Extraction and high performance liquid chromatographic determination of 3-indole butyric acid in pea plants by using imidazolium-based ionic liquids as extractant

In this paper, imidazolium-based ionic liquids [C₄mim][PF₆], [C₆mim][PF₆], [C₈mim][PF₆], [C₆mim][BF₄] and [C₈mim][BF₄] were tested as extracting solvents for removal of 3-indole butyric acid (IBA) from aqueous media with subsequent determination using HPLC. Percent extraction of IBA was strongly affected by pH of aqueous phases and the chemical structures of ionic liquids (ILs). Extraction of IBA was quantitative in the pH values lower than pK_a of IBA. Considering both extraction and stripping efficiencies of IBA, [C₄mim][PF₆] was found to act more efficient than other studied ILs. Capacity of [C₄mim][PF₆] was 17.6 × 10⁻⁴ mmol IBA per 1.0 mL of IL. Ionic strength of aqueous phase and temperature had shown no serious effects on extraction efficiency of IBA. A preconcentration factor of 100 and a relative standard deviation of 1.16% were obtained. It was found that ionic liquid phase was reusable almost five times for extraction/stripping purposes. 3-Indole acetic acid showed interferential effect in the extraction step. In order to assess the applicability of the method, extraction and stripping of IBA from pea plants and some other samples were studied.     

Room temperature ionic liquid as a novel medium for liquid/liquid extraction of metal ions

Room temperature ionic liquids (RTILs) have been used as novel solvents to replace traditional volatile organic solvents in organic synthesis, solvent extraction, and electrochemistry. The hydrophobic character and water immiscibility of certain ionic liquids allow their use in solvent extraction of hydrophobic compounds. In this work, a typical room temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate [C₄mim][PF₆], was used as an alternative solvent to study liquid/liquid extraction of heavy metal ions. Dithizone was employed as a metal chelator to form neutral metal-dithizone complexes with heavy metal ions to extract metal ions from aqueous solution into [C₄mim][PF₆]. This extraction is possible due to the high distribution ratios of the metal complexes between [C₄mim][PF₆] and aqueous phase. Since the distribution ratios of metal dithiozonates between [C₄mim][PF₆] and aqueous phase are strongly pH dependent, the extraction efficiencies of metal complexes can be manipulated by tailoring the pH value of the extraction system. Hence, the extraction, separation, and preconcentraction of heavy metal ions with the biphasic system of [C₄mim][PF₆] and aqueous phase can be achieved by controlling the pH value of the extraction system. Preliminary results indicate that the use of [C₄mim][PF₆] as an alternate solvent to replace traditional organic solvents in liquid/liquid extraction of heavy metal ions is very promising.     

Homogeneous ionic liquid microextraction of the active constituents from fruits of Schisandra chinensis and Schisandra sphenanthera

Homogeneous ionic liquid microextraction (HILME) was developed for the extraction of schizandrin, schisantherin A and deoxyschizandrin from Schisandra chinensis and Schisandra sphenanthera. 1-Butyl-3-methylimidazolium tetrafluoroborate ([C₄MIM][BF₄]) aqueous solution was used as extraction solvent, and ammonium hexafluorophosphate ([NH₄][PF₆]) was used as ion-pairing agent. 1-Butyl-3-methylimidazolium hexafluorophosphate ([C₄MIM][PF₆]), which is barely soluble in water, was formed in situ, and was used as sample solution. High-performance liquid chromatography (HPLC) was employed for separation and determination of the analytes. The calibration curve showed good linear relationship (r > 0.9998). The recoveries were between 69.71% and 88.33% with RSDs lower than 4.86%. External standard method was adopted in the proposed method, and internal standard method was applied for the evaluation of the proposed method. The two methods were compared and the results indicated that the proposed method was acceptable and simple. The HILME is free of volatile organic solvents, and represents lower expenditures of sample, extraction time and solvent, compared with ultrasonic and Soxhlet extraction. There was no obvious difference in the extraction yields of active constitutions obtained by the three extraction methods.     

