Reagents
All solutions were prepared in polypropylene volumetric
flasks using ultra-pure deionized (DI) water. Other reagents
used include:
1. Nitric acid Ultrapure 10 (TAMAPURE, Tama Chemicals Co.,
Kanagawa Japan)
2. Hydrogen peroxide: Ultrapure (30%), (Kanto Chemical Co.,
Tokyo, Japan)
3. Lead (Pb) and cadmium (Cd) stock solutions, 1000 mg/L
(PerkinElmer). Cadmium and lead working solutions were
prepared fresh daily by dilution of the cadmium and lead
stock solutions with 2% (v/v) nitric acid.
4. Matrix modifier: mixtures of palladium [Pd(NO3)2] and
magnesium nitrate [Mg (NO3)2
. 6H20] in 10 % nitric acid
solution for Pb analysis and ammonia phosphate [NH4H2PO4]
and magnesium nitrate [Mg (NO3)2
. 6H20] in 10% nitric acid
solution for Cd analysis.