title: Recognition of potassium ion in water by 15-crown-5 functionalized gold nanoparticles.
abstract: Reported here is an efficient recognition of K+ by 15-crown-5 functionalized gold nanoparticles in aqueous matrix containing physiologically important cations, such as Li+, Cs+, NH4+, Mg2+, Ca2+, and excess amount of Na+. Upon exposure to K+, the colloidal solution changes from red to blue, in response to surface plasmon absorption of dispersed and aggregated nanoparticles. The concentration ranges of K+ detected in this study are 0.099-0.48 mM and 7.6 microM-0.14 mM, when concentrations of colloidal gold are 54.9 and 7.1 nM, respectively. Recognition of K+ and formation of the aggregates are proposed via a sandwich complex of 2:1 between 15-crown-5 moiety and K+. Also discussed is the possibility of a preorganized structure of 15-crown-5 at the water-organic interface for the efficient complexation with K+.
authors.affiliation: Department of Chemistry, National Tsing Hua University, Hsinchu, Taiwan, ROC.
authors.forename: Sui-Yi
authors.initials: SY
authors.lastname: Lin
authors.forename: Shi-Wei
authors.initials: SW
authors.lastname: Liu
authors.forename: Chia-Mei
authors.initials: CM
authors.lastname: Lin
authors.forename: Chun-hsien
authors.initials: CH
authors.lastname: Chen
mesh_terms: D015374:Biosensing Techniques / Q000379:methods*; D004988:Ethers, Cyclic / Q000737:chemistry; D017979:Gold Colloid / Q000737:chemistry*; D036103:Nanotechnology; D011188:Potassium / Q000032:analysis* / Q000378:metabolism; D013438:Sulfhydryl Compounds / Q000737:chemistry; D014867:Water
chemical_list: D004988:Ethers, Cyclic; D017979:Gold Colloid; D013438:Sulfhydryl Compounds; D014867:Water; D011188:Potassium