2.2. Reagents and solutions
All solutions were prepared with ultra pure water (Ghazi Co.,
Tabriz, Iran). The lead stock solution (1000mgL−1, the standard
solution for the atomic spectroscopy) was purchased
from Merck (Darmstadt, Germany). The working standard
solutions were prepared by serial dilutions of the stock solution
with ultra pure water immediately prior to analysis.
The chelating agent, diethyldithiophosphoric acid (DDTP),
with the density of 1.17 kg L−1 was supplied from Merck.
The rest of the used chemicals were carbon tetrachloride
(analytical grade for determination with dithizone), chloroform
(analytical grade for determination with dithizone),
tetrachloroethylene (analytical grade) and carbon disulfide
(for spectroscopy) as extraction solvent, methanol (for spectroscopy),
ethanol (for spectroscopy), acetone (suprasolv) and