Spectrophotometric Complexation Studies of Some Transition and Heavy Metals with a New Pyridine Derivative Ligand and Application of It for Solid Phase Extraction of Ultratrace Copper and Determination by Flame Atomic Absorption Spectrometry

摘要

A new pyridine derivative ligand, (E)-(Pyridine-2-ylmethylidene) ({2-(E)-(Pyridine-2-ylmethylidene) amino] ethyl} has been synthesized and kf value of it’s complexes with Cu2+, Ni2+, Cd2+, Zn2+, Co2+, Hg2+ and Ag+ has been determined spectrophometrically. The stability of the complexes to vary in acetonitrile solvent was in the order of Cu2+ > Ni2+ > Cd2+ > Zn2+ > Co2+ > Hg2+ > Ag+, thus because this ligand have good selectivity to copper ion, a simple, reliable and rapid method for preconcentration and determination of the ultratrace amount of copper using octadecyl silica membrane disk modified by this ligand, and determination by flame atomic absorption has been presented. Various parameters including pH of aqueous solution, flow rates, the amount of ligand and the type of stripping reagent were optimized. Under optimum experimental conditions, the breakthrough volume is greater than 2000 ml with an enrichment factor of more than 400 and 0.054 μg×L?1 detection limit. The capacity of the membrane disks modified by 6 mg of the ligand has been found to be330.17 gof copper. The effects of various cationic interferences on the percent recovery of copper ion were studied. The method has been successfully applied for the determination of copper ion in different water samples.