Homogeneous Liquid-liquid Microextraction Research Articles

Amine Switchable Hydrophilic Solvent Vortex-Assisted Homogeneous Liquid-Liquid Microextraction and GC-MS for the Enrichment and Determination of 2, 6-DIPA Additive in Biodegradable Film.

2, 6-diisopropylaniline (2, 6-DIPA) is a crucial non-intentionally organic additive that allows the assessment of the production processes, formulation qualities, and performance variations in biodegradable mulching film. Moreover, its release into the environment may have certain effects on human health. Hence, this study developed simultaneous heating hydrolysis-extraction and amine switchable hydrophilic solvent vortex-assisted homogeneous liquid-liquid microextraction for the gas chromatography-mass spectrometry analysis of the 2, 6-DIPA additive and its corresponding isocyanates in poly(butylene adipate-co-terephthalate) (PBAT) biodegradable agricultural mulching films. The heating hydrolysis-extraction conditions and factors influencing the efficiency of homogeneous liquid-liquid microextraction, such as the type and volume of amine, homogeneous-phase and phase separation transition pH, and extraction time were investigated and optimized. The optimum heating hydrolysis-extraction conditions were found to be a H2SO4 concentration of 2.5 M, heating temperature of 87.8 °C, and hydrolysis-extraction time of 3.0 h. As a switchable hydrophilic solvent, dipropylamine does not require a dispersant. Vortex assistance is helpful to speed up the extraction. Under the optimum experimental conditions, this method exhibits a better linearity (0.0144~7.200 μg mL-1 with R = 0.9986), low limit of detection and quantification (0.0033 μg g-1 and 0.0103 μg g-1), high extraction recovery (92.5~105.4%), desirable intra- and inter-day precision (relative standard deviation less than 4.1% and 4.7%), and high enrichment factor (90.9). Finally, this method was successfully applied to detect the content of the additive 2, 6-DIPA in PBAT biodegradable agricultural mulching films, thus facilitating production process monitoring or safety assessments.

Aqueous two-phase system based on hexafluoroisopropanol and acetonitrile for homogeneous liquid-liquid microextraction of cationic dyes


 
 
 
 This work demonstrates that an aqueous two-phase system (ATPS) is formed when a small amount of acetonitrile (ACN) is added to the aqueous hexafluoroisopropanol (HFIP) solution. The effect of ACN amount on the volume of the formed HFIP/ACN phase was investigated. It was also shown that relatively hydrophilic methylene blue was completely extracted into the HFIP/ACN phase whereas its extractability with conventional solvents (hexane, CH2Cl2 and CHCl3) was significantly lower. The obtained results suggest that the HFIP/ACN phase exhibits a relatively high polarity and should be a good choice for the extraction of moderately or even highly polar compounds from aqueous samples. Finally, the developed ATPS was applied for the homogeneous liquidliquid microextraction of four cationic dyes from river water samples prior to HPLC analysis. Under optimised extraction conditions, the enrichment factors were around 150. Calibration curves were linear (R2 ≥ 0.9959) for the concentration level between 0.2–0.5 and 50.0 μg/L and the detection limits were in the range 0.05–0.18 μg/L. The recoveries of the dyes for the spiked water samples were 88.6–98.5%, with the relative standard deviation values less than 9.6%.
 
 
 

Ternary solvent based homogeneous liquid-liquid microextraction for the preconcentration of organochlorine pesticides from water and apple juice samples.

In the present study, the optimal experimental conditions were determined by optimizing the effect of extraction solvent types and volume, salt types and concentration, centrifugation speed and time using one variable at a time. Under optimal experimental conditions, calibration curves were constructed separately using water and apple juice samples as representative matrices, and good linearities were achieved over a wide concentration range of 0.2-1600 ng L-1 with a coefficient of determination (r2) ≥ 0.998. The limits of detection (LOD) and limits of quantification (LOQ), determined to be 3 and 10 times the signal-to-noise ratios (S/N), were between 0.07-3.9 and 0.2-12.0 ng L-1 for water samples and 2.6-10.0 and 8.0-30.0 ng L-1 for the apple juice sample respectively. The precisions study showed %RSD values of ≤6% for both matrices, indicating satisfactory precisions. The enrichment factors and recoveries of the proposed method ranged from 41.4-74.5 and 86-109% respectively. The proposed method could be used as a simple and environmentally friendly alternative for the analysis of OCPs from environmental and food matrices. This method potentially offers a more sustainable and effective approach to monitoring OCPs in environmental and food products. Its use in the analysis of apple juice samples is particularly novel and can provide valuable insights into pesticide contamination in fruit juices.

