Selective Preconcentration and Solid Phase Extraction of Ultra Trace Copper(II)from Natural Water and Human Hair and Determination by Atomic Absorption Spectroscopy

摘要

A novel selective and sensitive method for the determination of copper at ng L~(-1)level was developed,using solid phase extraction and flame atomic absorption spectrometry.Copper(II)ions are adsorbed quantitatively during passage of aqueous samples through octadecyl silica membrane disks modified with a new Schiff base 4-(4-chloro-phenylazo)-2-[(4-hydroxy-phenylamino)methyl]phenol.The modified disk is highly selective for Cu(II)and has been used for preconcentrating copper ion prior to this determination by flame atomic absorption spectrometry.The calibration range for Cu(II)was linear up to 1-80 ng/mL and with a 3 s detection limit of 0.2 ng/mL of copper.The recovery of the copper from aqueous solution on the membrane disk modified with 7 mg Schiff base was quantitative over the pH range 4-7.The maximum capacity of the membrane disks modified by 7 mg of Schiff base was found to be 180 Hg of copper.The method was applied to the extraction and determination of copper in natural water and human hair samples.