title: Surface-enhanced Raman scattering detection of silver nanoparticles in environmental and biological samples.
abstract: Growing concerns over the potential release and threat of silver nanoparticles (AgNPs) to environmental and biological systems urge researchers to investigate their fate and behavior. However, current analytical techniques cannot meet the requirements for rapidly, sensitively and reliably probing AgNPs in complex matrices. Surface-enhanced Raman spectroscopy (SERS) has shown great capability for rapid detection of AgNPs based on an indicator molecule that can bind on the AgNP surface. The objective of this study was to exploit SERS to detect AgNPs in environmental and biological samples through optimizing the Raman indicator for SERS. Seven indicator molecules were selected and determined to obtain their SERS signals at optimal concentrations. Among them, 1,2-di(4-pyridyl)ethylene (BPE), crystal violet and ferric dimethyl-dithiocarbamate (ferbam) produced the highest SERS intensities. Further experiments on binding competition between each two of the three candidates showed that ferbam had the highest AgNPs-binding ability. The underlying mechanism lies in the strong binding affinity of ferbam with AgNPs via multiple sulfur atoms. We further validated ferbam to be an effective indicator for SERS detection of as low as 0.1mg/L AgNPs in genuine surface water and 0.57 mg/L in spinach juice. Moreover, limited interference on SERS detection of AgNPs was found from environmentally relevant inorganic ions, organic matter, inorganic particles, as well as biologically relevant components, demonstrating the ferbam-assisted SERS is an effective and sensitive method to detect AgNPs in complex environmental and biological samples.
authors.affiliation: Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003, USA.
authors.forename: Huiyuan
authors.initials: H
authors.lastname: Guo
authors.affiliation: Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003, USA. Electronic address: bx@umass.edu.
authors.forename: Baoshan
authors.initials: B
authors.lastname: Xing
authors.affiliation: Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003, USA.
authors.forename: Leigh C
authors.initials: LC
authors.lastname: Hamlet
authors.affiliation: Stockbridge School of Agriculture, University of Massachusetts, Amherst, MA 01003, USA.
authors.forename: Andrea
authors.initials: A
authors.lastname: Chica
authors.affiliation: Department of Food Science, University of Massachusetts, Amherst, MA 01003, USA. Electronic address: lilihe@foodsci.umass.edu.
authors.forename: Lili
authors.initials: L
authors.lastname: He
mesh_terms: D004125:Dimethyldithiocarbamate; D053768:Metal Nanoparticles / Q000032:analysis* / Q000737:chemistry; D012834:Silver / Q000032:analysis* / Q000737:chemistry; D013059:Spectrum Analysis, Raman; D013499:Surface Properties
chemical_list: D004125:Dimethyldithiocarbamate; D012834:Silver; C011251:ferbam
keywords: AgNPs; Biological samples; Environmental water; Matrix components; SERS