Combination of switchable hydrophilic solvent liquid-liquid microextraction with QuEChERS for trace determination of triazole fungicide pesticides by GC-MS.

This work first proposed a novel green and efficient method based on Quick, Easy, Cheap, Efficient, Rugged, and Safe pretreatment (QuEChERS) combined with switchable hydrophilic solvent homogeneous liquid-liquid microextraction (SHS-HLLME) for trace determination of triazole fungicides (TFs) in agricultural products such as vegetables and fruits by gas chromatography-mass spectrometry (GC-MS). N,N-Dimethyl benzylamine was used for the synthesis of SHS. Box-Behnken design was applied for the optimization of extraction conditions and a mathematical model was obtained. Ultimately, 0.50mL SHS, 1.0mL 10molL-1 sodium hydroxide, and 45s ultrasonic time were determined as optimal conditions for the SHS-HLLME method. The limit of detection and limit of quantification determined using the optimal method (SHS-HLLME/GC-MS) were 0.13-0.27ngmL-1 and 0.43-0.90ngmL-1, respectively. In addition, the SHS-HLLME method under optimal conditions was combined with the traditional QuEChERS method to realize the advancement of the SHS-HLLME method from simple to complex matrix analysis, and the QuEChERS-SHS-HLLME method was successfully applied to the analysis of TFs in cucumbers, tomatoes, watermelon and grapes in agricultural products. Matrix-matched calibration standards were used to improve the accuracy of TFs in spiked cucumber samples to obtain recovery results close to 100%. It was shown that the new method is green and rapid, enabling fast and inexpensive sample pretreatment with up to 100-fold enrichment factor and low detection limit compared with the original QuEChERS method.

Determination of copper(II) and lead(II) ions in dairy products by an efficient and green method of heat-induced homogeneous liquid-liquid microextraction based on a deep eutectic solvent.

In this study, a new homogeneous liquid-liquid microextraction method using a deep eutectic solvent has been developed for the extraction of Cu(II) and Pb(II) ions in dairy products. Initially, the deep eutectic solvent was synthesized using choline chloride and p-chlorophenol and used as the extraction solvent. The synthesized solvent was soluble in milk at 70 °C and its separation from the sample was performed by decreasing the temperature. By cooling, a cloudy solution was formed due to the low solubility of the solvent at low temperatures. On centrifugation, the fine droplets of the solvent containing the analytes settled at the bottom of the tube by sedimentation. The enriched analytes were determined by flame atomic absorption spectrometry. The effect of some important parameters such as the amount of protein precipitating agent , complexing agent amount, extraction solvent volume, salt addition, pH, and temperature on the extraction efficiency of the method was studied and optimized. Under the optimal conditions, the linear ranges of the method for Cu(II) and Pb(II) ions were obtained in the ranges of 0.10-50 and 0.50-50 μg L-1 with detection limits of 0.04 and 0.18 μg L-1, respectively. The repeatability of the developed method, expressed as relative standard deviation, was determined to be 3.2 and 3.9% for Cu(II) and Pb(II) ions, respectively. Finally, by determining the concentration of Cu(II) and Pb(II) ions in milk, doogh, and cheese samples, the feasibility of the method was successfully confirmed with the extraction recoveries of 95.9 and 92.1% for Cu(II) and Pb(II) ions, respectively.

