Ultrasonic-assisted Dispersive Liquid-liquid Microextraction Research Articles

A novel organoselenium-based Schiff base for selective separation of copper and zinc from food samples using ultrasonic-assisted solidified floating organic drop microextraction strategy

Herein, we document the development of a novel organoselenium-based Schiff base, 2-((4-((2-hydroxy-4-nitrobenzylidene)amino)phenyl)selanyl)-N-phenylacetamide (HOASe), to selectively separate zinc and copper from food samples. To the best of our knowledge, OSe compound has never been used in microextraction procedures before, until today. HOASe was synthesized from aniline by a simple four-step procedure. The structure of HOASe was elucidated by various spectroscopic techniques (e.g., IR, MS, 1H- and 13C NMR). After that, HOASe was used to extract Cu2+ and Zn2+ by ultrasonic-assisted dispersive liquid-liquid microextraction based on the solidification of floating organic drop (UA-DLLME-SFOD) combined with flame atomic absorption spectrometry. Important experimental parameters including amount of the extraction solvent, initial pH, amount of HOASe, ultrasonication time, centrifugation, and salt addition, were studied and optimized to offer quantitative separation of the analytes. The detection limits and the linear ranges for Cu2+ and Zn2+ were 1.9, 8.0 – 400.0, and 2.4, 6 – 150 μg L-1, respectively. The method's greenness and applicability were assessed using the Analytical GREEnness metric methodology and the Blue Applicability Grade Index, respectively. Finaly, this approach was used for quantification of Cu2+ and Zn2+ in food samples and, therefore, can be further developed for food safety and quality control programs.

Evaluate the aluminum concentrations in whey milk samples of cows from different areas using deep eutectic solvent-based ultrasound-assisted dispersive liquid-liquid microextraction method

This study investigates the contamination of cow milk with aluminum (Al) and its potential health implications, particularly for children. Cow milk samples were collected from both nonexposed and exposed areas in Sindh, based on the source of livestock drinking water (fresh canals and groundwater). An environmental friendly deep eutectic solvent (DES) was used with ultrasonic-assisted dispersive liquid-liquid microextraction (UDLLμE) to enrich trace amounts of Al in whey milk and water samples. The enriched samples were then analyzed using inductively coupled plasma optical emission spectrometry. Certified reference materials were employed to validate the methodology, and the experimental results exhibited acceptable conformity. The DES-based dispersive liquid-liquid microextraction method was environmental friendly, devoid of acids and oxidizing agents, and used safe and inexpensive components for routine trace metal analysis in diverse samples. The resulting data revealed that Al in whey milk samples was observed in the range of 31–45 %, corresponding to (160–270) μg L−1 and (700–1035) μg L−1 in nonexposed and exposed whole cow milk samples, respectively. Additionally, it was observed that milk boiling in Al utensil for 10–20 min enhanced the Al levels from 3 to 8% of its total contents in milk samples.

Application of chemometric modeling for ionic liquid-based ultrasonic-assisted dispersive liquid-liquid microextraction: Analysis of fosetyl-aluminum in fruit and vegetable samples

This manuscript presents a new method for selective extraction and determination of fosetyl-aluminum in fruits and vegetable samples based on ultrasonic-assisted dispersive liquid-liquid microextraction method using ionic liquids (IL-UA-DLLME). A UV-Visible spectrophotometer was used for detection and quantification. Plants used for sample collection were grown under controlled conditions in a greenhouse. Central composite design (CCD)-response surface methodology (RSM) analysis was used for the optimization of significant factors (volume of IL, pH, ultrasonication time, and THF volume). Under optimal conditions, the limit of detection and limit of quantification of the IL-UA-DLLME procedure were 1.5 ng mL−1 and 5.0 ng mL−1 respectively with relative standard deviation 1.9–3.3%. The developed IL-UA-DLLME procedure demonstrated linearity within the concentration range of 5–600 ng mL−1 with an R2 value of 0.9914. The enrichment factor was 114 with a recovery% of 94.2–98.6% (n = 3) at optimal conditions. The IL-UA-DLLME assay was used for the analysis of fosetyl-aluminum in a variety of food samples and was found highly selective and efficient.

