Novel ion imprinted polymer coated multiwalled carbon nanotubes as a high selective sorbent for determination of gold ions in environmental samples

In this work, for the first time an ion imprinted polymer (IIP) has been synthesized for gold ions preconcentration and determination. In order to increase extraction efficiency and improve the figures of merit, this polymer has been grafted on multiwalled carbon nanotube and was characterized by infrared (IR) spectroscopy, high resolution transmission electron microscopy (HRTEM), scanning electron microscopy (SEM), elemental analysis (CHN) and thermal analysis (TGA/DSC). The application of this sorbent has been investigated for rapid extraction, preconcentration and determination of trace amounts of gold ions in environmental samples. The optimum conditions, including pH of sample, eluent type and concentration, also eluent and sample flow rates and the least amounts of eluent for desorption of gold ions were obtained. The effects of various cationic interferences on the adsorption of gold ions, especially platinum and palladium ions, as the most important interferences, were evaluated. The analytical efficiency value of gold ions was 98.3% in the optimum condition. The limit of detection (LOD) was less than 0.041 ng mL(-1) for gold extraction. The maximum capacity of this IIP modified nano-tubes were obtained more than 67 mg g(-1). The relative standard deviation for this method was determined to be 1.14. Furthermore, the accuracy of this method was confirmed using various standard reference materials. This method was successfully applied for determination of gold ions in natural samples. (C) 2012 Elsevier B.V. All rights reserved.