A switchable deep eutectic solvent for the homogeneous liquid-liquid microextraction of flavonoids from “Scutellariae Radix”

A homogeneous liquid-liquid microextraction (HLLME) was established based on a switchable deep eutectic solvent (DES) for the preconcentration and determination of six flavonoids with different polarity in “Scutellariae Radix” combined with high performance liquid chromatography (HPLC). A switchable DES composed of N,N-dimethylethanolamine (DMEA) and heptanoic acid was used as an extraction solvent in the HLLME method, which was miscible thoroughly with the aqueous sample phase initially, and then underwent rapid phase transition induced by the addition of an inorganic acid. After the extraction, the upper hydrophobic layer was recovered for HPLC analysis. Different experimental parameters were optimized, and the optimal extraction conditions were as follows: the switchable DES extraction phase, 90 µL of DMEA-heptanoic acid (1:1 mole ratio); phase-switching trigger, 100 µL of 5 mol/L HCl; 10% (w/v) of salt concentration in sample phase; extraction time, 0.3 min. Furthermore, the structures of the switchable DES and the upper hydrophobic layer were characterized by Fourier transform infrared spectroscopy, proton nuclear magnetic resonance spectroscopy and differential scanning calorimetry to illustrate the phase-switching mechanism of the extraction phase during the extraction process. Under the optimized conditions, the enrichment factors for six target analytes were between 0.4 and 104. The calibration curves were linear (r≥0.9866) in the range of 0.033–8.65 mg/L for scutellarin, 0.022–5.77 mg/L for baicalin, 0.0033–0.865 mg/L for scutellarein and wogonoside, and 0.0022–0.577 mg/L for baicalein and wogonin, respectively. Low detection limits (≤8.0 × 10−3 mg/L) and quantification limits (≤2.4 × 10−2 mg/L) as well as good precisions (relative standard deviations lower than 9.2%) and acceptable accuracies (spiked recoveries 89.3–114.4%) were also obtained. The proposed method is a simple, fast, and eco-friendly sample pretreatment method.

Green homogeneous liquid-liquid microextraction at high salinity conditions for the determination of nimesulide in human urine with the aid of experimental design

Green homogeneous liquid-liquid microextraction (HLLME) under high salinity conditions was proposed for the determination of nimesulide in human urine. The proposed analytical scheme consisted of the mixing of the appropriate volume of acetonitrile and sample followed by the addition of Na2SO4 solution to obtain phase separation. Following the extraction of the drug from the urine samples, high-performance chromatography-diode array detection (HPLC-PDA) was used for its determination. The main factors influencing the performance of the HLLME method were studied and optimized using a two-step experimental design (Plackett-Burman, Central Composite Design). The HLLME-HPLC-PDA method was systematically validated using the accuracy profiles. The detection limit was adequate and estimated to be 0.03 μg mL−1. The mean analytical bias (expressed as relative error) ranged between ─ 2.9–3.6% and the relative standard deviation (RSD) was better than 3.7%. Moreover, the β-expectation tolerance intervals were in the range of ±15% demonstrating that 95% of the results will fall within the defined bias limits. The ruggedness of the herein developed protocol was assessed using Monte-Carlo simulations followed by capability analysis. The proposed scheme was applied for the determination of the drug in real urine samples following the administration of pharmaceutical formulations that contained nimesulide.

A successive homogeneous liquid-liquid microextraction based on solidification of switchable hydrophilicity solvents and ionic liquids for the detection of pyrethroids and cadmium in drinks

A simple, efficient, and environmentally friendly method for the determination of pyrethroids and cadmium in drink samples was developed by successive homogeneous liquid-liquid microextraction (SHLLME) based on switchable hydrophilicity solvents and ionic liquids coupled with high-performance liquid chromatography-diode array detector (HPLC-DAD) and graphite furnace atomic absorption spectrometry (GFAAS) detection. The extraction of pyrethroids needs to be conducted under acidic conditions, while cadmium needs to be extracted under neutral or slightly alkaline conditions. In SHLLME, hydrophobic fatty acids and ionic liquids were generated in situ as extraction solvents for pyrethroids and cadmium, respectively. Acidic ionic liquids and sodium carbonate were successively applied to adjust the pH value of the sample solution. The SHLLME procedure was optimized by univariate analysis and the Box-Behnken response surface methodology. Optimum conditions were as follows: 105 mg of sodium decanoate, 246 mg of [Emim][HSO4], 131 mg of sodium fluoroborate amount, and 128 mg of sodium carbonate. Under optimized conditions, the extraction recovery varied from 77.0% to 97.2%, and relative standard deviations varied from 0.5% to 4.5%. The limits of detection were 0.6 μg L−1 and 0.006 μg L−1 for pyrethroids and cadmium, respectively. This established method has the potential to continuously extract compounds with different physical and chemical properties.

