Volume Of Extraction Solvent Research Articles

Implementation of multicriteria decision analysis in design of experiment for dispersive liquid-liquid microextraction optimization for chlorophenols determination

A novel and efficient approach to optimization of extraction step prior the chromatographic determination of nine chlorinated phenols is described. It is based on the combination of design of experiments and multicriteria decision analysis. Such an approach is used to optimize dispersive liquid-liquid microextraction procedure for the determination of 9 chlorophenols in water samples. Three parameters are optimized – sample volume, volume of disperser solvent and extraction solvent. Combination of the technique for order of preference by similarity to ideal solution with central composite design allows to perform multi-analyte procedure optimization. It gives information about the efficiency of the system for every experimental plan point in terms of closeness to ideal solution. The optimal conditions for extraction of chlorophenols are 76 μL of extraction solvent, 0.6 mL of dispersive solvent and 6.7 mL of water sample. The presented approach has the potential to be applied in variety of optimization systems.

Method for the simultaneous determination of monoaromatic and polycyclic aromatic hydrocarbons in industrial effluents using dispersive liquid-liquid microextraction with gas chromatography-mass spectrometry.

We present a new method for simultaneous determination of 22 monoaromatic and polycyclic aromatic hydrocarbons in postoxidative effluents from the production of petroleum bitumen using dispersive liquid-liquid microextraction coupled to gas chromatography and mass spectrometry. The eight extraction parameters including the type and volume of extraction and disperser solvent, pH, salting out effect, extraction, and centrifugation time were optimized. The low detection limit ranging from 0.36 to 28μg/L, limit of quantitation (1.1-84μg/L), good reproducibility, and wide linear ranges, as well as the recoveries ranging from 71.74 to 114.67% revealed that the new method allows the determination of aromatic hydrocarbons at low concentration levels in industrial effluents having a very complex composition. The developed method was applied to the determination of content of mono- and polycyclic aromatic hydrocarbons in samples of raw postoxidative effluents in which 15 compounds were identified at concentrations ranging from 1.21 to 1017.0μg/L as well as in effluents after chemical treatment.

Determination of Benzotriazole and Its Derivatives in Aqueous Sample with Air-assisted Liquid-Liquid Microextraction Followed by High-performance Liquid Chromatography

Abstract Benzotriazole and its derivatives are persistent contaminants and ubiquitous in aquatic environments. Here, a simple, reliable method based on air-assisted liquid-liquid microextraction coupled with high-performance liquid chromatography with a UV detector for determining 1H-benzotriazole, 5-methyl-1H-benzotriazole and 5-chloro-1H-benzotriazole in aqueous samples was developed. In this procedure, the analytes quickly entered into the extraction solvent via the bolus flow formed during the movement of the plunger without disperser solvent. 1-Hexanol was used as the extractant, thus avoiding chlorinated solvents, and a narrow-neck tube with round bottom was self-made to facilitate collection of the low-density extract phase and centrifugation at high speed. Those main parameters, including sample volume, type and volume of extraction solvent, number of suction-injection cycle, salt addition, and the pH were optimized. Under the optimized conditions, the pretreatment could be completed within two minutes with a good linearity (r > 0.9996). Satisfactory intra-day (3.0%–4.3%, n = 5) and inter-day (5.9%–7.8%, n = 5) precisions were observed. Further, the method was applied in analysis of real samples including tap water, lake water, river water, and municipal waste water with good recoveries (73%−116%).

Optimization of a modified QuEChERS method for the determination of tetracyclines in fish muscle by UHPLC–MS/MS

In this work a sample treatment based on a modified QuEChERS method combined with ultra-high-performance liquid chromatography–tandem mass spectrometry (UHPLC–MS/MS) was proposed to determine the residues of five common tetracyclines in fish muscle samples. The separation was achieved in less than 4 min and the analytes were detected in electrospray ionization in positive mode (ESI+) with multiple reaction monitoring mode. Parameters affecting the extraction step, such as the amount of sample and EDTA-McIlvaine buffer and extraction solvent volumes, were optimized by means of experimental design. In order to obtain the lowest matrix effect, parameters affecting the clean-up step by dispersive solid phase extraction (dSPE), were also studied. Under optimum conditions, matrix effect was lower than │15│% in all cases. Limits of quantification were lower than 4.4 μg kg−1 for the compounds in the selected samples, being in compliance with the current legislation. The precision, expressed as relative standard deviation, was below 18.5% and the recoveries for fortified fish samples (salmon and panga) higher than 80%. These results revealed that the proposed method is simple, rapid, cheap and environmentally friendly, being successfully applicable for the determination of these residues in fish samples.

Determination of cobalt by air-assisted liquid–liquid microextraction

A rapid and selective technique for extraction, preconcentration and determination of trace amounts of cobalt in water and pharmaceutical samples by air-assisted liquid–liquid microextraction combined with flame atomic absorption spectrometry is proposed. 1-Nitroso-2-naphthol is used as a complexing agent and 1-octanol as an extraction solvent. Parameters relevant for analytical effectivity, i.e. pH of sample solution, concentration of complexing agent, volume of extraction solvent, and number of extraction cycles are optimized using a Box–Behnken design. At optimum conditions, a dynamic linear range of 5–600 µg L−1 is obtained, with a limit of detection of 1.2 µg L−1. The method is used for determination of Co(II) in environmental water and pharmaceutical samples.

Extraction and Determination of Trace Amounts of p-Coumaric Acid in Vinegar, Carrot Juice, and Seed Extract from Silybum marianum (L.) Gaertn.

