title: Colorimetric assay for determination of lead (II) based on its incorporation into gold nanoparticles during their synthesis.
abstract: In this report, we present a new method for visual detection of Pb2+. Gold nanoparticles (Au-NPs) were synthesized in one step at room temperature, using gallic acid (GA) as reducer and stabilizer. Pb2+ is added during the gold nanoparticle formation. Analysis of Pb2+ is conducted by a dual strategy, namely, colorimetry and spectrometry. During Au-NPs synthesis, addition of Pb2+ would lead to formation of Pb-GA complex, which can induce the aggregation of newly-formed small unstable gold nanoclusters. Consequently, colorimetric detection of trace Pb2+ can be realized. As the Pb2+ concentration increases, the color turns from red-wine to purple, and finally blue. This method offers a sensitive linear correlation between the shift of the absorption band (Δλ) and logarithm of Pb2+ concentration ranging from 5.0×10(-8) to 1.0×10(-6) M with a linear fit coefficient of 0.998, and a high selectivity for Pb2+ detection with a low detection limit down to 2.5×10(-8) M.
authors.affiliation: College of Chemistry and Chemical Engineering, Graduate University of Chinese Academy of Sciences, 19A YuQuan Road, Beijing 100049, China. dingnaner@yahoo.com.cn
authors.forename: Nan
authors.initials: N
authors.lastname: Ding
authors.forename: Qian
authors.initials: Q
authors.lastname: Cao
authors.forename: Hong
authors.initials: H
authors.lastname: Zhao
authors.forename: Yimin
authors.initials: Y
authors.lastname: Yang
authors.forename: Lixi
authors.initials: L
authors.lastname: Zeng
authors.forename: Yujian
authors.initials: Y
authors.lastname: He
authors.forename: Kaixiang
authors.initials: K
authors.lastname: Xiang
authors.forename: Guangwei
authors.initials: G
authors.lastname: Wang
mesh_terms: D003124:Colorimetry / Q000295:instrumentation / Q000379:methods; D004305:Dose-Response Relationship, Drug; D060766:Drinking Water / Q000032:analysis / Q000737:chemistry; D004784:Environmental Monitoring / Q000379:methods; D005240:Feasibility Studies; D005707:Gallic Acid / Q000737:chemistry / Q000494:pharmacology; D006046:Gold / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D007854:Lead / Q000032:analysis* / Q000737:chemistry; D053768:Metal Nanoparticles / Q000737:chemistry*; D009994:Osmolar Concentration; D013056:Spectrophotometry, Ultraviolet; D013379:Substrate Specificity; D014466:Ultraviolet Rays
chemical_list: D060766:Drinking Water; D007854:Lead; D005707:Gallic Acid; D006046:Gold