title: Crown ether assembly of gold nanoparticles: melamine sensor.
abstract: Melamine toxicity causing the renal failure and death of animals and humans has recently attracted worldwide attention. Developing an easy, fast, and sensitive method for the routine melamine detection is of great importance. Herein, we report the colorimetric sensing of melamine, based on the 18-crown-6 ether functionalized gold nanoparticles (GNPs) through the formation of cavity complexes with amines. Based on high extinction coefficients and spectral sensitivity of the surface plasmon resonance band of the GNPs, the rapid and sensitive melamine detection was achieved both visually and spectroscopically. Under the optimal conditions, melamine could be selectively detected in a concentration range from 10 to 500 ppb with a limit of detection as 6 ppb (3σ), which is much lower than the strictest melamine safety requirement of 1 ppm. To demonstrate the selectivity and practicality of the method, melamine detection was realized in the real complex samples (dairy) with excellent analyte concentration recovery, indicating its applicability for real-time monitoring of toxins in common products. Crown ether assembly of GNP also opens a new route for the formation of three-dimensional pseudorotaxane-like assemblies of nanoparticles that can be applicable to a variety of amine-bearing ligands.
authors.affiliation: School of Food Science and Technology, State Key Lab of Food Science and Technology, Jiangnan University, Wuxi, JiangSu, 214122, PR China.
authors.forename: Hua
authors.initials: H
authors.lastname: Kuang
authors.forename: Wei
authors.initials: W
authors.lastname: Chen
authors.forename: Wenjing
authors.initials: W
authors.lastname: Yan
authors.forename: Liguang
authors.initials: L
authors.lastname: Xu
authors.forename: Yingyue
authors.initials: Y
authors.lastname: Zhu
authors.forename: Liqiang
authors.initials: L
authors.lastname: Liu
authors.forename: Huaqin
authors.initials: H
authors.lastname: Chu
authors.forename: Chifang
authors.initials: C
authors.lastname: Peng
authors.forename: Libing
authors.initials: L
authors.lastname: Wang
authors.forename: Nicholas A
authors.initials: NA
authors.lastname: Kotov
authors.forename: Chuanlai
authors.initials: C
authors.lastname: Xu
mesh_terms: D015374:Biosensing Techniques / Q000295:instrumentation*; D003124:Colorimetry / Q000295:instrumentation*; D043844:Crown Ethers / Q000737:chemistry*; D004867:Equipment Design; D019544:Equipment Failure Analysis; D005504:Food Analysis / Q000295:instrumentation*; D005506:Food Contamination / Q000032:analysis*; D006046:Gold / Q000737:chemistry; D053758:Nanoparticles / Q000737:chemistry*; D036103:Nanotechnology / Q000295:instrumentation; D014227:Triazines / Q000032:analysis*
chemical_list: D043844:Crown Ethers; D014227:Triazines; D006046:Gold; C011907:melamine