the extraction is most
efficient at pH 7-9 on using either chloroform or the ionic
liquid. Moreover the extraction of Pb(II) with the ionic
liquid [TOA][DBS] is distinctly more efficient than with the
traditional solvent, chloroform. Figures with similar trends
were obtained for extraction of Hg(II), Cu(II) and Cd(II)
with extraction exceeding 95% within the pH range 7 to 9.
This is due to formation of dithizonate at these pH values
which are fairly above the pKa of dithizone (5.77 ± 0.25)