Switchable deep eutectic solvent‐based homogenous liquid–liquid microextraction combined with high‐performance liquid chromatography–diode‐array detection for the determination of the chiral fungicide mefentrifluconazole in water, fruit juice, and fermented liquor

A switchable deep eutectic solvent-based homogeneous liquid-liquid microextraction (SDES-HLLME) technique was developed and combined with high-performance liquid chromatography-diode-array detection for the determination of the chiral fungicide mefentrifluconazole. A (green) SDES was synthesized from 4-methoxyphenyl and 3-amino-1-propanol and used as an extraction solvent (thus avoiding the use of toxic extraction solvents). To improve the efficiency of the extraction process, a hydrophobic extraction solvent was subsequently generated in situ by adjusting the pH. The detection process is linear in the range of 0.01 to 1μg ml-1 . The limit of detection and limit of quantification were determined to be 0.003 and 0.01 μg ml-1 , respectively. Recovery rates of 79.2% to 104.6% were acquired with relative standard deviations of 0.6% to 2.5%. The method is fast, simple, and environmentally friendly. Moreover, it was successfully used to enantioselectively determine the concentrations of mefentrifluconazole residues in water, fruit juice, and fermented liquor samples.

Rapid and efficient determination of zinc in water samples by graphite furnace atomic absorption spectrometry after homogeneous liquid-liquid microextraction via flotation assistance

ABSTRACT. A new application of homogeneous liquid–liquid microextraction via flotation assistance (HLLME-FA) has been developed for the determination of Zn(II) in the water samples by using graphite furnace atomic absorption spectrometry (GFAAS). 1-(2-Pyridylazo)-2-naphthol (PAN) was used as a chelating reagent. In this work, low density organic solvent was used as an extraction solvent and no centrifugation was required in this method. A special extraction cell was designed to facilitate collection of the low density extraction solvent. The predominant parameters influencing the HLLME-FA procedure, such as solution pH, concentration of PAN, extraction and homogeneous solvent types and volumes, ionic strength, and extraction time have been optimized. Applying all the optimum conditions in the process, the detection limit of 0.1 μg/L, linear range of 0.5–200 μg/L, and the precision (RSD%, n = 10) of 5.7% were obtained for zinc. The proposed procedure showed satisfactory results for the analysis of tap water, well water and sea water.
 
 KEY WORDS: Homogeneous liquid-liquid microextraction, Flotation assistance, Zinc, Graphite furnace atomic absorption spectrometry, Water samples
 Bull. Chem. Soc. Ethiop. 2022, 36(1), 1-11. 
 DOI: https://dx.doi.org/10.4314/bcse.v36i1.1

Salting-out homogeneous liquid-liquid microextraction for the determination of azole drugs in human urine: Validation using total error concept.

A salting-out homogeneous liquid-liquid microextraction was proposed for the quantification of four azole drugs in human urine prior to high-performance liquid chromatography analysis. The procedure involved the mixing of the sample with acetonitrile in appropriate volumes followed by the addition of sodium sulfate solution in order to facilitate phase separation. The parameters influencing the extraction performance were studied and optimized using a two-step experimental design. The analytical procedure was thoroughly validated using the accuracy profiles as a graphical decision-making tool. The β-expectation tolerance intervals did not exceed the acceptance criteria of ±15% meaning that 95% of future results will be included in the defined bias limits. The limits of detection of the procedure were satisfactory, ranging between 0.01 and 0.03 μg/mL. The mean analytical bias in the spiking levels was satisfactory and ranged between -10.3 and 4.2% while the relative standard deviation was lower than 5.6%. Monte-Carlo simulations followed by capability analysis were employed to investigate the ruggedness of the sample preparation protocol. The developed method offers advantages compared to previously reported approaches for the same type of analysis including extraction efficiency and scaling down of the sample volume and extraction time.

