Surface-enhanced Raman scattering detection of silver nanoparticles in environmental and biological samples

• Published in: The Science of the total environment 2016-06, Vol.554-555, p.246-252
• Main Authors: Guo, Huiyuan, Xing, Baoshan, Hamlet, Leigh C., Chica, Andrea, He, Lili
• Format: Article
• Language: English
• Subjects: AgNPs; Biological samples; Dimethyldithiocarbamate; Environmental water; Matrix components; Metal Nanoparticles - analysis; Metal Nanoparticles - chemistry; SERS; Silver - analysis; Silver - chemistry; Spectrum Analysis, Raman; Spinacia oleracea; Surface Properties
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2016.02.084

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 0.57mg/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. SERS signal intensity of ferbam indicates the concentration of AgNPs. [Display omitted] •Ferbam was found to be the best indicator for SERS detection of AgNPs.•SERS was able to detect AgNPs in both environmental and biological samples.•Major components in the two matrices had limited effect on AgNP detection.