Smartphone-based colorimetric determination of triclosan in aqueous samples after ultrasound assisted-dispersive liquid–liquid microextraction under optimized response surface method conditions

In the present study, a simple and low cost methodology based on ultrasonic assisted-dispersive liquid–liquid microextraction (UA-DLLME) followed by smartphone-based colorimetric measurement was introduced for the separation and determination of Triclosan (TCS) from contaminated waters. This method is based on the formation of an azo compound from the alkaline reaction of TCS with a diazonium ion, resulting from the reaction of sodium nitrite and p-sulfanilic acid in an acidic medium. The orange-brown color product was extracted into a low volume of organic phase by UA-DLLME method and RGB values were recorded with free Android app Color Grab. The effective parameters in this procedure, namely solution pH, p-sulfanilic acid and nitrite concentration, reaction time and volume of the extraction solvent were investigated and optimized by response surface methodology (RSM) based on a Box-Behnken design (BBD) model. Under optimum conditions, the calibration graph was linear in the range of 3.0 and 200 μg L-1 of TCS. The limit of detection (LOD) and limit of quantification (LOQ) were 0.8 and 2.7 μg L-1, respectively. The proposed method was successfullyused for the analyses of triclosan in several water and wastewater samples and satisfactory results were obtained.

Simultaneous Determination of Sulfonamides Antibiotics in Environmental Water and Seafood Samples Using Ultrasonic-Assisted Dispersive Liquid-Liquid Microextraction Coupled with High Performance Liquid Chromatography.

The residues and abuse of antibiotics have seriously endangered ecological balance and human health; meanwhile, antibiotics determination is very difficult because of their low levels and multiple categories in complicated matrices. Appropriate sample pretreatment is usually imperative to enrich (ultra)trace antibiotics and eliminate matrix interference prior to chromatographic analysis. Dispersive liquid-liquid microextraction (DLLME) has become an ideal pretreatment technique owing to its simplicity, effectiveness, low-consumption, etc. In this work, an ultrasonic-assisted DLLME (UA-DLLME) was developed for the simultaneous extraction of seven sulfonamides (SAs) antibiotics in environmental water and seafood samples coupled with HPLC-DAD determination. Several parameters affecting UA-DLLME efficiency were systematically optimized, and consequently the SAs were separated and detected within 14.5 min. The obtained limits of detection (LODs) and limits of quantification (LOQs) ranged from 0.7–7.8 μg/L and 2.4–26.0 μg/L for three water samples (seawater, aquaculture wastewater and lake water) and two seafood samples (pomfrets and shrimps). High recoveries (80.0–116.0%) with low relative standard deviations (0.1–8.1%) were achieved for all the tested samples at three spiked levels. Notably, sulfadimethoxine was found at 24.49 μg/L in one seawater sample. The facile, robust and benign DLLME-HPLC method demonstrated promising perspectives for multiresidue analysis of antibiotics.

Determination of fluoroquinolones illegally added in traditional prostate medicines by ultrasonic-assisted dispersive liquid liquid micro-extraction based on deep eutectic solvent combined with quantitative 19F nuclear magnetic resonance method

We optimized the combination of deep eutectic solvent (DES)-based ultrasonic-assisted dispersive liquid-liquid microextraction method and 19F qNMR for quantitation of 5 kinds of fluoroquinolone antibiotics illegally added to drugs for prostatitis treatments (Ciprofloxacin, Levofloxacin, Sparfloxacin, Gatifloxacin, Enrofloxacin). In this study, methyltrioctylammonium bromide and n-capric acid were mixed at a 2:1 M ratio to prepare hydrophobic DES. The newly prepared DES was used as the extract. Fluoroquinolone antibiotics were extracted from saturated ammonium sulfate solution and detected by 19F qNMR. In this study, the effects of extraction conditions such as DES volume, salt dosage, ultrasonic time, centrifugal time, and vortex time on extraction efficiency were systematically investigated. Under the optimal conditions, good linearity (correlation coefficient r: 0.9993–0.9998) was obtained with a detection limit of 0.1 μg mL−1. The extraction reproducibility (RSD) of intra-day and inter-day were below 5.01 and 5.98%, respectively. This study showed feasibility of detection of fluoroquinolone antibiotics illegally added in traditional medicines for prostatitis treatments by DES-based ultrasonic-assisted dispersion-liquid microextraction combined with 19F qNMR method.