Determination of triazines in honey by dispersive liquid–liquid microextraction high-performance liquid chromatography

Dispersive liquid–liquid microextraction (DLLME) high-performance liquid chromatography (HPLC) was developed for extraction and determination of triazines from honey. A room temperature ionic liquid, 1-hexyl-3-methylimidazolium hexafluorophosphate [C₆MIM][PF_6.], was used as extraction solvent and Triton X 114 was used as dispersant. A mixture of 175 μL [C₆MIM][PF₆] and 50 μL 10% Triton X 114 was rapidly injected into the 20 mL honey sample by syringe. After extraction, phase separation was performed by centrifugation and the sedimented phase was analyzed by HPLC. Some experimental parameters, such as type and volume of extraction solvent, concentration of dispersant, pH value of sample solution, salt concentration and extraction time were investigated and optimized. The detection limits for chlortoluron, prometon, propazine, linuron and prebane are 6.92, 5.84, 8.55, 8.59 and 5.31 μg kg⁻¹, respectively. The main advantages of the proposed method are simplicity of operation, low cost, high enrichment factor and extraction solvent volume at microliter level. Honey samples were analyzed by the proposed method and obtained results indicated that the proposed method provides acceptable recoveries and precisions.     

1-Butyl-2,3-trimethyleneimidazolium bis(trifluoromethylsulfonyl)imide ([b-3C-im][NTf2]): a new, stable ionic liquid

Using imidazole as the starting material, the synthesis of a new bicyclic ionic liquid [b-3C-im][NTf₂] is described. Except for the alkylation reaction in the second step (40% yield) of this four-step synthesis of [b-3C-im][NTf₂], others were all high yielding reactions (85-94% isolated yields). We investigated intrinsic reactivity of this and other imidazolium-based ionic liquids and found that, under strongly basic conditions (KOD in CD₃OD/D₂O (1:1) solution), the new ionic liquid was stable to solvent deuterium isotope exchange while the previously reported [bdmim][NTf₂] and [bdmim][PF₆] ionic liquids were 50% deuterium exchanged at its C-2 methyl in 30 min at ambient temperature. At the same experimental condition, the most commonly employed [bmim][PF₆] ionic liquid was deuterium exchanged instantaneously at its C-2 hydrogen. In the absence of bases (CD₃OD/D₂O = 1:1), only [bmim][PF₆] was deuterium exchanged (50% within 1 h) and other ionic liquids gave no detectable exchanges even after one week at ambient temperature. It is therefore concluded that the new [b-3C-im][NTf₂] ionic liquid is far more chemically stable than previously reported [bmim][PF₆], [bdmim][NTf₂], and [bdmim][PF₆].     

Speciation of mercury by ionic liquid-based single-drop microextraction combined with high-performance liquid chromatography-photodiode array detection

Room temperature ionic liquids can be considered as environmentally benign solvents with unique physicochemical properties. Ionic liquids can be used as extractant phases in SDME, being compatible with chromatographic systems. A single-drop microextraction method was developed for separation and preconcentration of mercury species (MeHg⁺, EtHg⁺, PhHg⁺ and Hg²⁺), which relies on the formation of the corresponding dithizonates and microextraction of these neutral chelates onto a microdrop of an ionic liquid. Afterwards, the separation and determination were carried out by high-performance liquid chromatography with a photodiode array detector. Variables affecting the formation and extraction of mercury dithizonates were optimized. The optimum conditions found were: microextraction time, 20 min; stirring rate, 900 rpm; pH, 11; ionic liquid type, 1-hexyl-3-methylimidazolium hexafluorophosphate ([C₆MIM][PF₆]); drop volume, 4 μL; and no sodium chloride addition. Limits of detection were between 1.0 and 22.8 μg L⁻¹ for the four species of mercury, while the repeatability of the method, expressed as relative standard deviation, was between 3.7 and 11.6% (n = 8). The method was finally applied to the determination of mercury species in different water samples.     

Ultrasound-assisted ionic liquid dispersive liquid-phase micro-extraction: A novel approach for the sensitive determination of aromatic amines in water samples

Ultrasound-assisted ionic liquid dispersive liquid-phase micro-extraction was developed for the determination of four aromatic amines such as 2,4-dichloroaniline, 1-naphthylamine, 6-chloroanline and N,N-dimethylaniline. High-performance liquid chromatography coupled with UV detector was used for the determination of aromatic amines. In the novel procedure, 1-hexyl-3-methylimidazolium hexafluorophosphate [C₆MIM] [PF₆] was dispersed into the aqueous sample solution as fine droplets by ultrasonication, and which promoted the analytes more easily migrate into the ionic liquid phase. Variable affecting such as the volume of [C₆MIM] [PF₆], sample pH, ultrasonication time, extraction time, centrifuging time have been investigated in detail. The proposed method has been found to have excellent detection sensitivity with limits of detection (LOD, S/N = 3) in the range of 0.17–0.49 μg L⁻¹ and precisions in the range of 2.0–6.1% (RSDs, n = 6). This method has been also successfully applied to analyze the real water samples and good spiked recoveries over the range of 92.2–119.3% were obtained.     

