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Indexed by:Journal Papers

Date of Publication:2019-09-01

Journal:ACS SENSORS

Included Journals:PubMed、SCIE

Volume:4

Issue:9

Page Number:2336-2342

ISSN No.:2379-3694

Key Words:SERS; ratiometric analysis; fluoride ion; 4-mercaptoboric acid; silicon-based chip

Abstract:An innovative ratiometric surface-enhanced Raman scattering (SERS) sensor using a 4-mercaptoboric acid (4-MPBA)-modified silver nanoparticle-decorated silicon wafer (Si@Ag NPs chip) was proposed for the ultrasensitive determination of F- ions in aqueous solutions. The principle of sensing strategy is based on fluoride-induced structural symmetry breaking and charge redistribution of phenylboronic acid, leading to a band shift of the C-C stretching mode of 4-MPBA from 1589 to 1576 cm(-1). Accordingly, a ratiometric signal of the area ratio (A(1576)/A(1589)) between the fluoride-bond MPBA molecules and unoccupied MPBA molecules can be used for the quantitative response of F- ions. In comparison with other SERS-based sensing methods, this ratiometric method can avoid a large error resulting from the inhomogeneity of substrates. Under the optimized analytical conditions, the proposed SERS sensor possesses a quick response to F- ions within 2 min and exhibits high selectivity for F- ions with the determination limit of 10(-8) M, which is over 3 orders of magnitude lower than the World Health Organization (WHO) guideline value for F- ions in drinking water. Of particular significance, the present sensor features favorable recyclability, which preserves suitable reproducibility during 6-time cyclic determination of F- ions. The practical utility of this sensing system for the determination of F- ions was tested with real water and toothpaste samples, and the results demonstrate that this sensor shows high recoveries (90-110%). Given its simple principle and easy operation, the present silicon-based SERS sensor could serve as a promising sensor for various practical applications.