Hydrophobic deep eutectic solvent-based ultrasonic-assisted dispersive liquid-liquid microextraction for preconcentration and determination of trace cadmium and arsenic in wine samples

In present study, DL-lactic acid/trioctylmethylammonium chloride-based deep eutectic solvent (DES), which was considered as an environmental friendly extraction solvent to replace traditional organic reagent, was firstly presented for monitoring of trace cadmium (Cd) and arsenic (As) in wine samples by ultrasonic-assisted dispersive liquid-liquid microextraction (UA-DLLME) method. Moreover, different extraction conditions, including the type and volume of DES and dispersive solvent, pH of the solution, salt amount, time of vortex and sonication, were systematically evaluated. At the optimized extraction conditions, good linear relationships (0.50–8.0 μg·L−1 for Cd, 2.0–50 μg·L−1 for As) were obtained and limits of detection of Cd and As were 0.080 and 0.30 μg·L−1, respectively. In addition, the accuracy (as recoveries %), and intra-/inter-day precision (as relative standard deviation %) were in the ranges of 90.6–103.6% and 2.9–4.5%, respectively. Finally, the proposed method was applied to analyze 6 kinds of wine samples, which possessed wide practical application value in monitoring heavy metal residues in wine and even complex food matrices.

Ultrasound-assisted dispersive liquid-liquid microextraction for determination of enrofloxacin in surface waters

This work describes the development of an HPLC-FLD methodology for the separation of five fluoroquinolones (ciprofloxacin, enrofloxacin, sarafloxacin, norfloxacin and levofloxacin) followed by optimization of the DLLME process for the clean-up and preconcentration of enrofloxacin in samples of seawater and river water. The mobile phase used for the chromatographic separation consisted of methanol: phosphate buffer (NaHPO4 H2O 0.04 M pH 3 with H3PO4 85%), gradient eluted at a ratio of 20:80 (v:v). The mobile phase flow was maintained at 1.2 mL min−1. For the ultrasonic-assisted dispersive liquid-liquid microextraction (UA-DLLME), the following conditions were used: 8 mL of sample with pH adjusted to 8, extraction solvent: 500 μL of chloroform, dispersive solvent: 500 μL of acetonitrile; samples were vortexed and sonicated for 2 min, each. The enrichment factor (EF) was 54.7 and the recovery was 70%, achieving a limit of detection (LOD) of 0.11 µg L−1. Repeatability and intermediate reproducibility presented values of relative standard deviation (RSD) lower than 2%. Finally, the optimized method was applied to the analysis of water and enrofloxacin was detected in both water samples with a concentration of 0.20 µg L−1 in the river and 0.12 µg L−1 in the seawater. However, recovery tests performed to evaluate the water matrices' effects on the extraction performance, presented recoveries of 72 ± 6.1 for river water and 27 ± 8.3 for seawater. These results demonstrate that hereby developed method is only suitable for water samples with a low salinity content.

Ultrasonic assisted dispersive liquid-liquid microextraction combined with flame atomic absorption spectrometry for determination of trace gallium in vanadium titanium magnetite

A new method of ultrasonic assisted dispersive liquid-liquid microextraction (USADLLME) combined with flame atomic absorption spectrometry (FAAS) was developed to determinate trace gallium in vanadium titanium magnetite. In the proposed approach, 1-(2-pyridineazo)-2-naphthol was selected as a complexant of gallium and chlorobenzene was chosen as extractant. The processes of complex formation and microextraction were influenced by the following factors: dosage of complexant, complex pH, extractant and its dosage, extraction temperature and time, etc. Under optimal conditions, the linear range of working curve was 0.1–1 μg/mL with detection limit of 0.07 μg/mL, and the enrichment factor of gallium was 124. 0.5 μg/mL gallium standard solution was parallelly extracted using USADLLME and determined by FAAS for 7 times and the relative standard deviation (RSD) was 13.54%. The presented method was simple, fast, sensitive and low cost, which had been successfully applied to the quantitative determination of gallium in vanadium titanium magnetite with complex matrix.

