Analyte Induced shift in Localized Surface Plasmon Resonance of Silver Nanoparticles in Ammonia and Indole-3- Acetic Acid (IAA) Solution

Abstract

A simple strategy for the detection of a simple molecule like ammonia and a phytohormone indole-3-acetic acid(IAA) in solution was proposed based on the localized surface plasmon resonance light scattering (LSPR-LS) of the silver nanoparticles (AgNPs). Citrate capped silver nanoparticles were prepared by chemical reduction, which are found to be30-40 nm in size. The AgNPs were shown to be spherical in shape and fairly monodispersed by scanning electron microscope (SEM) and transmission electron microscopy (TEM). The crystalline nature of silver nanoparticles was characterized using powder X-ray diffraction technique. UV-Visible spectrophotometer was used to study the Sensing of ammonia and IAA in solution. The detection limit of aqueous ammonia and indole-3- acetic acid was in the range of 10^-4M and 10^-3M respectively at room temperature. The silver nanoparticles were found to act as aggregation sensor for the above analytes. Thus, this method provides means for sensing the presence of the growth hormone IAA in resinous plant material, plant extracts and bacterial excretions and low ammonia level in biological fluids, such as plasma, sweat, saliva, cerebrospinal liquid or biological samples in general for various biomedical applications.