All reagents used were of analytical reagent grade.Ultrapure
distilled water was used throughout the experiment. A1000.0 mgL1
stock standard solution of Co(II) was prepared from pure Co
(NO3)2 6H2O (Merck,Darmstadt,Germany).Priorto the investigations, working standard solutions were obtained by appropriate
stepwise dilution of the stock standard solutions.
The allstandard solutions for FAAS instrument calibrationwere
prepared in ethanol.