title: A ratiometric fluorescence nanosensor for highly selective and sensitive detection of selenite.
abstract: The instant and on-site detection of selenium still remains a challenge for environmental monitoring and medical prevention. We herein developed a ratiometric fluorescent nanosensor for accurate and on-site sensing of SeO3(2-) by linking the recognition molecule 3,3'-diaminobenzidine (DAB) onto the surface of carboxyl group modified CdTe@SiO2. The fluorescence of DAB on the surface of silica nanospheres could be selectively and efficiently enhanced by SeO3(2-) through a surface chelating reaction between DAB and SeO3(2-). Thus, in the presence of SeO3(2-), the nanosensor would show two characteristic fluorescence emissions of Se-DAB and CdTe QDs under a single excitation wavelength. The selectivity and the optimal conditions for the detection of SeO3(2-) were carefully investigated. The ratio of F530/F635 linearly increased with increasing SeO3(2-) concentration in the range of 0 to 2.5 μM and the detection limit reaches as low as 6.68 nM (0.53 ppb). This developed nanosensor has the capability of on-site detection in an aqueous system without any separation step. The Se concentrations in selenium-rich food were detected and the results were consistent with the values determined by ICP-AES.
authors.affiliation: Faculty of Material Science and Chemical Engineering, China University of Geosciences, Wuhan 430074, P R China. xktian@cug.edu.cn liyong07@126.com.
authors.forename: Linfeng
authors.initials: L
authors.lastname: Chen
authors.forename: Xike
authors.initials: X
authors.lastname: Tian
authors.forename: Yuan
authors.initials: Y
authors.lastname: Zhao
authors.forename: Yong
authors.initials: Y
authors.lastname: Li
authors.forename: Chao
authors.initials: C
authors.lastname: Yang
authors.forename: Zhaoxin
authors.initials: Z
authors.lastname: Zhou
authors.forename: Xiangwen
authors.initials: X
authors.lastname: Liu