SERS-active Ag Nanostars Substrates for Sensitive Detection of Ethyl Carbamate in Wine

Abstract

A simple and sensitive surface-enhanced Raman scattering (SERS) method for the detection of ethyl carbamate (EC) is reported in this work. Star-shaped silver nanostars (Ag NSs) were used as a novel SERS substrate. In comparison to other plasmonic nanoparticles (NPs), including Au NPs, Au NSs and Ag NPs, Ag NSs exhibit best SERS activity. Raman signal of EC at a trace level can be enhanced by several orders of magnitude with the help of Ag NSs. The Raman intensity of EC increased linearly with an increase of the EC concentration in the range from 5 × 10(-9) mol L(-1) to 1.0 × 10(-4) mol L(-1) with detection limit (LOD) of 1.37 × 10(-9) mol L(-1) (S/N = 3). The developed SERS approach also has the advantages of being simple, fast and requiring less amount of the sample. It could serve as a useful technology for the rapid determination of EC in both alcoholic beverages and fermented food.

Surface Plasmon Resonances in Silver Nanostars

“…In the calculations, we used the arms length as nm, i.e., the tip to tip length is 220 nm, and a circular cross-section with diameter 38 nm, taken from the TEM images. A tail was present in for all the Ag-NSs, which clearly indicates that it is not a consequence of a mixture of Ag-NSs with different numbers of arms as supposed in previous works [ 13 , 26 , 27 , 28 ]. The more intense band near nm in Figure 1 a is well captured for all the stars considered and polarizations, but the smaller band in the numerical results is not observable in the experimental results.…”

“…This dependence has motivated the synthesis of metallic NPs with different morphologies [ 13 , 24 ], especially the highly anisotropic NPs such as nanostars (NSs) and nanoplates (NPLs), where the field enhancement of the tip plasmons may result in more efficient SERS [ 25 ]. In one of the latest advances [ 13 ], silver nanostars (Ag-NSs) have provided high SERS performance [ 26 , 27 , 28 ]. The work in this field has been focused on the control of morphology and empirical mechanisms to further enhance the electromagnetic field, while less attention has been given to a theoretical interpretation of some of the observed phenomena.…”

“…The work in this field has been focused on the control of morphology and empirical mechanisms to further enhance the electromagnetic field, while less attention has been given to a theoretical interpretation of some of the observed phenomena. For example, the extinction spectra of Ag-NSs display a tail at large wavelengths ( nm) which is attributed to nanoparticle aggregation and scattering by different morphologies of Ag-NSs and tip sharpnesses [ 13 , 26 , 27 , 28 ].…”

Expedite SERS Fingerprinting of Portuguese White Wines Using Plasmonic Silver Nanostars

“…To avoid laborious and/or costly sample analysis, including pre-treatment processes, spectra were analyzed by PCA, a projection method that provides the best fit of data distribution (Biancolillo and Marini, 2018). This fingerprinting technique is much more expedite than the more common analysis of specific wine components, implying separation and pre-concentration procedures, before applying the sample on SERS substrates (Chen et al, 2016; Li et al, 2016).…”

Detection of ethyl carbamate in liquors using surface-enhanced Raman spectroscopy

“…Li applied Ag nanostar substrates for detection of EC in wine. The Raman intensity was increased linearly with an increase of EC concentration range from 5 × 10 −9 M to 1 × 10 −4 M and the detection limit was 1.37 × 10 −9 M. However, the synthesis of Ag nanostars required stirring for at least 48 h, which was very time consuming [26]. It is necessary to develop a rapid and facile synthesis of nanostructure substrates for EC detection.…”