Quantitative detection of nitrate in water and wastewater by surface-enhanced Raman spectroscopy

Abstract

The presence of inorganic nitrogen species in water can be unsuitable for drinking and detrimental to the environment. In this study, a surface-enhanced Raman spectroscopy (SERS) method coupled with a commercially available gold nanosubstrate (a gold-coated silicon material) was evaluated for the detection of nitrate and nitrite in water and wastewater. Applications of SERS coupled with gold nanosubstrates resulted in an enhancement of Raman signals by a factor of ∼10(4) compared to that from Raman spectroscopy. The new method was able to detect nitrate with linear ranges of 1-10,000 mg NO3(-)/L (R(2)= 0.978) and 1-100 mg NO3(-)/L (R(2)= 0.919) for water and wastewater samples, respectively. Among the common anions, phosphate appeared to be the major interfering anion affecting nitrate measurement. Nevertheless, the percentage error of nitrate measurement in wastewater by the proposed SERS method was comparable to that by ion chromatography. The nitrate detection limits in water and wastewater samples were about 0.5 mg/L. The SERS method could simultaneously detect sulfate, which may serve as a reference standard in water. These results suggested that the SERS coupled with nanosubstrates is a promising method to determine nitrate concentrations in water and wastewater.

Tunable deep-UV Raman spectroscopy reveals nitrate photolysis

“…The obtained performance is even comparable with the results achieved by means of Surface Enhanced Raman Spectroscopy. 13 To deeper investigate the UV photolysis process the uniqueness of the tunable laser source is exploited. For this a specific Raman filter is adopted and characterized.…”

Reduced graphene oxide/polypyrrole/nitrate reductase deposited glassy carbon electrode (GCE/RGO/PPy/NR): biosensor for the detection of nitrate in wastewater

“…Thus, the detection and determination of nitrate concentration in different environmental matrices such as water and wastewater, soils sediments and plants are of primary importance. During past and recent years, a number of different methods such as spectrophotometry (Edwards et al 2001;López Pasquali et al 2007;Pasquali et al 2010), gas chromatography coupled with mass spectrometry (Tsikas et al 1997), ion chromatography coupled with electrospray ionization tandem mass spectrometry (Blount and Valentin-Blasini 2006), disk electrode alert system (Soropogui et al 2006), miniaturised photometry (Tu et al 2010), surfaceenhanced Raman spectroscopy (Gajaraj et al 2013), electrochemical (Beer and Sweerts 1989), membrane technology (Rezakazemi et al 2017(Rezakazemi et al , 2018a, electrophoresis (Gao et al 2004), hydrodynamic sequential injection (Somnam et al 2008), fluorescence (Mohr et al 1997;Huber et al 2001), and microplate fluorimetry (Ciulu et al 2018) have been used for the detection of nitrate in different types of samples. However, most of these techniques require expensive instrumentation, and in several circumstances, they are not suitable for instant field tests.…”

Surface Enhanced Raman Spectroscopy Enables Observations of Previously Undetectable Secondary Organic Aerosol Components at the Individual Particle Level

“…The ν(NO3 -) peak red shifted from 1067 cm -1 to 1054 cm -1 , which has been observed previously in enhanced spectra of bulk aqueous nitrate and becomes more prominent with increased enhancement. 26 See Supporting Information for further explanation of the peak shift, which is likely related to whether NO3 -is aqueous 9 and how it binds to the nanoparticle surface Ambient atmospheric particles were collected at a remote northern Michigan forested site, with sampling occurring above the forest canopy. Particles were impacted onto quartz and Ag nanoparticle coated quartz substrates using a Multi Orifice Uniform Deposit Impactor (MOUDI) during a field study at the University of Michigan Biological Station (UMBS) near Pellston, MI.…”