conditions. An ion was considered to interfere when its presence produced a variation of more than 5% in the absorbance of the sample. According to the results, the major ions in the nettle herb samples have no obvious influence on Ni2+ and Cd2+ based IL-DLLME under the selected conditions. The results are shown in Table 4.
3.4 Linear equation, correlation coefficient, limit of quantification and