Resonance Scattering Spectral Detection of Trace Pb2+ Using Aptamer-Modified AuPd Nanoalloy as Probe

The resonance scattering spectral probe for Pb2+ was obtained using aptamer-modified AuPd Nanoalloy. In the pH 7.0 Na2HPO4-NaH2PO4 buffer solution, the aptamer interacted with AuPd nanoalloy particles to form stable aptamer-AuPd nanoalloy probe for Pb2+ that is stable in high concentration of salt. The probe combined with Pb2+ ions to form a G-quadruplex and to release AuPd nanoalloy particles that aggregate to form big particles which led the resonance scattering (RS) intensity enhancing. The reaction solution was filtered by 0.15 mu m membrane to obtain the filtration containing aptamer-AuPd nanoalloy probe that has strong catalytic effect on the electrodeless nickel particle plating reaction between Ni(II) and PO23- that exhibited a strong RS peak at 508 nm. The RS intensity at 508 nm decreased when the Pb2+ concentration increased. The decreased intensity (Delta I-508nm) is linear to the concentration of 0.08-42 nM Pb2+, with regress equation of Delta I-508nm = 16.3c + 1.5, correlation coefficient of 0.9965, and detection limit of 0.04 nM Pb2+. The RS assay was applied to the analysis of Pb2+ in wastewater, with satisfactory results.