Highly sensitive and selective detection of nitrite ions using Fe3O4@SiO2/Au magnetic nanoparticles by surface-enhanced Raman spectroscopy.
A novel and pragmatic method was developed to detect the concentration of nitrite ions using Fe3O4@SiO2/Au magnetic nanoparticles (MNPs) by surface-enhanced Raman scattering (SERS). The as-prepared bifunctional nanocomposites can be used to simultaneously purify target molecules using external magnetic field and produce Raman fingerprint spectrum with trace level of target molecules. In acidic media, 4-aminothiophenol (4-ATP) molecules conjugated on Fe3O4@SiO2/Au MNPs were triggered by nitrite ions to form azo bonds, resulting in three new marker peaks on the SERS spectrum. Under optimized conditions, the detection limit based on the three marker peaks were 15.63, 13.69, and 17.77μM, which was much lower than the maximum NO2(-) concentration of 1.0mgL(-1) (71.4μM) allowed in drinking water as defined by U.S. Environmental Protection Agency (EPA). The specificity of this proposed method to detect nitrite ions was demonstrated using common ions as competitors. In addition, the SERS-based technique was successfully employed to detect nitrite ions in pond water, a synthetic urine solution, and pickle brine. Considering its good sensitivity and selectivity, the detection method is well suited for the detection of nitrite ions in real samples without pretreatment steps.
Department of Food Science, University of Massachusetts, 102 Holdsworth Way, Amherst, MA 01003, United States; Department of Food Science, Cornell University, Stocking Hall, Ithaca, NY 14853, United States.
Juhong
J
Chen
Department of Food Science, University of Massachusetts, 102 Holdsworth Way, Amherst, MA 01003, United States.
Shintaro
S
Pang
Department of Food Science, University of Massachusetts, 102 Holdsworth Way, Amherst, MA 01003, United States.
Lili
L
He
Department of Food Science, University of Massachusetts, 102 Holdsworth Way, Amherst, MA 01003, United States; Department of Food Science, Cornell University, Stocking Hall, Ithaca, NY 14853, United States. Electronic address: snugen@cornell.edu.
Sam R
SR
Nugen
D000814:Aniline Compounds / Q000737:chemistry; D060766:Drinking Water / Q000032:analysis*; D006046:Gold / Q000737:chemistry*; D057230:Limit of Detection; D058185:Magnetite Nanoparticles / Q000737:chemistry* / Q000648:ultrastructure; D009573:Nitrites / Q000032:analysis*; D012822:Silicon Dioxide / Q000737:chemistry*; D013059:Spectrum Analysis, Raman / Q000379:methods*; D013438:Sulfhydryl Compounds / Q000737:chemistry; D014874:Water Pollutants, Chemical / Q000032:analysis*
D000814:Aniline Compounds; D060766:Drinking Water; D058185:Magnetite Nanoparticles; D009573:Nitrites; D013438:Sulfhydryl Compounds; D014874:Water Pollutants, Chemical; D006046:Gold; D012822:Silicon Dioxide; C064316:4-aminothiophenol
Diazotization reaction; Gold nanoparticle; Magnetic nanoparticle; Nitrite ion; Surface-enhanced Raman scattering