Selective and Sensitive Colorimetric Recognition of Ba2+ Ion Using Guanine-Functionalized Silver Nanoparticles

Abstract

Herein, a novel silver nanoparticles (Ag NPs) based colorimetric method was explored for selective recognition of Ba2+ ion in water samples using guanine-Ag NPs as a sensor. The colorimetric recognition strategy was based on the significant change in the surface plasmon resonance (SPR) band of guanine-Ag NPs with Ba2+ ion. The electron-rich groups (-NH2, -CO-NH and -NH-) on the surfaces of guanine-Ag NPs allow to act as an excellent probe for selective colorimetric recognition of Ba2+ ion. The absorption ratio at A(504)/A(420) was shown linear response with Ba2+ ion concentration (0.005-0.5 mu M), with limit of detection of 0.003 mu M (3.0 nM). The color change of guanine-Ag NPs in water samples is ascertained facile, rapid, selective and sensitive recognition of Ba2+ ion at trace levels (nanomolar) without use of sophisticated analytical technique. The developed probe simplifies the sample preparations and provides a rapid analytical tool for sensing of Ba2+ ion environmental samples at minimal volume of samples.