Application of modified multiwalled carbon nanotubes as a sorbent for simultaneous separation and preconcentration trace amounts of Au(III) and Mn(II)

Abstract: A solid phase extraction procedure is proposed for simultaneous separation and preconcentration trace amounts of Au(III) and Mn(II) in an aqueous medium by using a column of multiwalled carbon nanotubes modified with the analytical reagent N,N′-bis(2-hydroxybenzylidene)-2,2′(aminophenylthio)ethane. An implementation, it was found that the sorption is quantitative in the pH range 5.0–7.5, whereas quantitative desorption occurs instantaneously with 4.0mL of 0.1molL−1 Na2S2O3. Selected elements were also determined by flame atomic absorption spectrometry. Linearity was maintained between 0.2ngmL−1 to 25μgmL−1 for gold and 0.08ngmL−1 to 5μgmL−1 for manganese in the original solution. Various parameters such as the effect of pH, flow rate, type and amount of eluent, breakthrough volume and interference of a large number of anions and cations on the recovery of the selected ions was studied. Under optimum conditions, the detection limits (3s, n =10) for analytes were 0.03ngmL−1 (gold) and 0.01ngmL−1 (manganese). The method was successfully applied for separation and determination of gold and manganese ions in water and standard samples. [Copyright &y& Elsevier]