title: Room Temperature Cation Exchange Reaction in Nanocrystals for Ultrasensitive Speciation Analysis of Silver Ions and Silver Nanoparticles.
abstract: To evaluate the toxicity of silver nanoparticles (AgNPs) and Ag(+) and gain deep insight into the transformation of AgNPs in the environment or organisms, ultrasensitive analytical methods are needed for their speciation analysis. About 40-fold of Cd(2+) in CdTe ionic nanocrystals can be "bombarded-and-exploded" (exchanged) in less than 1 min simply by mixing the nanocrystals with Ag(+) solution at room temperature, while this cation exchange reaction did not occur when only silver nanoparticles were present. On the basis of this striking difference, an ultrasensitive method was developed for speciation analysis of Ag(+) and AgNPs in complex matrices. The released Cd(2+) was reduced to its volatile species by sodium tetrahydroborate, which was separated and swept to an inductively coupled plasma mass spectrometer (ICPMS) or an atomic fluorescence spectrometer (AFS) for the indirect but ultrasensitive detection of Ag(+). Owing to the remarkable signal amplification via the cation exchange reaction and the advantages of chemical vapor generation for sampling, the limit of detection was 0.0003 μg L(-1) for Ag(+) by ICPMS, which was improved by 100-fold compared to the conventional method. Relative standard deviations are better than 2.5% at a concentration of 0.5 μg L(-1) Ag(+) or AgNPs regardless of the detector. The proposed method retains several unique advantages, including ultrahigh sensitivity, speciation analysis, simplicity and being organic reagent-free, and has been successfully utilized for speciation analysis of Ag(+) and AgNPs in environmental water samples and paramecium cells.
authors.affiliation: †Key Laboratory of Green Chemistry and Technology of MOE, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, China.
authors.forename: Ke
authors.initials: K
authors.lastname: Huang
authors.affiliation: †Key Laboratory of Green Chemistry and Technology of MOE, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, China.
authors.forename: Kailai
authors.initials: K
authors.lastname: Xu
authors.affiliation: †Key Laboratory of Green Chemistry and Technology of MOE, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Tang
authors.affiliation: §Chemical Metrology, Measurement Science and Standards, National Research Council Canada, Ottawa, Canada, K1A 0R6.
authors.forename: Lu
authors.initials: L
authors.lastname: Yang
authors.affiliation: †Key Laboratory of Green Chemistry and Technology of MOE, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, China.
authors.forename: Jingrong
authors.initials: J
authors.lastname: Zhou
authors.affiliation: †Key Laboratory of Green Chemistry and Technology of MOE, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, China.
authors.forename: Xiandeng
authors.initials: X
authors.lastname: Hou
authors.affiliation: †Key Laboratory of Green Chemistry and Technology of MOE, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, China.
authors.forename: Chengbin
authors.initials: C
authors.lastname: Zheng
mesh_terms: D002412:Cations; D057230:Limit of Detection; D053768:Metal Nanoparticles; D053758:Nanoparticles; D012834:Silver / Q000737:chemistry*; D013696:Temperature
chemical_list: D002412:Cations; D012834:Silver