# Recent Developments in Plasmonic Sensors of Phenol and Its Derivatives
## 5 Plasmonic Resonance-Based Raman Sensors for Detection of Phenolic Compounds
### Metal-Organic Frameworks Structure-Introduced Raman Sensors
There are several perspectives to be addressed in future studies: (i) improving optical sensor methods based on pure, noble metal nanomaterials, and hybrid nanostructured materials; (ii) developing more MOFs that exhibit high target sensor; (iii) exhibiting the ability of multiple detections of similar analytes under various conditions; (iv) developing a dual functional sensing platform used for both Raman spectroscopy and fluorescence detection or both colorimetric and fluorescence; and (v) preparing a new nanomaterial that exhibits the ability of trace detection simultaneously and the removal of phenol and phenolic contaminants. Figure 12: (**A**) Schematic diagram of the fabrication process of uniformed MOF structures of Ag@MIL-101 (Fe)@MIPs. (**B**) (a) MOF-based Raman spectra at different concentrations of 2,6-DCP. (b) A linear curve of logarithmic 2,6-DCP concentration-correlated Raman intensities at 1575 cm\({}^{-1}\). Adapted from [42]. \begin{table}
\begin{tabular}{c c c c c} \hline \hline
**Plasmonic Structures** & **Detection Methods** & **Target Compounds** & **Limit of Detection** & **Reference** \\ \hline Au-modified tyrosinase-based GO & & & & \\ thin film & SPR & phenol & 1 \(\mu\)M & [9] \\ \hline Au@Ag nanorod dimers & Raman & dopamine & 0.006 pM & [11] \\ \hline  & & dopamine & 4.5 \(\mu\)g/mL & \\ DNA–copper hybrid nanoflowers & colorimetric & catechol & 3.0 \(\mu\)g/mL & [20] \\ \cline{2-5}  & & hydroquinone & 4.5 \(\mu\)g/mL & \\ \hline polyaniline/Pt-coated fiber optic & SPR & 4-nitrophenol & 0.34 pM & [23] \\ \hline GNPs\#TiO\({}_{2}\) & SPR & hydroquinone & 33.8 nM & [24] \\ \hline  & & vanillic acid & 10–250 \(\mu\)M & \\ \cline{2-5} SiO\({}_{2}\)/GNPs & Raman & syringic acid & 10–110 \(\mu\)M & [34] \\ \cline{2-5}  & & gallic acid & 5–55 \(\mu\)M & \\ \hline Cu\({}_{2}\)O@SiO\({}_{2}\)@ZIF-8@Ag & Raman & phenol red & 5.76 \(\times\) 10\({}^{-12}\) M & [36] \\ \hline Ag@MIL-101(Fe)@MIPs & Raman & 2,6-dichlorophenol & 4.5 nmol/L & [42] \\ \hline  & & catechol & 0.11 \(\mu\)M & [65] \\ \cline{2-5}  & & hydroquinone & 1.6 \(\mu\)M & \\ \hline Co-MOF-74-based Co\({}_{3}\)O\({}_{4}\)/cellulose & colorimetric & phenol & 1.02 \(\mu\)M & [69] \\ \hline Zr(IV)-based MOFs & colorimetric & phenol & 1.28 \(\mu\)M & [70] \\ \hline Adenosine monophosphate-Cu & UV/Vis & phenolic compounds & 0.033 \(\mu\)mol/L & [71] \\ \hline Au@Ni/rGO nanocomposite & colorimetric & phenol & 1.68 \(\mu\)M & [72] \\ \hline Fe\({}_{3}\)O\({}_{4}\)/rGO/MOF & colorimetric & phenol & 3.33 \(\times\) 10\({}^{-6}\) M & [73] \\ \hline AgNPs & fluorescence & dopamine & 5.3934 \(\times\) 10\({}^{-6}\) M & [80] \\ \hline Au-Ag nanocluster & fluorescence & dopamine & 6.9 nM & [84] \\ \hline Au nanoclusters & fluorescence & 4-nitrophenol & 13.8 nM & [85] \\ \hline chitosan/graphene quantum dots/Au & SPR & dopamine & 1.0 fM & [93] \\ thin film & SPR & dopamine & 0.23 \(\mu\)M & [96] \\ \hline carbon dot-functionalized GNPs & SPR & dopamine & 0.011 \(\mu\)g/cm\({}^{2}\) & [102] \\ \hline GNPs & Raman & methyl parathion & 21.5 \(\times\) 10\({}^{-9}\) M & [103] \\ \hline Ag-nanorod bundles & Raman & & 2,4-D & 61.9 \(\times\) 10\({}^{-9}\) M & [104] \\ \hline zipper-like ortho-Ag nanodimers & Raman & dopamine & 10 fM & [104] \\ \hline AgNPs-graphene based nanosheets & Raman & _p_-cresol & 10\({}^{-5}\) M & [105] \\ \hline SiO\({}_{2}\)/rGO/Au & Raman & 2,6-dichlorophenol & 100–1.0 nM & [106] \\ \hline Au-ZnO nanoparticle-modified & SPR & _p_-cresol & 57.43 \(\mu\)M & [107] \\ \hline ZnO/MoS\({}_{2}\) & SPR & _p_-cresol & 28 nM & [108] \\ \hline cetyltrimethylammonium-bromide-functionalized ZnO/carbon nanotube & plasmonic sensor & catechol & 0.1 \(\mu\)M & [109] \\ nanocomposite coated over Ag film & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 1: Comparison of plasmonic resonance-based optical sensors for on-site detection of phenolic compounds.