Ultrasonication Assisted Dispersive Liquid-liquid Micro Extraction (USA-DLLME) for Determination of Pyrene Concentration in Water

Pyrene is one of the chemical compounds of polycyclic aromatic hydrocarbons (PAHs) that has been reported as toxic, carcinogenic, and mutagenic which commonly found in water, food, soil, and air. Therefore, a study of ultrasonic assisted dispersive liquid-liquid microextraction (USA-DLLME) was conducted to extract pyrene from polluted water. The analytical parameters such as volume of extractant solvent, volume of disperser solvent, sonication time, and centrifugation speed were optimized using response surface method (RSM). Gas chromatography-flame ionization detector was used to analyse the pyrene content. The extraction recovery obtained for validation on real water based on optimization are in the range of 14.8%-49.8%. The low value of extraction recovery must be due to unsuitable types of extraction solvent used. However, this study have achieved all the objectives based on the developed method.

Rapid Multi-Residue Analysis of Herbicides with Endocrine-Disrupting Properties in Environmental Water Samples Using Ultrasound-Assisted Dispersive Liquid–Liquid Microextraction and Gas Chromatography–Mass Spectrometry

A highly efficient ultrasonic-assisted dispersive liquid–liquid microextraction (UA-DLLME) procedure coupled with gas chromatography–mass spectrometry was developed for simultaneous analysis of multiclass herbicides with endocrine-disrupting properties in environmental water samples. The parameters affecting the method’s extraction efficiency, such as the types and volumes of the extractant and dispersive solvents, sample pH, and salt concentration, were systematically optimized by response surface methodology based on central composite design to achieve excellent recoveries for multiclass herbicides. The final UA-DLLME protocol involved 115.6 µL of chloroform (extractant), 861.5 µL of ethanol (dispersive solvent), 5.0 mL of water samples, pH 10.0, and 4.3% NaCl solution. The performance of the developed UA-DLLME was compared with that of conventional solid-phase extraction (SPE). Under optimal extraction conditions, UA-DLLME exhibited a higher enrichment factor and greater sensitivity than SPE, with limits of detection and limits of quantification of 0.004–0.024 and 0.013–0.079 µg L−1, respectively, for seawater samples. The accuracy and precision of UA-DLLME were satisfactory for seawater samples spiked at three levels (0.2, 2.5, and 5.0 µg L−1). Average recoveries ranging from 82.3 to 101.8% were achieved, with relative standard deviations lower than 12.8%. The proposed analytical method was successfully applied to the simultaneous determination and quantification of 17 herbicides in environmental river and seawater samples.

Sensitive and rapid determination of pyrethroids in human blood by gas chromatography-tandem mass spectrometry with ultrasound-assisted dispersive liquid-liquid microextraction.

In this study, a sensitive and fast procedure of ultrasonic-assisted dispersive liquid-liquid microextraction (UADLLME) coupled with gas chromatography-tandem mass spectrometry (GC-MS/MS) for the determination of major pyrethroid pesticides (permethrin, tetramethrin, bifenthrin, fenvalerate, flucythrinate, fluvalinate, fenpropathrin, deltamethrin, and cyhalothrin) in blood samples was developed. Response surface methodology (RSM) combined with Box-Behnken design (BBD) and ANOVA function was used to optimize key factors affecting the extraction efficiency of UADLLME procedure. Target compounds were analyzed by GC-MS/MS. Under the optimal conditions, good linearity (R2 >0.99) was achieved for all the analytes in the concentration range of 0.5 to 100μg L-1 . The recoveries for spiked samples at 3 concentration levels were between 70.2 and 91.8%, with relative standard deviations (RSD) lower than 10%. Very low limits of detection (LODs) and limits of quantification (LOQs) ranging from 0.01 to 0.1μg L-1 and from 0.03 to 0.3μg L-1 were achieved. This method was successfully applied to the determination of low concentration of pyrethroids in blood samples from real forensic cases. High sensitivity, fast determination, simplicity in operation, small sample volume, and low usage of organic solvents are the advantages of this method. This methodology is of important value for sensitive and quick determination of residue pesticides and metabolites, study of residue pesticides behavior in human body, as well as application in real forensic cases.