Homogeneous Liquid-Liquid Microextraction Based on Deep Eutectic Solvents

Homogeneous Liquid-Liquid Microextraction Based on Deep Eutectic Solvents

Application of an In-situ Solvent Formation Microextraction Technique Using the Functionalized Ionic Liquids (FILs) as a Green Extractant for Cadmium Determination at Trace Levels in Real and Saline Samples

An in-situ solvent formation microextraction technique as another attractive mode of homogeneous liquid-liquid microextraction, was developed successfully for the sensitive extraction of cadmium ion. In this technique use green extracting solvent such as ionic liquids that are environment lover. So, because using ionic liquids, this technique is much safer than other extraction methods which use toxic common organic solvents. Functionalized ionic liquid of 3-(2-(bis(2-(tert-butoxy)-2-oxoethyl)amino)ethyl)-1-methylimidazolium bromide was used as extractant and organic phase which has double role including complexing agent and extractant, so to extraction of cadmium ion, not need to any complexing agent. To optimization of extraction conditions, several analytical parameters affected on microextraction efficiency including sample pH, functionalized ionic liquid dosage, counter-ion amount and centrifugation conditions were studied. To show abilities of the method, the figures of merits including limit of detection and quantification, relative standard deviation, linear dynamic range and enrichment factor were calculated and included 0.23 µg/L, 0.76 µg/L, 1.8%, 10-1500 µg/L and 75, respectively. It was found from results that the method was applied successfully for the determination of Cd (II) ion in several real, and saline samples. Because of use environmental solvents such as ionic liquids, and very small dosage of its, it can be said the method has low toxicity and classified as a green extraction/preconcentration technique. One the other hand, the presented method opens a new window in the analytical applications due to its costless, ease in experimental setup and use of non toxic solvents as an extractant.

Ultrasonic in Situ Generation of Co2-Assisted Citric Acid Type Switchable Hydrophilic Solvent Based Homogeneous Liquid-Liquid Microextraction Combined with Gc-Ms: To Extract and Detect the Triazole Fungicides in Environmental Water

Ultrasonic in Situ Generation of Co2-Assisted Citric Acid Type Switchable Hydrophilic Solvent Based Homogeneous Liquid-Liquid Microextraction Combined with Gc-Ms: To Extract and Detect the Triazole Fungicides in Environmental Water

Menthol-assisted homogenous liquid-liquid microextraction for HPLC/UV determination of favipiravir as an antiviral for COVID-19 in human plasma

Favipiravir is a promising antiviral agent that has been recently approved for treatment of COVID-19 infection. In this study, a menthol-assisted homogenous liquid–liquid microextraction method has been developed for favipiravir determination in human plasma using HPLC/UV. The different factors that could affect the extraction efficiency were studied, including extractant type, extractant volume, menthol amount and vortex time. The optimum extraction efficiency was achieved using 300 µL of tetrahydrofuran, 30 mg of menthol and vortexing for 1 min before centrifuging the sample for 5 min at 3467g. Addition of menthol does not only induce phase separation, but also helps to form reverse micelles to facilitate extraction. The highly polar favipiravir molecules would be incorporated into the hydrophilic core of the formed reverse micelle to be extracted by the non-polar organic extractant. The method was validated according to the FDA bioanalytical method guidelines. The developed method was found linear in the concentration range of 0.1 to 100 µg/mL with a coefficient of determination of 0.9992. The method accuracy and precision were studied by calculating the recovery (%) and the relative standard deviation (%), respectively. The recovery (%) was in the range of 97.1–103.9%, while the RSD (%) values ranged between 2.03 and 8.15 %. The developed method was successfully applied in a bioequivalence study of Flupirava® 200 mg versus Avigan® 200 mg, after a single oral dose of favipiravir administered to healthy adult volunteers. The proposed method was simple, cheap, more eco-friendly and sufficiently sensitive for biomedical application.

