## 3 Ionic Liquids (ILs) as Green Extraction Phase
### Magnetic Ionic Liquids (MILs) as Green Extraction Phase
\begin{table}
\begin{tabular}{c c c c c c c c} \hline \hline
**Method** & **MIL** & **Analyte** & **Matrix** & **LOD** & **Instrumentation** & **Ref.** \\ \hline In situ DLLME & [P\({}_{6,6,61^{+}}\)]2[CoCl4\({}^{2-}\)] & Biogenic amines & Wine fish & 1.3–3.9 \(\mathrm{\SIUnitSymbolMicro}\) L\({}^{-1}\) & HPLC-UV & [47] \\ \hline \multirow{6}{*}{DLLME} & \multirow{6}{*}{[P\({}_{6,6,61^{+}}\)]2[CoCl4\({}^{2-}\)]} & Estrieol & & & & \\  & & Estrone & & & & \\ \cline{1-1} \cline{3-6}  & & Parabens Carbamazepine & & & & \\ \cline{1-1} \cline{3-6}  & & Diacepan & & & & \\ \cline{1-1} \cline{3-6}  & & Ketropfer & & & & \\ \cline{1-1} \cline{3-6}  & & Ibuprofen & & & & \\ \cline{1-1} \cline{3-6}  & & 17\(\mathrm{\SIUnitSymbolMicro}\)-Ethynylestradiol & River water & 1.5–15 \(\mathrm{\SIUnitSymbolMicro}\) L\({}^{-1}\) & HPLC-DAD & [48] \\ \cline{1-1} \cline{3-6}  & & & Aldicarb & & & \\ \cline{1-1} \cline{3-6}  & & Methyl parathion & & & & \\ \cline{1-1} \cline{3-6}  & & Metolachlor & & & & \\ \cline{1-1} \cline{3-6}  & & Diuron & & & & \\ \cline{1-1} \cline{3-6}  & & Bisphenol A & & & & \\ \hline \hline \end{tabular}
\end{table} 
Table 2: Recent applications of magnetic ionic liquids (MILs) for extraction of different analytes from various matrices. DLLME—liquid–liquid dispersive microextraction. Deep Eutectic Solvent (DES) and Natural Deep Eutectic Solvents (NADES) as a Green Extraction Solvent  
The concept of deep eutectic solvents (DESs) was first introduced by [PERSON] et al. in 2003 [PERSON] et al. (2003). DESs consist of two solid compounds interacting via hydrogen bonds to form a liquid phase with a lower melting point compared to each individual component [PERSON] et al. (2003). The most popular DES involves the combination of choline chloride (ChCl) with urea, carboxylic acids (e.g., citric, succinic, and oxalic acids) and glycerol acting as hydrogen bond donors (HBDs). The use of ChCl has been related to some advantages for DES production, including ease of preparation, biocompatibility, non-toxicity and biodegradability. Although DESs are considered a subclass of IL, they are cheaper and easier to prepare due to the lower cost of the raw materials. Also, they present less toxicity and are often biodegradable, which makes them valuable alternative solvents. One of the most attractive features of these solvents is that, like ILs, their chemical properties can be tuned through the manipulation of their chemical structures (HBA and HBD) to interact more effectively with the target analytes. [PERSON] et al. (2018) [PERSON] et al. (2018) provide a closer look into DES intermolecular interactions; however, there is still a lack of knowledge regarding this topic. In 2017, [PERSON] et al. published a review of the applications of DES in analytical chemistry, including their use in the extraction phase in microextraction techniques [PERSON] et al. (2017). Nowadays, these solvents represent a very promising alternative in the sample preparation area, mainly due to their easy  
\begin{table}
\begin{tabular}{c c c c c c c} \hline \hline  
Figure 3: An overview of the extraction procedure using the novel parallel-single-drop microextraction (Pa-SDME)/MIL-based approach. Reproduced with permission from ([PERSON] et al., 2017). acquisition and versatility for extract different classes of compounds. In the work of [PERSON] et al., a gas-assisted DLLME method using a mixture of ChCl and 4-chlorophenylenol (1:2 molar ratio) as the extraction solvent was developed for pesticide residue determination in vegetable and fruit by GC-FID [60]. The proposed method was optimized, and enrichment factors and extraction recoveries were achieved in the range of 247-355 and 49-71%, respectively. Two hydrophobic deep eutectic solvents were synthetized and used as the extraction solvent with air-assisted DLLME (AA-DLLME) for pre-concentration and extraction of benzophenone-type UV filters from aqueous samples and determination by HPLC-DAD [61]. DESs were obtained by mixing DL-menthol and quaternary ammonium salts with a straight-chain monobasic acid.