Deep Eutectic Solvent-based Liquid-phase Research Articles

Development of liquid phase microextraction-based deep eutectic solvent for the extraction and determination of toxic metal ions in herbal medicines

Herein, an eco-friendly, simple, and inexpensive procedure was developed using vortex-assisted combined with deep eutectic solvent-based liquid phase microextraction (VA-LPME-DES) followed by graphite furnace atomic absorption spectrometry. In the present procedure, DES was first synthesized from the combination of l-menthol and (1S)-(+)-camphor-10-sulfonic acid (CSA) in a molar ratio of 5:1, and then it was used as a green and safe extractant instead of common toxic organic solvents. The ability of the presented method was applied for the separation and preconcentration of lead (Pb), cadmium (Cd), mercury (Hg), and arsenic (As) in herbal medicines. After optimizing all the parameters of the experiment, the linear ranges were 0.10–200 µg kg−1 with coefficient of determination (r 2) better than 0.985. The limits of detection were in the ranges of 0.03–0.15 µg kg−1. Relative standard deviation values for intra-day and inter-day of the method based on 7 replicate measurements were in the range of 1.8%–3.6% and 3.1%–7.3%, respectively. The relative recoveries of herbal medicines which have been spiked with different concentrations of metal ions were 91.5%–109.8%. The method was successfully used to analyze the heavy and toxic metals in herbal medicine samples.

An effervescence-assisted switchable deep eutectic solvent based liquid-phase microextraction of triazole fungicides in drinking water and beverage

A new effervescence-assisted switchable deep eutectic solvent-based liquid phase microextraction (EA-SDES-LPME) combined with HPLC-UV was developed for determination of common triazole fungicides in drinking water and beverages, including myclobutanil, flusilazole, hexaconazole and bitertanol. The alternative extraction solvent was prepared with hexafluoroisopropanol and dipropylamine with the merits of time-saving, easy to collect and cost-effectiveness. The SDES can be reversibly switched between hydrophilic and hydrophobic states by pH adjustment. The homogeneous extraction was achieved under the hydrophilic form of SDES, and the bi-phase separation was obtained easily by adjusting pH value to restore the original hydrophobicity. Moreover, the characterization of SDES was investigated by FTIR and 1H NMR. The main variables affecting extraction efficiency were optimized in detail. Under the optimal conditions, the proposed method shows desirable precision (RSDs less than 18.5%) and acceptable recovery (72.6–95.4%). The lower limits of detection and limits of quantitation were found to be in the range of 1–2 μg L-1 and 5–10 μg L-1, respectively. The formation mechanism of SDES and the extraction mechanism for target analytes were investigated by density functional theory. The proposed methodology was simplicity, sensitive, time-saving and successfully applied to determine triazole fungicides in drinking water and beverages, making it an alternative technique for the analysis of trace analytes with satisfactory sensitivity.

Development and Factorial Experimental Design Optimization of Deep Eutectic Solvent‐Based Microextraction of Carmoisine (E122) in Candy and Water Samples

A new deep eutectic solvent-based liquid phase microextraction (DES-LPME) method was developed and used to separate and enrich Carmoisine (E122). The deep eutectic solvent containing tetrabutylammonium bromide (TBABr) and decanoic acid (DA) was prepared and employed with multivariate statistical design for the optimization of the spectrophotometric analysis conditions to determine carmoisine in the extractant phase. The optimized limit of detection (LOD), limit of quantification (LOQ), and preconcentration factor were 3.3 µg L−1, 11.1 µg L−1, and 10, respectively. The advantages of this approach are low solvent consumption and rapid analysis. The method analyzed candy and water samples with recoveries from 94% to 108%.

Novel deep eutectic solvent-based liquid phase microextraction for the extraction of estrogenic compounds from environmental samples.

Steroid hormones, such as estrone (E1), 17β-estradiol (E2), 17β-ethinylestradiol (EE2) and estriol (E3) are a group of lipophilic active substances, synthesized biologically from cholesterol or chemically. A pH-switchable hydrophobic deep eutectic solvent-based liquid phase microextraction (DES-LPME) technique was established and combined with gas chromatography-mass spectroscopy for the determination of estrogenic compounds in environmental water and wastewater samples. A DES was synthesized using l-menthol as HBA and (1S)-(+)-camphor-10-sulfonic acid (CSA) as HBD, and used as a green extraction solvent. By adjusting the pH of the solution, the unique behavior of the DES in the phase transition and extraction of the desired analytes was investigated. The homogenization process of the mixture is done only by manual shaking in less than 30 seconds and the phase separation is done only by changing the pH and without centrifugation. Some effective parameters on the extraction and derivatization, such as molar ratio of DES components, DES volume, KOH concentration, HCl volume, salt addition, extraction and derivatization time and derivatization prior or after extraction were studied and optimized. Under the optimum conditions, relative standard deviation (RSD) values for intra-day and inter-day of the method based on 7 replicate measurements of 20 ng L−1 of estrogenic compounds and 10 ng L−1 for internal standard in different samples were in the range of 2.2–4.6% and 3.9–5.7%, respectively. The calibration graphs were linear in the range of 0.5–100 ng L−1 and the limits of detection (LODs) were in the range of 0.2–1.0 ng L−1. The relative recoveries of environmental water and wastewater samples which have been spiked with different levels of target compounds were 91.0–108.8%.

