title: Ultrasensitive copper(II) detection using plasmon-enhanced and photo-brightened luminescence of CdSe quantum dots.
abstract: Here, we present a simple platform for the use of the enhanced emission of 16-mercaptohexadecanoic acid (16-MHA) capped CdSe quantum dots (QDs) as a probe for ultrasensitive copper(II) detection. In this study, the photoluminescence (PL) of the QDs was first enhanced by Ag nanoprisms which were self-assembled on Si surfaces and then further increased by photobrightening. Using this approach, the control and different analytes could be readily probed all on a single platform using fluorescence microscopy. The enhanced PL intensity of CdSe QDs was selectively quenched in the presence of Cu(2+), accompanied by the emergence of a new red-shifted luminescence band. The quenching mechanism was found to be due to a cation exchange mechanism as confirmed by X-ray photoelectron spectroscopy (XPS) measurements. Herein, we have demonstrated that this simple methodology can offer a rapid and reliable detection of Cu(2+) with a detection limit as low as 5 nM and a dynamic range up to 100 muM in a fixed fast reaction time of 5 min. The potential applications of this technique were tested in two ways, for mixed-ion solutions and in physiological fluids, and both experiments exhibited good selectivity toward Cu(2+).
authors.affiliation: Department of Chemistry, Texas A&M University, PO Box 30012, College Station, Texas 77842-3012, USA.
authors.forename: Yang-Hsiang
authors.initials: YH
authors.lastname: Chan
authors.forename: Jixin
authors.initials: J
authors.lastname: Chen
authors.forename: Qingsheng
authors.initials: Q
authors.lastname: Liu
authors.forename: Stacey E
authors.initials: SE
authors.lastname: Wark
authors.forename: Dong Hee
authors.initials: DH
authors.lastname: Son
authors.forename: James D
authors.initials: JD
authors.lastname: Batteas
mesh_terms: D019187:Cadmium Compounds / Q000737:chemistry*; D003300:Copper / Q000032:analysis* / Q000737:chemistry; D005456:Fluorescent Dyes / Q000737:chemistry*; D057230:Limit of Detection; D049449:Luminescence; D010169:Palmitic Acids / Q000737:chemistry; D056951:Photoelectron Spectroscopy; D045663:Quantum Dots; D018036:Selenium Compounds / Q000737:chemistry*
chemical_list: C450319:16-mercaptohexadecanoic acid; D019187:Cadmium Compounds; D005456:Fluorescent Dyes; D010169:Palmitic Acids; D018036:Selenium Compounds; D003300:Copper; C058667:cadmium selenide