Recently, a (SI) Hg CVG technique was reported,
which also eliminates the need for conventional reducing
agents.15-18 Reduction of Hg(II) to Hg(0) was accomplished in a
sonoreactor owing to the reducing gases and radicals formed upon
sonolysis of formic acid added to the sample solution. A drawback
of SI-CVG is that the presence of oxidizing substances in the
sample precludes the reduction of Hg(II) to Hg(0) by ultrasound.
In addition, it is used only in a batch system and is difficult to
couple with flow injection.