Cadmium determination based on silver nanoparticles modified with 1,13-bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane

We propose a simple, fast and sensitive colorimetric method for the determination of Cd2+ using 1,13-bis(8-quinolyl)-1,4,7,10,13-pentaoxatridecane modified silver nanoparticles. The addition of Cd2+ causes the aggregation of AgNPs, while other ions do not have such effect. As a result, the color of the solution changes from yellow to red which can be detected using naked eye or by UV-Vis spectroscopy. The aggregation of the AgNPs is confirmed by UV-Vis and transmission electron microscopy. Limit of detection is found to be 0.016 mu M for Cd2+ ions. A linear calibration plot is correlated to the concentration of cadmium ion in the 0.5-6.0 mu M range with the naked-eye detection limit of 2.0 mu M. The method was successfully applied to determine Cd2+ in water and urine samples and gave recoveries that ranged from 93.3 to 98.6%.