title: Analysis of silver nanoparticles in antimicrobial products using surface-enhanced Raman spectroscopy (SERS).
abstract: Silver nanoparticles (AgNPs) are the most commonly used nanoparticles in consumer products. Concerns over human exposure to and risk from these particles have resulted in increased interest in novel strategies to detect AgNPs. This study investigated the feasibility of surface-enhanced Raman spectroscopy (SERS) as a method for the detection and quantification of AgNPs in antimicrobial products. By using ferbam (ferric dimethyl-dithiocarbamate) as an indicator molecule that binds strongly onto the nanoparticles, AgNPs detection and discrimination were achieved based on the signature SERS response of AgNPs-ferbam complexes. SERS response with ferbam was distinct for silver ions, silver chloride, silver bulk particles, and AgNPs. Two types of AgNPs with different coatings, citrate and polyvinylpirrolidone (PVP), both showed strong interactions with ferbam and induced strong SERS signals. SERS was effectively applicable for detecting Ag particles ranging from 20 to 200 nm, with the highest signal intensity in the 60-100 nm range. A linear relationship (R(2) = 0.9804) between Raman intensity and citrate-AgNPs concentrations (60 nm; 0-20 mg/L) indicates the potential for particle quantification. We also evaluated SERS detection of AgNPs in four commercially available antimicrobial products. Combined with ICP-MS and TEM data, the results indicated that the SERS response is primarily dependent on size, but also affected by AgNPs concentration. The findings demonstrate that SERS is a promising analytical platform for studying environmentally relevant levels of AgNPs in consumer products and related matrices.
authors.affiliation: †Stockbridge School of Agriculture, University of Massachusetts, Amherst, Massachusetts 01003, United States.
authors.forename: Huiyuan
authors.initials: H
authors.lastname: Guo
authors.affiliation: ‡Department of Food Science, University of Massachusetts, Amherst, Massachusetts 01003, United States.
authors.forename: Zhiyun
authors.initials: Z
authors.lastname: Zhang
authors.affiliation: †Stockbridge School of Agriculture, University of Massachusetts, Amherst, Massachusetts 01003, United States.
authors.forename: Baoshan
authors.initials: B
authors.lastname: Xing
authors.affiliation: §Department of Analytical Chemistry, The Connecticut Agricultural Experiment Station, New Haven, Connecticut 06511, United States.
authors.forename: Arnab
authors.initials: A
authors.lastname: Mukherjee
authors.affiliation: §Department of Analytical Chemistry, The Connecticut Agricultural Experiment Station, New Haven, Connecticut 06511, United States.
authors.forename: Craig
authors.initials: C
authors.lastname: Musante
authors.affiliation: §Department of Analytical Chemistry, The Connecticut Agricultural Experiment Station, New Haven, Connecticut 06511, United States.
authors.forename: Jason C
authors.initials: JC
authors.lastname: White
authors.affiliation: ‡Department of Food Science, University of Massachusetts, Amherst, Massachusetts 01003, United States.
authors.forename: Lili
authors.initials: L
authors.lastname: He
mesh_terms: D000890:Anti-Infective Agents / Q000032:analysis* / Q000737:chemistry; D002951:Citrates / Q000737:chemistry; D004396:Coloring Agents / Q000737:chemistry; D004125:Dimethyldithiocarbamate / Q000737:chemistry; D006801:Humans; D053768:Metal Nanoparticles / Q000032:analysis* / Q000737:chemistry; D011145:Polyvinyls / Q000737:chemistry; D011759:Pyrrolidines / Q000737:chemistry; D012834:Silver / Q000737:chemistry*; D018030:Silver Compounds / Q000737:chemistry; D013059:Spectrum Analysis, Raman / Q000379:methods*
chemical_list: D000890:Anti-Infective Agents; D002951:Citrates; D004396:Coloring Agents; D004125:Dimethyldithiocarbamate; D011145:Polyvinyls; D011759:Pyrrolidines; D018030:Silver Compounds; C505150:poly(N-vinylpyrrolidine); D012834:Silver; C037548:silver chloride; C011251:ferbam