title: Label-free fluorescent sensor for mercury(II) ion by using carbon nanotubes to reduce background signal.
abstract: A simple, selective and sensitive turn-on fluorescent sensor for the detection of mercury(II) ion was developed using Sybr Green I as the signal reporter and SWCNTs as the quencher. Due to the affinity of SWCNTs towards ssDNA and organic dye, Sybr Green I, thymine-rich ssDNA and SWCNTs could form a self-assembly of three components, resulting in fluorescence quenching. Upon addition of another thymine-rich ssDNA and mercury(II) ion, formation of dsDNA via T-Hg(2+)-T base pairs enabled Sybr Green I to intercalate into the dsDNA, resulting in the restoration of fluorescence. SWCNTs were found to reduce the background signal and improve the analytical sensitivity. A linear relationship between the fluorescence intensity and the concentration of mercury(II) ion was observed in the range of 20-1250 nM (R = 0.9985) with a detection limit of 7.9 nM. The proposed method was applied to detect mercury(II) ion in tap water samples with good results.
authors.affiliation: Ministry of Education Key Laboratory of Analysis and Detection for Food Safety, Fujian Provincial Key Laboratory of Analysis and Detection Technology for Food Safety, and Department of Chemistry, Fuzhou University, Fuzhou, Fujian 350108, China. lqguo@fzu.edu.cn
authors.forename: Liang-qia
authors.initials: LQ
authors.lastname: Guo
authors.forename: Na
authors.initials: N
authors.lastname: Yin
authors.forename: Dan-dan
authors.initials: DD
authors.lastname: Nie
authors.forename: Jin-rui
authors.initials: JR
authors.lastname: Gan
authors.forename: Mei-jin
authors.initials: MJ
authors.lastname: Li
authors.forename: Feng-fu
authors.initials: FF
authors.lastname: Fu
authors.forename: Guo-nan
authors.initials: GN
authors.lastname: Chen
mesh_terms: D052160:Benzothiazoles; D004277:DNA, Single-Stranded / Q000737:chemistry; D003959:Diamines; D005456:Fluorescent Dyes / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D008628:Mercury / Q000032:analysis*; D037742:Nanotubes, Carbon / Q000737:chemistry*; D009930:Organic Chemicals / Q000737:chemistry; D011804:Quinolines; D013050:Spectrometry, Fluorescence / Q000379:methods*; D013941:Thymine / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis*
chemical_list: D052160:Benzothiazoles; D004277:DNA, Single-Stranded; D003959:Diamines; D005456:Fluorescent Dyes; D007477:Ions; D037742:Nanotubes, Carbon; D009930:Organic Chemicals; D011804:Quinolines; D014874:Water Pollutants, Chemical; C098022:SYBR Green I; D008628:Mercury; D013941:Thymine