A comparative study of different reagentless plasmon sensors based on Ag–Au alloy nanoparticles for detection of Hg

• The Ag–Au alloy nanoparticles were synthesized and characterized.
• Three Ag–AuNPs based plasmonic sensors for detection of Hg(II) ions were compared.
• The probe based on Ag–AuNPs embedded in PVA film was the highest sensitive.
• The developed sensor is reagentless, high sensitive and good selective.

The analytical performance of three Ag–Au alloy nanoparticles (Ag–AuNPs) based plasmonic sensors for the detection of Hg(II) ions were compared. First, Ag–AuNPs were synthesized by the wet chemical method. Then, the nanoparticles were immobilized on a transparent indium tin oxide (ITO) glass surface using poly dimethyl diallyl ammonium chloride (PDDA) as the binding material or by embedding in a poly vinyl alcohol (PVA) film. The optimum composition of the Ag–AuNPs was found to be 0.7 of the Ag content in the alloy. The blue shift of the plasmonic peak wavelength of the Ag–AuNPs could be used for the detection of Hg(II) ions without adding any reagents. The plasmonic sensor based on the Ag–AuNPs/PVA/ITO probe exhibited a much higher sensitive than the Ag–Au colloid or Ag–AuNPs/PDDA/ITO probe. The changes in the peak wavelength were linearly proportional to the logarithm of the Hg(II) ion concentration in the range 0.02–100 ppb, with a detection limit of 0.01 ppb. The proposed sensor was successfully applied to the detection of Hg(II) ions in drinking water, environment, and food samples.

The analytical performance of three Ag–Au alloy nanoparticles (Ag–AuNPs) based plasmonic sensors, including Ag–Au colloid, Ag–AuNPs/PDDA/ITO and Ag–AuNPs/PVA/ITO, for detection of Hg(II) ions were compared. The Ag–AuNPs/PVA/ITO probe was the highest sensitive. Furthermore, it was applied as a reagentless Hg(II) sensor in drinking water and food samples.Figure optionsDownload as PowerPoint slide