Determination of trace amounts of Cu2+, Ni2+, and Mn2 ions after preconcentration onto PAN-immobilized organo nanoclay as a new sorbent.

Daryoush Afzali, Ali Mostafavi

Index: J. AOAC Int. 91(6) , 1430-4, (2008)

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Abstract

The application of organo nanoclay 1-(2-pyridylazo)-2-naphthol (PAN)-immobilized as a new, easily prepared, and stable solid sorbent for preconcentration of trace amounts of Cu2+, Ni2+, and Mn2+ ions in aqueous solution is presented. The organo nanoclay was prepared by adding tetradecyldimethylbenzylammonium chloride onto montmorillonite and then saturating with PAN. A simple, rapid, selective, sensitive, and economical method was developed for the simultaneous separation of trace amounts of copper, nickel, and manganese in aqueous medium using PAN as an analytical reagent. The sorption was quantitative in the pH range of 6-9.5, and quantitative desorption occurred instantaneously with 5.0 mL 3 M HNO3. Linearity was maintained at 0.26-37 ng/mL for copper, 1-52 nglmL for nickel, and 0.2-21 ng/mL for manganese in the original solution. The detection limits were 0.04 ng/mL for Cu(II), 0.15 ng/mL for Ni(II), and 0.03 ng/mL for Mn(II) in the original solution (2delta(bl); delta = standard deviation and bl = blank). Various parameters, such as the effect of pH, breakthrough volume, and interference of a large number of anions and cations, have been studied, and the proposed method was used to determine these metal ions in water and standard samples. Determination of these metal ions in standard samples showed that the proposed method has good accuracy.