title: Direct colorimetric biosensing of mercury(II) ion based on aggregation of poly-(γ-glutamic acid)-functionalized gold nanoparticles.
abstract: A simple and sensitive method for colorimetric detection of mercury ion (Hg(2+)) has been developed by using a poly (γ-glutamic acid) functionalized gold nanoparticles (PGA-AuNPs) system. Electrostatic self-assembly technique was used to assemble negatively charged PGA on the surface of positively charged CTAB-capped AuNPs. With the increase of Hg(2+) concentration, the color of the solution would progress from light red to purple blue. The results showed that the absorbance ratio (A750/A580) was linear with the Hg(2+) concentration in the range of 0.01-10 μM and from 50 to 300 μM, with the correlation coefficients of 0.998 and 0.991, respectively. The reported probe is suitable for real-time detection of Hg(2+) in water with the limit of detection (LOD) of 1.9 nM obtained by UV-vis spectrum, and exhibits selectivity toward one order of magnitude over other metal ions. This approach was applied successfully to the determination of Hg(2+) in tap water and mineral water, and the recoveries were from 90% to 103% and from 103.53% to 113%, respectively. The proposed method is rapid, low-cost and free of complex equipment, making it possible to analyze Hg(2+) in various water samples.
authors.affiliation: College of Food Engineering, Harbin University of Commerce, Harbin 150076, People's Republic of China. Electronic address: guanhn713@163.com.
authors.forename: Huanan
authors.initials: H
authors.lastname: Guan
authors.affiliation: College of Food Engineering, Harbin University of Commerce, Harbin 150076, People's Republic of China.
authors.forename: Xiaofei
authors.initials: X
authors.lastname: Liu
authors.affiliation: College of Food Engineering, Harbin University of Commerce, Harbin 150076, People's Republic of China.
authors.forename: Wei
authors.initials: W
authors.lastname: Wang
authors.affiliation: College of Food Engineering, Harbin University of Commerce, Harbin 150076, People's Republic of China.
authors.forename: Jinzhong
authors.initials: J
authors.lastname: Liang
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D003124:Colorimetry / Q000379:methods*; D006046:Gold / Q000737:chemistry*; D007477:Ions; D008628:Mercury / Q000032:analysis*; D053768:Metal Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D011099:Polyglutamic Acid / Q000031:analogs & derivatives* / Q000737:chemistry; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared; D014867:Water / Q000737:chemistry
chemical_list: D007477:Ions; C511775:poly(gamma-glutamic acid); D014867:Water; D011099:Polyglutamic Acid; D006046:Gold; D008628:Mercury
keywords: Colorimetric sensing; Gold nanoparticles; Mercury ion (Hg(2+)); Poly-(γ-glutamic acid)