Development of sodium hydroxide-induced homogenous liquid-liquid extraction-effervescent assisted dispersive liquid-liquid microextraction based on deep eutectic solvents; Application in the extraction of phytosterols from cow cream samples

In this study, sodium hydroxide-induced homogenous liquid-liquid extraction was combined with effervescent assisted-dispersive liquid-liquid microextraction and used for the extraction of phytosterols (lupeol, β-sitosterol, stigmasterol, campesterol, and brassicasterol) from cream samples. Two types of deep eutectic solvents (water-miscible and water-immiscible solvents) were prepared and used in the extraction procedure. In this approach, firstly, the sample was dissolved in a mixture of n-hexane and tetrabutylammonium bromide: ethylene glycol deep eutectic solvent (as extraction/disperser solvent) and a homogenous solution was obtained. After that, a few microliters of sodium hydroxide solution (as fatty acid saponification and phase separation agent) was quickly injected into the mixture. By doing so, a three-phase system was formed. Then, the supernatant phase (tetrabutylammonium bromide: ethylene glycol deep eutectic solvent) was removed and mixed with tetrabutylammonium bromide: dichloroacetic acid: octanoic acid deep eutectic solvent. The obtained solution was applied in the microextraction step. To obtain effective, reliable, robust, accurate, and precise analytical results, the effective parameters for the presented method were investigated and optimized in detail. Detection limits, extraction recoveries, and enrichment factors were in the ranges of 0.06–0.26 μg kg–1, 86–93 %, and 215–232, respectively. Intra- and inter-day repeatabilities were investigated at a concentration of 1.5 μg kg–1 (each analyte) and they were in the ranges of 5.3−7.5 and 7.2–8.8 %, respectively. Finally, the presented method was easily used in determination of the phytosterols in cow milk cream samples.

Rapid in-syringe-based ultrasonic-energy assisted salt-enhanced homogeneous liquid-liquid microextraction technique coupled with HPLC/low-temperature evaporative light-scattering detector for quantification of sodium hyaluronate in food products

Sodium-hyaluronate (Na-HA) is a biopolymer-based active ingredient in various dietary and beauty care supplements. However, the existing analytical methods for Na-HA analysis are laborious, less sensitive, and time-consuming. This study demonstrates a simple, low-cost, and green rapid analytical methodology using a novel in-syringe-based ultrasonic energy-assisted salt-enhanced homogeneous liquid-liquid microextraction (IS-USE-SE-HLLME) technique coupled with HPLC/low-temperature evaporative light scattering detector (LT-ELSD) for the sensitive quantification of Na-HA in nutraceutical products. This method utilizes ultrasound energy to extract Na-HA from an aqueous sample solution using a low volume water-miscible extraction solvent with a high salt concentration. Size-exclusion column-based HPLC was applied to separate target Na-HA from co-matrices and quantified using LT-ELSD for sensitive analysis. Under optimal conditions, excellent linearity was observed between 1 and 500 ng mL−1 with a correlation coefficient of 0.9974. Detection and quantification limits were 0.5 ng mL−1 and 1.0 ng mL−1, respectively. The developed (IS-USA-SE-HLLME/HPLC-LT-ESLD) method was applied to analyze Na-HA in commercial nutraceutical and beauty care products. Spiked recoveries of real samples showed between 96.1 and 105.9%, with the precision <7.52%, indicating no matrices influence and good accuracy of the method. These results proved that the developed method is a fast, inexpensive, sensitive, and eco-friendly method for quantifying Na-HA in nutraceutical products. Therefore, the presented method can be applied as an alternative standard analytical method to monitor Na-HA concentrations in food products for food safety regulatory purposes.

