title: Specific ionic effect for simple and rapid colorimetric sensing assays of amino acids using gold nanoparticles modified with task-specific ionic liquid.
abstract: In this study, a novel task-specific ionic liquid functionalized gold nanoparticle (TSIL-GNP) was successfully prepared and applied in the recognition of amino acids. Particularly, the surface of GNP was modified with the ionic liquid containing carbamido and ester group via thiol, which was characterized by Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The stability of this material in aqueous solution improves apparently and can remain unchanged for more than three months. The effect of pH was also discussed in this study. Attractive ionic interaction would effectively weaken intensity of the covalent coupling between the metal ion and the functional groups of amino acids. Thus, TSIL-GNP was successfully applied to recognizing serine, aspartic acid, lysine, arginine, and histidine in the presence of Cu(2+) through distinctive color changes. Suspension would be generated once a spot of cysteine was added into the GNPs solution. Results indicated that it had a good linear relationship between extinction coefficients and concentration of amino acids in a wide range of 10(-3)-10(-6) M. Moreover, the proposed strategy was successfully used to analyze the histidine in urinary samples. In brief, TSIL-GNP is a suitable substrate for discrimination of five amino acids in a rapid and simple way without sophisticated instruments.
authors.affiliation: Department of Chemistry, Zhejiang University, Hangzhou 310027, China.
authors.forename: Datong
authors.initials: D
authors.lastname: Wu
authors.affiliation: Department of Chemistry, Zhejiang University, Hangzhou 310027, China.
authors.forename: Pengfei
authors.initials: P
authors.lastname: Cai
authors.affiliation: Department of Chemistry, Zhejiang University, Hangzhou 310027, China.
authors.forename: Zhihao
authors.initials: Z
authors.lastname: Tao
authors.affiliation: Department of Chemistry, Zhejiang University, Hangzhou 310027, China. Electronic address: panyuanjiang@zju.edu.cn.
authors.forename: Yuanjiang
authors.initials: Y
authors.lastname: Pan
mesh_terms: D000596:Amino Acids / Q000032:analysis*; D003124:Colorimetry / Q000379:methods*; D003300:Copper / Q000737:chemistry; D006046:Gold / Q000737:chemistry*; D006863:Hydrogen-Ion Concentration; D052578:Ionic Liquids / Q000737:chemistry*; D053768:Metal Nanoparticles / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D013056:Spectrophotometry, Ultraviolet; D017550:Spectroscopy, Fourier Transform Infrared
chemical_list: D000596:Amino Acids; D052578:Ionic Liquids; D006046:Gold; D003300:Copper
keywords: Amino acids; Colorimetric sensing; Gold nanoparticles; Task-specific ionic liquids