Development of in-situ synthesis of lighter than water deep eutectic solvents under ultrasonic energy in a narrow tube and application in liquid–phase microextraction

ABSTRACT Evaluation of sonication energy effect on in-situ synthesis of deep eutectic solvent-based liquid phase microextraction process was performed in fresh fruit samples for extraction of five neonicotinoids insecticide including clothianidin, imidacloprid, nitenpyram, acetamiprid, and thiacloprid. A suitable amount of choline chloride was dissolved in sample solution and it was poured into a glass narrow-bore tube. Then, a sodium chloride tablet was taken and a few microlitres of hexanoic acid were penetrated into the tablet and it was released into the tube. The narrow–bore tube was located into an ultrasonic bath at controlled frequency and power. The sodium chloride tablet started to dissolve and hexanoic acid was released into the solution and hydrogen bonding was correlated between the ChCl and hexanoic acid. The formed deep eutectic solvent went up through the sample solution and analytes were extracted into the ChCl: hexanoic acid DES. Validation parameters were calculated and low limits of detection (0.04–0.31 ng mL–1) and quantification (0.13–1.03 ng mL–1), high enrichment factors (1280–1780) and extraction recoveries (64–89%), and acceptable precision (RSD ≤7.2%) were obtained. Lastly, the procedure was done on some fresh fruit samples imidacloprid and acetamiprid were detected on some samples.

Determination of Trace Nickel in Spinach Samples Using the Combination of Vortex-assisted Deep Eutectic Solvent-based Liquid Phase Microextraction and Slotted Quartz Tube - Flame Atomic Absorption Spectrometry

Determination of Trace Nickel in Spinach Samples Using the Combination of Vortex-assisted Deep Eutectic Solvent-based Liquid Phase Microextraction and Slotted Quartz Tube - Flame Atomic Absorption Spectrometry

A new green microextraction method for traces Brown HT (E155) by using deep eutectic solvents prior to its spectrophotometric determination

ABSTRACT A method for determination of Brown HT with UV-Vis spectrophotometer after separation and preconcentration by deep eutectic solvent-based liquid phase microextraction was developed. Tetrabutylammonium bromide and decanoic acid were used to get deep eutectic solvent. Important analytical parameters effective on the method were optimised such parameters are deep eutectic solvent type and volume, sample volume, matrix effects and tetrahydrofuran volume. Brown HT in the model solution was quantitatively extracted at the pH 4.0 to the deep eutectic solvent phase. In this study, the limit of detection (LOD) value and preconcentration factor were found to be 0.23 μg mL−1 and 37.5, respectively. The method was applied to the determination of Brown HT content of cake, artificial urine and water samples.

Determination of lead in milk samples using vortex assisted deep eutectic solvent based liquid phase microextraction-slotted quartz tube-flame atomic absorption spectrometry system

Determination of lead at trace levels was achieved by slotted quartz tube-flame atomic absorption spectrometry (SQT-FAAS) after the preconcentration with deep eutectic solvent-based liquid phase microextraction (DES-LPME). A green solvent was used to extract lead from the aqueous solution. Parameters affecting the extraction efficiency and determination were optimized in the aim to lower the detection limit. Under the optimum experimental and instrumental conditions, the proposed method exhibited a linear range between 50 and 1000 µg L−1, and the limits of detection and quantitation (LOD and LOQ) were found to be 8.7 and 29.0 μg L−1, respectively. The detection power was improved by 48 times using DES-LPME-SQT-FAAS method with respect to conventional FAAS system. Recovery studies were carried out in raw milk samples to check the accuracy and the applicability of the developed method and the percent recoveries obtained were between 102.5 and 103.2% for the spiked raw milk samples.

Deep eutectic solvent-based liquid phase microextraction for the determination of pharmaceuticals and personal care products in fish oil

The analytical method of PPCPs in fish oil was first developed based on the green solvent DES.