Our preliminary observation showed that Aliquat 336 acts as a
disperser by accelerating the formation of fine droplets of the
extraction solvent in aqueous sample as well as forming an ion
pair with the blue product. Despite this the influence of several
conventional disperser solvents such as methanol, ethanol, acetonitrile
and acetone was also investigated. For this purpose,
supplementary experiments were performed through injection
of a mixture containing appropriate amount of CCl4, Aliquat 336
and mentioned disperser solvents. The results showed that carbon
tetrachloride is partially dissolved in the disperser solvent and
migrates into aqueous phase and the dissolved carbon tetrachloride
is not sedimented down well and the extraction efficiency is
decreased. Therefore, the suggested method was carried out by
injecting the extraction solvent (without any disperser solvent)
and only containing appropriate amount of Aliquat 336 to the
sample solutions. Unlike using conventional disperser solvents,
very small volume of CCl4 is dissolved in aqueous solutions in the
presence of Aliquat 336, and the volume of sedimented phase was
almost equal to the volume of injected CCl4, which is an advantage
for the proposed method.