Determination of bisphenol A, 4-n-nonylphenol, and 4-tert-octylphenol by temperature-controlled ionic liquid dispersive liquid-phase microextraction combined with high performance liquid chromatography-fluorescence detector

Present study described a simple, sensitive, and viable method for the determination of bisphenol A, 4-n-nonylphenol and 4-tert-octylphenol in water samples using temperature-controlled ionic liquid dispersive liquid-phase microextraction coupled to high performance liquid chromatography-fluorescence detector. In this experiment, 1-octyl-3-methylimidazolium hexafluorophosphate ([C₈MIM][PF₆]) was used as the extraction solvent, and bisphenol A, 4-n-nonylphenol and 4-tert-octylphenol were selected as the model analytes. Parameters affecting the extraction efficiency such as the volume of [C₈MIM][PF₆], dissolving temperature, extraction time, sample pH, centrifuging time and salting-out effect have been investigated in detail. Under the optimized conditions, good linear relationship was found in the concentration range of 1.0-100 μg L⁻¹ for BPA, 1.5-150 μg L⁻¹ for 4-NP, and 3-300 μg L⁻¹ for 4-OP, respectively. Limits of detection (LOD, S/N = 3) were in the range of 0.23-0.48 μg L⁻¹. Intra day and inter day precisions (RSDs, n = 6) were in the range of 4.6-5.5% and 8.5-13.3%, respectively. This method has been also successfully applied to analyze the real water samples at two different spiked concentrations and excellent results were obtained.     

Solvent (ionic liquid) impregnated resin-based extraction coupled with dynamic ultrasonic desorption for separation and concentration of four herbicides in environmental water

A new method was developed for the determination of monolinuron, propazine, linuron, and prebane in environmental water samples. The solvent (ionic liquid) impregnated resin (IL-SIR)-based extraction coupled with dynamic ultrasonic desorption (DUSD) was applied to the separation and concentration of the analytes. The high performance liquid chromatography (HPLC) was applied to the determination of the analytes. The ionic liquid [C₆MIM][PF₆] was immobilized on Diaion HP20 resin by immersing the resin in ethanol solution containing [C₆MIM][PF₆]. The effect of extraction parameters, including pH value of sample solution, salt concentration in sample and extraction time, and elution conditions, including the concentration of ethanol in elution solvent, the flow rate of elution solvent and the ultrasonic power, were examined and optimized. The limits of detection and quantification for the analytes were in the range of 0.15-0.29 μg L⁻¹ and 0.51-0.98 μg L⁻¹, respectively. Some environmental water samples were analyzed and the analytical results were satisfactory.     

Determination of Triazines by Ultrasonic-Assisted Ionic Liquid Microextraction Coupled with High Performance Liquid Chromatography

The determination of triazine herbicides by ultrasonic‐assisted ionic liquid microextraction coupled with high‐performance liquid chromatography was described. 1‐Hexyl‐3‐methylimidazolium hexafluorophosphate ([C₆MIm][PF₆]) was used as the extraction solvent and some extraction parameters, including volume of [C₆MIm][PF₆], extraction temperature and time, salt concentration and pH values of sample solution, were examined and optimized. The isolation of the target compounds from the matrix was found to be efficient when triazines in 10 mL of sample solution was extracted with 100 µL of [C₆MIm][PF₆] for 40 min at 50°C. The detection limits for the triazine range from 0.36 to 1.41 µg·L^?1. The satisfactory recoveries (82.3% –120.3%) with relative standard deviations ≦10.1% were obtained for the four triazine herbicides from six kinds of practical water samples.     