Combination of microwave-assisted extraction and ultrasonic-assisted dispersive liquid-liquid microextraction for separation and enrichment of pyrethroids residues in Litchi fruit prior to HPLC determination

A novel method for simultaneous determination of pyrethroids residues in Litchi fruit has been developed by HPLC-UV detection using microwave-assisted extraction (MAE) coupled with ultrasonic-assisted dispersive liquid-liquid microextraction (UADLLME). Extraction conditions of MAE and UADLLME were respectively investigated by single-factor experiments and response surface methodology. Optimized experimental conditions included 310μL of chlorobenzene as extraction solvent, 1.3mL of ethanol as dispersive solvent and 3min of extraction time for UADLLME. In the case of MAE, extraction temperature of 70°C, extraction time of 4min and solvent-to-materials ratio of 40:1 were adopted. Results demonstrated that the proposed method had good performance with linearity of 0.0050–4.98mg/L, recovery of 83.3–91.5%, RSDs below 5.6% and detection limit (LOD) of 1.15–2.46μg/L for six pyrethroids, offering higher extraction efficiency and larger enrichment factor. MAE-UADLLME provided a sensitive and efficient alternative to determination of trace amounts of pesticides residues in food samples.

Sensitive determination of cholesterol and its metabolic steroid hormones by UHPLC-MS/MS via derivatization coupled with dual ultrasonic-assisted dispersive liquid-liquid microextraction.

Quantitative analysis of cholesterol and its metabolic steroid hormones plays a vital role in diagnosing endocrine disorders and understanding disease progression, as well as in clinical medicine studies. Because of their extremely low abundance in body fluids, it remains a challenging task to develop a sensitive detection method. A hyphenated technique of dual ultrasonic-assisted dispersive liquid-liquid microextraction (dual-UADLLME) coupled with microwave-assisted derivatization (MAD) was proposed for cleansing, enrichment and sensitivity enhancement. 4'-Carboxy-substituted rosamine (CSR) was synthesized and used as derivatization reagent. An ultra-high performance liquid chromatography tandem mass spectrometry (UHPLC-MS/MS) method was developed for determination of cholesterol and its metabolic steroid hormones in the multiple reaction monitoring mode. Parameters of dual-UADLLME, MAD and UHPLC-MS/MS were all optimized. Satisfactory linearity, recovery, repeatability, accuracy and precision, absence of matrix effect and extremely low limits of detection (LODs, 0.08-0.15pgmL(-1) ) were achieved. Through the combination of dual-UADLLME and MAD, a determination method for cholesterol and its metabolic steroid hormones in human plasma, serum and urine samples was developed and validated with high sensitivity, selectivity, accuracy and perfect matrix effect results. Copyright © 2016 John Wiley & Sons, Ltd.

Highly efficient and sensitive screening of ractopamine in foodstuffs by HPLC-FLD using fluorescent labeling and ultrasonic-assisted dispersive liquid–liquid microextraction

A new analytical method for ractopamine (RAC) screening in foodstuffs was established based on fluorescent labeling coupled with ultrasonic-assisted dispersive liquid–liquid microextraction (UA-DLLME).

Determination of L-dopa and dopamine in rat brain microdialysate by ultra high performance liquid chromatography-tandem mass spectrometry using stable isotope-coded derivatization coupled with dispersive liquid-liquid microextraction

