Colorimetric assay for lead ions based on the leaching of gold nanoparticles.
A colorimetric, label-free, and nonaggregation-based gold nanoparticles (Au NPs) probe has been developed for the detection of Pb(2+) in aqueous solution, based on the fact that Pb(2+) ions accelerate the leaching rate of Au NPs by thiosulfate (S(2)O(3)(2-)) and 2-mercaptoethanol (2-ME). Au NPs reacted with S(2)O(3)(2-) ions in solution to form Au(S(2)O(3))(2)(3-) complexes on the Au NP surfaces, leading to slight decreases in their surface plasmon resonance (SPR) absorption. Surface-assisted laser desorption/ionization time-of-flight ionization mass spectrometry (SALDI-TOF MS) data reveals the formation of Pb-Au alloys on the surfaces of the Au NPs in the presence of Pb(2+) ions and 2-ME. The formation of Pb-Au alloys accelerated the Au NPs rapidly dissolved into solution, leading to dramatic decreases in the SPR absorption. The 2-ME/S(2)O(3)(2-)-Au NP probe is highly sensitive (LOD = 0.5 nM) and selective (by at least 1000-fold over other metal ions) toward Pb(2+) ions, with a linear detection range (2.5 nM-10 muM) over nearly 4 orders of magnitude. The cost-effective probe allows rapid and simple determination of the concentrations of Pb(2+) ions in environmental samples (Montana soil and river), with results showing its great practicality for the detection of lead in real samples.
Institute of Bioscience and Biotechnology, National Taiwan Ocean University, Keelung, Taiwan.
Yi-You
YY
Chen
Huan-Tsung
HT
Chang
Yen-Chun
YC
Shiang
Yu-Lun
YL
Hung
Cheng-Kang
CK
Chiang
Chih-Ching
CC
Huang
D002623:Chemistry Techniques, Analytical / Q000379:methods*; D003124:Colorimetry / Q000379:methods*; D006046:Gold / Q000737:chemistry*; D007854:Lead / Q000032:analysis*; D053768:Metal Nanoparticles / Q000737:chemistry*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods; D020349:Surface Plasmon Resonance / Q000379:methods; D014874:Water Pollutants, Chemical / Q000032:analysis*
D014874:Water Pollutants, Chemical; D007854:Lead; D006046:Gold