Preconcentration of aqueous dyes through phase-transfer liquid-phase microextraction with a room-temperature ionic liquid

In this study, we employed the room-temperature ionic liquid [bmim][PF₆] as both ion-pair agent and an extractant in the phase-transfer liquid-phase microextraction (PTLPME) of aqueous dyes. In the PTLPME method, a dye solution was added to the extraction solution, comprising a small amount of [bmim][PF₆] in a relatively large amount of CH₂Cl₂, which serves as the disperser solvent to an extraction solution. Following extraction, CH₂Cl₂ was evaporated from the extractant, resulting in the extracted dyes being concentrated in a small volume of the ionic liquid phase to increase the enrichment factor. The enrichment factors of for the dye Methylene Blue, Neutral Red, and Methyl Red were approximately 500, 550 and 400, respectively; their detection limits were 0.014, 0.43, and 0.02 μg L⁻¹, respectively, with relative standard deviations of 4.72%, 4.20%, and 6.10%, respectively.     

Evaluation and comparison of global scalar properties for the simultaneous interaction of ionic liquids with thiophene and pyridine

Ab initio studies were carried out with mixtures containing ionic liquid with thiophene and pyridine for studying the simultaneous interaction. Global scalar properties such as HOMO/LUMO energies, HOMO–LUMO energy gap, chemical hardness, chemical potential, electronegativity, global hardness, global softness and electrophilicity index were determined for clusters containing ionic liquids with thiophene and pyridine. Ionic liquids containing: 1-butyl-3-methylpyrrolidinium [BUMPYR], 1-benzyl-3-methyimidazolioum [BeMIM] and 1-butyl-3-methylpyridinium [BUMPY] cations combined with inorganic anions containing fluorine ([BF₄] and [PF₆]) were studied in this work. [BeMIM][BF₄] (1-benzyl-3-methyimidazolioum tetrafluoroborate) with a HOMO–LUMO energy gap of 0.1882 Hartrees was found to be the most effective IL. Further a ranking based on all the mentioned scalar parameters also pointed out [BeMIM][BF₄] to be the most desirable IL. The overall ranking after taking into considerations all factors followed: [BeMIM][BF₄] > [BUMPYR][BF₄] > [BUMPY][PF₆] > [BUMPY][BF₄] > [BUMPYR][PF₆]. To validate the findings, infinite dilution activity coefficients were predicted using the quantum chemical based COSMO-RS methodology which gave the same trend as observed using scalar properties.     

A Novel Room Temperature Ionic Liquid Extraction Spectrophotometric Determination of Trace Germanium in Natural Water with Methybenzeneazosalicylfluorone

Abstract

This paper describes a highly sensitive and selective extraction spectrophotometric method for determination of trace germanium in natural water with new a chromogenic reagent methybenzeneazosalicylfluorone abbreviated as MBASF, in which a typical room temperature ionic liquid, 1‐butyl‐3‐methylimidazolium hexafluorophosphate abbreviated as [C₄mim][PF₆] was used as novel medium for liquid/liquid extraction of germanium(IV). In the presence of TritonX‐100, MBASF reacted with germanium(IV) to form a red complex rapidly, the complex was then extracted into the [C₄mim][PF₆] phase, the absorbance of the complex in ionic liquid at 496 nm was recorded and used to determine trace germanium(IV). The apparent molar absorptivity of the complex and the detection limit for the real sample were found to be 3.12×10⁶ L mol^?1 cm^?1 and 0.2 ng mL^?1, respectively. The absorbance of the complex at 496 nm increases linearly with the concentration up to 4 µg of germanium (IV) in 250 mL of aqueous solution. The interference study show the determination of germanium is free from the interference of almost all positive and negative ions found in the natural water samples. The determination of germanium in natural water was carried out by the present method and electrothermal atomic absorption spectrometry (AAS). The results were satisfactorily comparable so that the applicability of the proposed method was confirmed using the real samples. Moreover, the extraction mechanism with the ionic liquid system was also investigated. We think the extraction performance of the ionic liquid system is a combination of ion‐pairing effect between imidazolium cation and basic solute in the aqueous phase with the dissolution of polar molecule in ionic liquid phase. A wise choice of the appropriate combination of anion with imidazolium cation hydrophobicity allows playing with solute selectivity.     