Switchable hydrophilicity solvent based homogeneous liquid-liquid microextraction for enrichment of pyrethroid insecticides in wolfberry

A simple and sensitive homogeneous liquid–liquid microextraction based on switchable hydrophilicity solvent (SHS-HLLME) has been developed for fast enrichment and determination of pyrethroid insecticides in wolfberry samples via HPLC-UV. In HLLME, N, N-dimethylbenzylamine (DMBA) was used as SHS that can reversibly convert between water-insoluble and water-soluble states by applying CO2 as trigger. Two phase separation was easily achieved by addition of NaOH solution without need of time-consuming of salting-out or forming ionpair, greatly shortening extraction time (3 min). The influencing extraction parameters were investigated and optimized in detail. Under the optimal condition, the method shows good linearity (1.0–200 ng/mL), low limits of detection (0.2–0.5 ng/mL), desirable precision (RSD < 9.8%) and accuracy (RE < 8.7%) and acceptable extraction recovery (71.4%-94.1%). The work provides a novel alternative approach for determination of pyrethroid insecticides at the low nanogram per microliter range with desirable sensitivity.

A green homogeneous liquid-liquid microextraction method for spectrophotometric determination of daclatasvir in human plasma

Spectroscopic determination of drugs in biological fluids is challenging due to the matrix effect and the expected low therapeutic levels. In this work, we employed salting-out induced homogenous liquid-liquid microextraction for preparation and pre-concentration of daclatasvir in human plasma to be measured by second derivative spectrophotometry. The procedures included vortexing 500 μL of acetonitrile with 500 μL of the daclatasvir-containing plasma, and centrifuging for 5 min at 4000 rpm before transferring 600 μL of the upper layer to another test tube, and making up the volume to 1 mL with alkaline water (pH 7.5). Then, 200 mg of ammonium acetate were added and the tube was centrifuged for 5 min at 4000 rpm, to induce phase separation of an upper layer of acetonitrile that could be measured in a quartz microcuvette. The calibration curve was constructed by plotting the daclatasvir concentrations in ng/mL versus the amplitude of second derivative spectra at 357 nm. The proposed method was found linear in the concentration range of 500–5000 ng/mL (r2 = 0.9991), with a limit of detection of 130 ng/mL. The method was accurate and precise with a % recovery, ranging between 99.70% and 101.51%. The developed method was simple, rapid, cost-effective and required minimal amounts of organic solvents compared with conventional liquid-liquid extraction techniques. The method greenness was evaluated using the Green Analytical Procedure Index (GAPI) and the Analytical Eco-Scale. This application sheds the light on the potential of using SALLME as a sample preparation method in spectroscopic biomedical applications.

Development of a deep eutectic solvent-based ultrasound-assisted homogenous liquid-liquid microextraction method for simultaneous extraction of daclatasvir and sofosbuvir from urine samples

An ultrasound-assisted homogenous liquid–liquid microextraction method using a new deep eutectic solvent was proposed for the extraction of daclatasvir and sofosbuvir from urine. The analytes were determined by high performance liquid chromatography–diode array detector. The deep eutectic solvent was prepared by mixing p-aminophenol with tetrabutyl ammonium chloride. It was used in the extraction procedure as an extraction solvent. The amine group in structure of the prepared deep eutectic solvent led to its various solubility in different pHs. In this method, urine sample was placed in a glass test tube and then mixed with sodium chloride and its temperature adjusted at 50 °C. Then, the deep eutectic solvent was dissolved in the solution by manually shaking. In the following, an ammonia solution was added to the solution and the mixture was sonicated for 4 min. After centrifugation, an aliquat of the sedimented phase was injected into the determination system. Low limits of detection (daclatasvir 1.0 and sofosbuvir 1.3 μg/L) and quantification (daclatasvir 3.3 and sofosbuvir 4.0 μg/L), high enrichment factor (daclatasvir 96 and sofosbuvir 90) and extraction recovery (daclatasvir 96 and sofosbuvir 90 %), and good percision (relative standard deviation ≤9.3 %) were obtained. The introduced method was successfully applied in the determination of daclatasvir and sofosbuvir concentrations in urine samples.