Highly sensitive and selective detection of nitrite ions using Fe3O4@SiO2/Au magnetic nanoparticles by surface-enhanced Raman spectroscopy

Abstract

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.

Enhanced Catalytic Reduction of 4-Nitrophenol Driven by Fe3O4-Au Magnetic Nanocomposite Interface Engineering: From Facile Preparation to Recyclable Application

“…Figure 4 e,f shows the TEM images of single Fe 3 O 4 -Au 5 mL and Fe 3 O 4 -Au 60 mL microspheres and corresponding energy-dispersive X-ray (EDS) mapping images of Au, Fe and O elements [ 74 , 75 ]. It could be clearly found that the Fe 3 O 4 hollow microspheres have hollow internal structures, and Au seeds are homogeneously attached to the surfaces of the Fe 3 O 4 hollow microspheres.…”

The Trace Detection of Nitrite Ions Using Neutral Red Functionalized SH-β-Cyclodextrin @Au Nanoparticles

“…The diazonium group between NO 2 − and the primary amine group of NR was more stable in an acid solution [ 49 ]. Compared with other sensors [ 50 , 51 ], this sensor displayed a wide detection range and good sensitivity. Some of the typical methods are summarized in Table S1 (see Supplementary materials) .…”

Phenosafranin-Based Colorimetric-Sensing Platform for Nitrite Detection Enabled by Griess Assay

“…The large conjugate structure of SO (purplish) was diazotized through the Griess assay and formed a blue diazonium salt compound, which produces an obvious color change from purplish to blue and subsequently can be easily identified using the naked eye. The possible incomplete diazotization reaction resulted in a relatively high linear nitrite concentration ranging from 10 to 100 ppm (0.22 to 2.17 mM) in the solid phase, which does not meet the requirements set by the WHO (65.22 µM) and EPA (21.74 µM) [43].…”