Ultrasonication-assisted extraction and preconcentration of medicinal products from herb by ionic liquids

Ionic liquid-based extraction of medicinal or useful compounds from plants was investigated as an alternative to supercritical fluid, cloud point and conventional organic solvent extractions. The method integrated extraction and preconcentration. Medicinal products were first extracted by an ionic liquid solution, part of which was then converted to a hydrophobic form by anion metathesis for preconcentration. The remaining soluble ionic liquid acted as a dispersive agent to enhance the efficiency of preconcentration. Protein in the extract was precipitated spontaneously without addition of further solvents. Ultrasonication assisted this method for extraction and preconcentration of cryptotanshinone, tanshinone I and tanshinone II A from Salvia Miltiorrhiza Bunge. 0.233 mg g⁻¹, 0.695 mg g⁻¹ and 0.682 mg g⁻¹ of each, respectively, were extracted using [OMIM][Cl], and preconcentrated in a [OMIM][PF₆] phase at respective concentrations of 148.1, 507.1 and 486.1 μg mL⁻¹. The method exhibited potential applicability with other medicinal products.     

Ionic liquids extraction of Para Red and Sudan dyes from chilli powder, chilli oil and food additive combined with high performance liquid chromatography

A simple analytical method, based on the coupling of ionic liquid-based extraction with high performance liquid chromatography (HPLC), is developed for the determination of Sudan dyes (I, II, III and IV) and Para Red in chilli powder, chilli oil and food additive samples. Two ionic liquids (ILs), 1-butyl-3-methylimidazolium hexafluorophosphate ([C₄mim][PF₆]) and 1-octyl-3-methylimidazolium hexafluorophosphate ([C₈mim][PF₆]), were compared as extraction solvents; experiments indicated that the latter possesses higher recoveries for each analyte. Parameters related to extraction of Sudan dyes and Para Red were also optimized. Under the optimal conditions, good reproducibility of extraction performance was obtained, with the relative standard deviation (RSD) values ranging from 2.0% to 3.5%. The detection limits of Sudan dyes and Para Red (LOD, S/N = 3) were in the range of 7.0-8.2 μg kg⁻¹ for chilli powder and 11.2-13.2 μg L⁻¹ for chilli oil and food additive. The recoveries were in the range of 76.8-109.5% for chilli powder samples and 70.7-107.8% for chilli oil and food additive samples.     

Hollow fiber supported ionic liquid membrane microextraction for determination of sulfonamides in environmental water samples by high-performance liquid chromatography

By using ionic liquid as membrane liquid and tri-n-octylphosphine oxide (TOPO) as additive, hollow fiber supported liquid phase microextraction (HF-LPME) was developed for the determination of five sulfonamides in environmental water samples by high-performance liquid chromatography with ultraviolet detection The extraction solvent and the parameters affecting the extraction enrichment factor such as the type and amount of carrier, pH and volume ratio of donor phase and acceptor phase, extraction time, salt-out effect and matrix effect were optimized. Under the optimal extraction conditions (organic liquid membrane phase: [C₈MIM][PF₆] with 14% TOPO (w/v); donor phase: 4 mL, pH 4.5 KH₂PO₄ with 2 M Na₂SO₄; acceptor phase: 25 μL, pH 13 NaOH; extraction time: 8 h), low detection limits (0.1–0.4 μg/L, RSD ≤ 5%) and good linear range (1–2000 ng/mL, R² ≥ 0.999) were obtained for all the analytes. The presence of humic acid (0–25 mg/L dissolved organic carbon) and bovine serum albumin (0–100 μg/mL) had no significant effect on the extraction efficiency. Good spike recoveries over the range of 82.2–103.2% were obtained when applying the proposed method on five real environmental water samples. These results indicated that this present method was very sensitive and reliable with good repeatabilities and excellent clean-up in water samples. The proposed method confirmed hollow fiber supported ionic liquid membrane based LPME to be robust to monitoring trace levels of sulfadiazine, sulfamerazine, sulfamethazine, sulfadimethoxine and sulfamethoxazole in aqueous samples.     

Determination of phenylurea and triazine herbicides in milk by microwave assisted ionic liquid microextraction high-performance liquid chromatography

The determination of phenylurea and triazine herbicides in milk based on microwave assisted ionic liquid microextraction (MAILME) coupled with high-performance liquid chromatographic separation was described. The experimental parameters of the MAILE, including type and amount of ionic liquid, microwave extraction power, extraction time and salt concentration in sample, were evaluated by a univariate method and orthogonal screening. When 60 μL of [C₆MIM][PF₆] was used as extraction solvent the target compounds can be isolated from the 4 mL of milk. The MAILME is quick (7 min) and simple. The detection limits for isoproturon, monolinuron, linuron, propazine, prometryne, terbutryn and trietazine are 0.46, 0.78, 1.00, 1.21, 1.96, 0.84 and 1.28 μg L⁻¹, respectively. The proposed method was applied to the analysis of milk samples and the recoveries of the analytes ranged from 88.4 to 117.9% and relative standard deviations were lower than7.43%.     

