Nano Gold Hybrid Polyvinyl Alcohol Films for Sensing of Cu2+ ions

An efficient and eco-friendly approach is adopted for the synthesis of highly stable L-alanine assisted nano gold based polyvinyl alcohol nanocomposite hybrid films (Au/PVA). The - COOH groups of L-alanine and oxygeneous groups of polyvinyl alcohol are utilized for the synthesis of size controlled gold nanoparticles. The as-synthesized nanocomposites show rapid and selective detection of Cu2+ ion in aqueous medium. With addition Cu2+ ion to as-synthesized nanocomposites, the SPR peaks of Au NPs (538 nm) decrease with occurrence of a red shift as well as a new peak is observed at higher wavelength which is due to the aggregation of gold nanoparticles in the nanocomposites hybrid films. Scanning electron microscope (SEM) micrograph and energy dispersive spectroscopy (EDS) reveal the aggregation of gold nanoparticles in the nanocomposite hybrid films. The limit of detection and limit of quantification for Cu2+ ion are 40 nM and 133 nM respectively. This technique for detection of Cu2+ ion in waste water samples is inexpensive and eco-friendly since no any toxic chemicals are used. In the presence of Cu2+ ion, the colour of the hybrid film is changed hence, this method also involves visual detection of Cu2+ ion without use of electrolyte or transducer. Further, many reported methods represent the in situ monitoring of Cu2+ ion, but the present hybrid film can be used for in situ as well as ex situ monitoring of Cu2+ ion.