The sensitive detection method of levodopa (L-DOPA) and dopamine (DA) in rat brain microdialysate of Parkinson's disease (PD) is an essential tool for the clinical study and attenuated synergistic drug screening for L-DOPA from traditional Chinese medicines. Using d0/d3-10-methyl-acridone-2-sulfonyl chloride (d0/d3-MASC) as stable isotope derivatization reagent, a novel ultra high performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) method was developed and validated for L-DOPA and DA by stable isotope- coded derivatization coupled with ultrasonic-assisted dispersive liquid-liquid microextraction (UA-DLLME). d3-MASC (light) and d3-MASC (heavy) were used as derivatization reagents for microdialysate samples and standards, respectively. Mixtures of the two solutions were prepared by UA-DLLME for UHPLC-MS/MS analysis with multiple reaction monitoring (MRM) mode. With d3-MASC heavy derivatives as internal standards for corresponding light derivatives from samples, the stable isotope internal standard quantification for L-DOPA and DA was carried out. The stable derivatives were obtained in aqueous acetonitrile (pH 10.8 sodium carbonate-sodium bicarbonate buffer) at 37 °C for 3.0 min, and then were separated within 2.0 min using gradient elution. Linear range was 0.20-1500.0 nmol/L (R > 0.994). LODs were 0.005 and 0.009 nmol/L for DA and L-DOPA (S/N = 3), respectively. This method was validated, and it showed obvious advantages in comparing with the reported methods in terms of sensitivity, analysis speed and anti-matrix interference. This method has been successfully applied to the study of effect of Shouwu Fang on L-DOPA and DA concentration fluctuations in PD rat brain microdialysate.

Sensitive Determination of Panaxadiol Using Rhodamine B as Sensitizing Derivatization Reagent by Ultrahigh Performance Liquid Chromatography Triple Quadrupole Mass Spectrometry

Commercial Rhodamine B was first reported as a derivatization reagent labeling hydroxyl compound for mass spectrometry sensitization. In virtue of the strategy of ultrasonic-assisted dispersive liquid-liquid microextraction (UA-DLLME) combined with Rhodamine B derivatization, a new method of ultrahigh performance liquid chromatography triple quadrupole mass spectrometry (UHPLC-MS/MS) was developed for the sensitive determination of Panaxadiol (PD). UA-DLLME and derivatization conditions were investigated. PD in cosmetics and ginseng was extracted by UA-DLLME (150 mu L chloroform as extraction solvent, 500 mu L ethanol as disperser solvent, 3 min). Using Rhodamine B as precolumn derivatization reagent, the stable derivative of PD was obtained in acetonitrile at 70 degrees C for 30 min under microwave radiation (800 W) with the catalyst of N, N'-carbonyldiimidazole (CDI) and 4-dimethylaminopyridine (DMAP). And then the PD derivative was separated and detected within 3 min by multiple reaction monitoring (MRM) mode of UHPLC-MS/MS. The LOD was 4.0 ng L-1, and the LOQ was 15.0 ng L-1. This method had perfect linearity, precision and recovery results, and showed obvious advantages such as sensitivity and low matrix effect in comparison with the previously reported methods.

Development of an Efficient HPLC Fluorescence Detection Method for Brassinolide by Ultrasonic-Assisted Dispersive Liquid–Liquid Microextraction Coupled with Derivatization

A novel hyphenated technique based on ultrasonic-assisted dispersive liquid–liquid microextraction (UA-DLLME) coupled with derivatization has been established for the determination of brassinolide (BL, a representative of brassinosteroids) by HPLC fluorescence detection. 9-Phenanthreneboronic acid is used as labeling reagent of BL. UA-DLLME parameters containing type and volume of extraction and disperser solvent, pH and ultrasonication time are optimized. Derivatization parameters are optimized included amount of 9-phenanthreneboronic acid, volume ratio of pyridine, derivatization time and temperature. Under optimal conditions, quantitative linear range of BL is 50–1,000 ng L−1 and excellent linear response is observed with correlation coefficient of 0.9996. Limit of detection and limit of quantification are calculated as 8.0 and 25.0 ng L−1, respectively. RSDs of retention time and peak area are in the range of 0.68–0.97 % and 4.61–6.54 % for intra-day precision, 1.32–1.94 % and 7.28–9.75 % for inter-day precision, respectively. Accuracy is satisfactory in the range of 82.3–125.1 %. RSDs’ values of repeatability are in the range of 0.82–1.79 and 3.95–8.53 % for retention time and peak area, respectively. Enrichment factor for BL is 189. The results of recovery and matrix effect are in the range of 82.0–108.6 and 90.0–115.3 %, respectively. The proposed method has been applied for the determination of BL in Arabidopsis thaliana, Daucus carota and Brassica campestris L. leaves with much higher sensitivity than many other methods.