Ionic liquid-based single drop microextraction combined with electrothermal atomic absorption spectrometry for the determination of manganese in water samples

Room temperature ionic liquid, 1-butyl-3-methylimidazolium hexafluorophosphate [C₄MIM][PF₆], was used as an alternative to volatile organic solvents in single drop microextraction-electrothermal atomic absorption spectrometry (SDME-ETAAS). Manganese was extracted from aqueous solution into a drop of the ionic liquid after complextaion with 1-(2-thiazolylazo)-2-naphthol (TAN) and the drop was directly injected into the graphite furnace. Several variables affecting microextraction efficiency and ETAAS signal, such as pyrolysis and atomization temperature, pH, TAN concentration, extraction time, drop volume and stirring rate were investigated and optimized. In the optimum experimental conditions, the limit of detection (3 s) and the enhancement factor were 0.024 μg L⁻¹ and 30.3, respectively. The relative standard deviation (RSD) for five replicate determinations of 0.5 μg L⁻¹ Mn(II) was 5.5%. The developed method was validated by the analysis of a certified reference material (NIST SRM 1643e) and applied successfully to the determination of manganese in several natural water samples.     

Cold-induced aggregation microextraction: a novel sample preparation technique based on ionic liquids

In this research, a novel microextraction technique based on ionic liquids (ILs) termed cold-induced aggregation microextraction (CIAME) is developed. In this method, very small amounts of 1-hexyl-3-methylimidazolium hexafluorophosphate [Hmim][PF₆] and 1-hexyl-3-methylimidazolium bis (trifluoromethylsulfonyl) imide [Hmim][Tf₂N] (as extractant solvents) were dissolved in a sample solution containing Triton X-114 (as an anti-sticking agent). Afterwards, the solution was cooled in the ice bath and a cloudy solution was formed. After centrifuging, the fine droplets of extractant phase were settled to the bottom of the conical-bottom glass centrifuge tube.CIAME is a simple and rapid method for extraction and preconcentration of metal ions from water samples and can be applied for the sample solutions containing high concentration of salt and water miscible organic solvents. Furthermore, this technique is much safer in comparison with the organic solvent extraction.Performance of the technique was evaluated by determination of the trace amounts of mercury as a test analyte in several real water samples. Michler thioketone (TMK) was chosen as a complexing agent. Analysis was carried out using spectrophotometric detection method. Type and amount of IL and the surfactant, temperature and the other parameters were optimized. Under the optimum conditions, the limit of detection (LOD) of the method was 0.3 ng mL⁻¹ and the relative standard deviation (R.S.D.) was 1.32% for 30 ng mL⁻¹ mercury.     

Solubilities of imidazolium-based ionic liquids in aqueous salt solutions at 298.15 K

The solubilities of ionic liquids in the ternary systems (ionic liquid + H₂O + inorganic salt) were reported at 298.15 K and atmospheric pressure. The examined ionic liquids are [C₄mim][PF₆] (1-n-butyl-3-methylimidazolium hexafluorophosphate), [C₈mim][PF₆] (1-n-octyl-3-methylimidazolium hexafluorophosphate), and [C₈mim][BF₄] (1-n-octyl-3-methylimidazolium tetrafluoroborate). The examined inorganic salts are the chloride-based salts (sodium chloride, lithium chloride, potassium chloride, and magnesium chloride) and the sodium-based salts (sodium thiocyanate, sodium nitrate, sodium trifluoroacetate, sodium bromide, sodium iodide, sodium perchlorate, sodium acetate, sodium hydroxide, sodium dihydrogen phosphate, sodium phosphate, sodium tetrafluoroborate, sodium sulfate, and sodium carbonate). The effects of the cations and the anions of the ionic liquids and of the inorganic salts on the solubility of the ionic liquids in the ternary solutions were systematically compared and discussed.