Title Page
Abstract
국문요약
Contents
Chapter 1. Overview of deep eutectic solvents 21
1.1. Definition and preparation of deep eutectic solvents 21
1.2. Classification of deep eutectic solvents 23
1.3. Physicochemical properties of DES on the extraction process 24
1.3.1. Melting point 25
1.3.2. Density 26
1.3.3. Viscosity 27
1.3.4. Polarity 28
1.4. Limitations and challenges 29
1.5. Propose of this work 31
Chapter 2. Determination of thiophanate-methyl and carbendazim from environmental water by liquid-liquid microextraction using hydrophobic deep eutectic solvents 33
2.1. Introduction 33
2.1.1. Thiophanate-methyl and carbendazim 33
2.1.2. Hydrophilic DESs 34
2.1.3. Liquid-liquid microextraction (LLME) technology 34
2.2. Experimental 35
2.2.1. Instruments 35
2.2.2. Reagents and materials 36
2.2.3. Chromatographic conditions 36
2.2.4. Preparation of hydrophobic DESs 37
2.2.5. Procedure of Vortex-assisted LLME 38
2.3. Results and discussion 39
2.3.1. Characterization of DESs 39
2.3.2. Selection of hydrophobic DESs for LLME 41
2.3.3. Optimization of the extraction process 43
2.3.4. Selective extraction of different pesticides with hydrophobic DES 47
2.3.5. Comparison of the hydrophobic DES and halogenated solvents as extractants 48
2.3.6. Method validation 50
2.3.7. Application of real sample 51
2.3.8. Comparison of vortex-assisted LLME with other methods 52
Chapter 3. Utilization of ionic deep eutectic solvent as sustainable mobile phase additive in HPLC for improving the separation of biogenic amines 54
3.1. Introduction 54
3.1.1. Biogenic amines (BAs) 54
3.1.2. Determination methods of BAs 55
3.1.3. DESs as mobile phase additives 56
3.2. Experimental 57
3.2.1. Reagents and Materials 57
3.2.2. Apparatus and conditions for chromatography 57
3.2.3. Preparation of DESs 58
3.2.4. Cooking wine sample preparation 59
3.3. Results and Discussion 59
3.3.1. Effect of different mobile phase additives 59
3.3.2. Effect of difference DES types 61
3.3.3. Response surface methodology (RSM) 62
3.3.4. Method validation 67
3.3.5. Analysis of real samples 68
Chapter 4. Deep eutectic solvents based in situ isolation technique for extractive deterpenation of essential oils 70
4.1. Introduction 70
4.1.1. Essential oils 70
4.1.2. Deterpenation technology of essential oils 71
4.2. Experimental 73
4.2.1. Reagents and chemicals 73
4.2.2. Extraction process 74
4.2.3. Analysis methods 76
4.2.4. Theoretical calculation 77
4.3. Results and discussion 79
4.3.1. Modeling and evaluation using COSMO-RS methodology 79
4.3.2. Analysis of DFT calculation results 85
4.3.3. Experimental determination of terpenoids extraction 88
4.3.4. Optimization of the molar ratio of organic salt 91
4.3.5. Purification of crude DES 94
4.3.6. Re-extraction of terpenoids from terpeneless DES 97
Conclusions 100
Reference 104
Appendix 138
List of publications 148
Table 1. Composition of the 12 kinds of hydrophobic DESs. 37
Table 2. Analytical characteristics of the hydrophobic DES-based LLME for the targets. 51
Table 3. Comparison with other works for the determination of TM and CA. 53
Table 4. Composition and molar ratio of DESs. 59
Table 5. Independent variables and levels for BBD. 62
Table 6. Statistical results of quadratic regression model obtained from ANOVA. 65
Table 7. Interaction energies and hydrogen bond length of different complexes. 87
Fig. 1. HBA and HBD components of the DES used for extraction. 22
Fig. 2. General formula for four types of DES. 24
Fig. 3. Schematic diagram of the vortex-assisted LLME procedure. 39
Fig. 4. FT-IR spectra of DES-1, thymol and hexanoic acid. 40
Fig. 5. Stability of hydrophobic DESs (DES-1~DES-12, upper layer) in water (bottom layer) for one week. 41
Fig. 6. Effects of 12 different kinds of hydrophobic DES on the extraction efficiency of TM and CA. 42
Fig. 7. Influence of different factors on the extraction efficiency during the extraction process. (a) Four assisting methods; (b) different molar ratios of... 44
Fig. 8. (a) Extraction efficiency of hydrophobic DES for thiophanate-methyl (TM), carbendazim (CA), chlorpyrifos (CPs) and parathion-methyl (PM); (b)... 49
Fig. 9. Phase position of DES-11 (upper layer) and chlorinated organic solvents (bottom) in water solution. 50
Fig. 10. Chromatograms of TM and CA detected in real samples base on LLME. 52
Fig. 11. (A) HPLC chromatograms of eight BAs with different mobile phase additives: (a) without additive, (b) ammonium acetate,... 61
Fig. 12. 3D desirability surface plots generated when simultaneously optimizing the following pair of key independent variables: (A) DES... 67
Fig. 13. HPLC chromatogram of biogenic amines in cooking wine sample contains a built-in table of detected biogenic amines with concentrations. 69
Fig. 14. Schematic diagram of extractive deterpenation of essential oils. 74
Fig. 15. σ-Profiles of hydroxy-terpenoids, keto-terpenoids, and terpenes. 81
Fig. 16. σ-Profiles of organic salts. 82
Fig. 17. COSMO-RS interactions between terpenoids/terpenes and (A) TBAC, (B) DTMAB, (C) ChCl, (D) TMAC, and (E) TBAB. 84
Fig. 18. ESP maps of terpenoids, terpenes and organic salts. 86
Fig. 19. (A) Recovery of TBAC for different terpenoids and terpenes; (B) FT-IR spectra of linalool-based DES and related compounds; (C)... 91
Fig. 20. (A) COSMO-RS interactions between different molar ratios of TBAC to linalool; (B) σ-Profiles of the DES composed of different... 92
Fig. 21. (A) COSMO-RS interactions between limonene and organic solvents ((1) ethylacetate; (2) acetonitrile; (3) toluene; (4) methanol;... 95
Fig. 22. Extraction performance of different mass ratios of (A) water and DES (ratio of n-hexane/DES is fixed to 1.0); (B) n-hexane and... 98
Fig. 23. Extraction efficiency of recycled TBAC. 99