title: Modification-free and N-acetyl-L-cysteine-induced colorimetric response of AuNPs: A mechanistic study and sensitive Hg(2+) detection.
abstract: A facile yet sensitive and selective method was proposed for Hg(2+) detection based on N-acetyl-L-cysteine(NAC)-induced colorimetric response of AuNPs. The proposed method can be easily performed by introducing the premixing of NAC and Hg(2+) into as-prepared citrate-capped AuNPs solution. A combination of experimental and theoretical studies was applied to illustrate the mechanism of this AuNPs colorimetric system. The strong interaction of NAC and AuNPs through Au-S bond could lead to the aggregation of AuNPs, but the formation of NAC-Hg-NAC complex decreased the affinity between NAC and AuNPs and resulted in an anti-aggregation effect. Therefore, the color of the AuNPs solution would progress from purple to red with the increase of Hg(2+) concentration. The proposed method had a high sensitivity with a limit of detection of 9.9nM. Coexistent metal ions, including Cd(2+), Mn(2+), Al(3+), Ag(+), K(+), Mg(2+), Ca(2+), Cr(3+), Cu(2+), Fe(3+), Pb(2+), Ni(2+) and Zn(2+), did not interfere with the detection of Hg(2+). This method can be used to monitor Hg(2+) in tap water.
authors.affiliation: Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, China.
authors.forename: Jie
authors.initials: J
authors.lastname: Tang
authors.affiliation: Analytical & Testing Centre, Sichuan University, Chengdu, Sichuan 610064, China.
authors.forename: Peng
authors.initials: P
authors.lastname: Wu
authors.affiliation: Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, China; Analytical & Testing Centre, Sichuan University, Chengdu, Sichuan 610064, China.
authors.forename: Xiandeng
authors.initials: X
authors.lastname: Hou
authors.affiliation: Key Laboratory of Green Chemistry & Technology, Ministry of Education, College of Chemistry, Sichuan University, Chengdu, Sichuan 610064, China. Electronic address: xukailai@scu.edu.cn.
authors.forename: Kailai
authors.initials: K
authors.lastname: Xu
mesh_terms: D000111:Acetylcysteine / Q000737:chemistry*; D002623:Chemistry Techniques, Analytical / Q000379:methods*; D003124:Colorimetry; D006046:Gold / Q000737:chemistry*; D008628:Mercury / Q000032:analysis*; D053768:Metal Nanoparticles / Q000737:chemistry*
chemical_list: D006046:Gold; D008628:Mercury; D000111:Acetylcysteine
keywords: AuNPs; Colorimetric detection; Mercury; N-acetyl-L-cysteine