title: A silica-based SERS chip for rapid and ultrasensitive detection of fluoride ions triggered by a cyclic boronate ester cleavage reaction.
abstract: Chemical sensing for the convenient detection of trace aqueous fluoride ions (F-) has been widely explored with the use of various sensing materials and techniques. It still remains a challenge to achieve ultrasensitive but simple, rapid, and inexpensive detection of F-for environmental monitoring and protection. Here we reported a novel surface-enhanced Raman scattering (SERS) nanosensor, fluorescein phenylboronic acid covalently linked to 1,4-dimercapto-2,3-butanediol modified Au@Ag NPs by a cyclic boronate ester (Flu-PBA-Diol-Au@Ag NPs), for the rapid and ultrasensitive detection of F-. Once the Flu-PBA approached the surface of Au@Ag NPs, the Raman signals of Flu-PBA were remarkably enhanced due to the strong SERS effect. However, the presence of F-will induce the cleavage reaction of the cyclic boronate ester into the trifluoroborate anion (3F-Flu-PBA) and diol. The 3F-Flu-PBA molecules exfoliated from the surface of Au@Ag NPs, and the SERS signals of the nanosensor were quenched. Following the sensing mechanism, a silica-based SERS chip has been fabricated by the assembly of Flu-PBA-Diol-Au@Ag NPs on a piece of silicon wafer. The silica-based SERS chips showed high sensitivity for aqueous F-, and the limit of detection (LOD) could reach as low as 0.1 nM. Each test using the SERS chip only needs a droplet of 20 μL sample and is accomplished within ∼10 min. The silica-based SERS chip has also been applied to the quantification of F-in tap water and lake water.
authors.affiliation: Department of Applied Chemistry, Anhui Agricultural of University, Hefei, Anhui 230036, China. jianzhang@ahau.edu.cn.
authors.forename: Jian
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Department of Applied Chemistry, Anhui Agricultural of University, Hefei, Anhui 230036, China. jianzhang@ahau.edu.cn.
authors.forename: Lifang
authors.initials: L
authors.lastname: He
authors.affiliation: Department of Applied Chemistry, Anhui Agricultural of University, Hefei, Anhui 230036, China. jianzhang@ahau.edu.cn.
authors.forename: Peirong
authors.initials: P
authors.lastname: Chen
authors.affiliation: Department of Applied Chemistry, Anhui Agricultural of University, Hefei, Anhui 230036, China. jianzhang@ahau.edu.cn.
authors.forename: Chao
authors.initials: C
authors.lastname: Tian
authors.affiliation: CAS Center for Excellence in Nanoscience, Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, China. cljiang@iim.ac.cn.
authors.forename: Jianping
authors.initials: J
authors.lastname: Wang
authors.affiliation: CAS Center for Excellence in Nanoscience, Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, China. cljiang@iim.ac.cn.
authors.forename: Bianhua
authors.initials: B
authors.lastname: Liu
authors.affiliation: CAS Center for Excellence in Nanoscience, Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, China. cljiang@iim.ac.cn.
authors.forename: Changlong
authors.identifier: http://orcid.org/0000-0003-3650-3702
authors.initials: C
authors.lastname: Jiang
authors.affiliation: CAS Center for Excellence in Nanoscience, Institute of Intelligent Machines, Chinese Academy of Sciences, Hefei, Anhui 230031, China. cljiang@iim.ac.cn and School of Chemistry and Chemical Engineering, Anhui University, Hefei, Anhui 230601, China.
authors.forename: Zhongping
authors.initials: Z
authors.lastname: Zhang