In this study, for the monitoring and quantification of p-coumaric acid (p-CA) in vinegar, carrot juice, and seed extract from the plant species Silybum marianum (L.) Gaertn, an efficient and low-cost analytical method has been applied. For this purpose, a dispersive liquid-liquid microextraction (DLLME) method, followed by UV-Vis spectrophotometric detection, was used. To form a cloudy solution, a binary mixture containing ethanol as a disperser solvent and chloroform as an extraction solvent was rapidly injected by syringe into a sample solution containing p-CA. After centrifugation, dilution of the obtained organic phase was done with the proper amount of ethanol, and the phase was transferred into a micro cell for subsequent measurement. Some effective parameters for the DLLME method, such as the volume of disperser solvent and extraction solvent, pH, and salt concentration were inspected by a 24 full factorial central composite design using design Export Software. Under the optimized conditions, linearity was between 10 and 150 ng/mL, and the LOD was 2.3 ng/mL. The results of the proposed method were similar to the obtained results using a GC with flame-ionization detection method.

Dispersive liquid–liquid microextraction using the freezed floating organic drop for rapid, fast, and sensitive determination of lead

ABSTRACTA rapid, simple, and sensitive method was developed for lead preconcentration and separation in various real samples by dispersive liquid–liquid microextraction based on the freezing of floating organic drop. In this method, a suitable extraction solvent dissolved in a dispersive solvent was quickly syringed into the water sample so that the solution became turbid. Then, two phases were separated by centrifugation. The floating extractant droplet can be easily solidified on an ice bath and taken out of the water sample. Then, it can be liquefied instantly at room temperature, and analyte can be determined in it. In the creation of a hydrophobic complex with lead, 1-(2-pyridylazo)-2-naphthole (PAN) was used as the chelating agent. 1-Undecanol and acetone were used as extraction and disperser solvent. To achieve the highest recovery, some factors (type and volume of dispersive and extraction solvent, pH, PAN concentration, and salt concentration) were optimised. Under optimised conditions (pH = 9, 1.0 × 10–3 mol L−1 PAN, 15% w/v NaCl, 100 µL 1-undecanol, and 0.3 mL acetone), the lead calibration graph was linear from 1.5 to 80 μg L−1. The detection limit and preconcentration factor were 0.5 μg L−1 and 50, respectively. Lead was successfully determined in water and food (spinach, rice, potato, carrot, and black tea bag) samples by this method.

Homogeneous liquid-liquid microextraction via flotation assistance coupled with gas chromatography-mass spectrometry for determination of myclobutanil in cucumber, tomato, grape, and strawberry using genetic algorithm

ABSTRACTFacile and potent homogeneous liquid–liquid microextraction via flotation assistance method (HLLME-FA) combined with gas chromatography-mass spectrometry was proposed for determination of trace amounts of myclobutanil in fruit and vegetable samples. The paramount parameters, such as extraction and homogeneous solvent types and volumes, ionic strength and extraction time were studied. Under optimum conditions, the detection limit of 0.005 ng g−1, the linear range of 0.05–100 ng g−1, and the precision of 3.8% were acquired. A three-layer artificial neural network (ANN) model was used with 10 neurons and tan-sigmoid function at hidden layer and a linear transfer function at output layer were developed to predict the process. The results indicated that the proposed ANN model could perfectly predict the process with the mean square error of 0.89%. Then genetic algorithm was utilised to optimise the parameters. The proposed procedure showed satisfactory results for analysis of cucumber, tomato, grape, and strawberry.

Saturation reduces in-vitro leakage of monomers from composites

ObjectiveAccurate knowledge of the quantity of released monomers from composites is important. To evaluate the elution of monomers, polymerized composites are typically immersed in an extraction solvent. The objective was to determine whether the volume of extraction solvent and the immersion time influences monomer leachability from dental composite materials. MethodsComposite disks of two commercial composites, (Filtek Supreme XTE, 3M ESPE and G-aenial Universal Flo, GC) were prepared. The disks (n=10) were placed in a glass vial with 1ml, 2ml or 3ml of extraction solvent (100% ethanol with deuterated diethylphalate as internal standard). After either 7 or 30 days at 37°C, the supernatant was collected and the amount of released monomers (BisEMA, BisGMA, UDMA, TEGDMA) and bisphenol A was measured with liquid chromatography mass spectroscopy. ResultsFor both tested composites, the highest amount of released monomers was measured after sample incubation in 3ml, while the lowest amount was measured in 1ml of extraction solvent. Furthermore, 30 days did not result in much more monomer release compared to 7 days, and for most monomers, there was no statistically significant difference in release between 7 and 30 days. SignificanceRelease kinetics in in-vitro experiments are also influenced by saturation of the extraction solvent with the leached monomers. This is important as it is unlikely that saturation can be reached in an in-vivo situation, where saliva (or pulpal fluid) is continuously refreshed. Saturation of the extraction solvent can be avoided in-vitro by refreshing the extraction medium after equal time intervals.

Application of solvent floatation to separation and determination of triazine herbicides in honey by high-performance liquid chromatography.

Based on the foaming property of the honey, a rapid, simple, and effective method solvent floatation (SF) was developed and firstly applied to the extraction and separation of triazine herbicides in honey. The analytes were determined by high-performance liquid chromatography. Some parameters affecting the extraction efficiencies, such as the type and volume of extraction solvent, type of salt, amount of (NH4)2SO4, pH value of sample solution, gas flow rate, and floatation time, were investigated and optimized. The limits of detection for analytes are in the range of 0.16-0.56μgkg-1. The recoveries and relative standard deviations for determining triazines in five real honey samples are in the range of 78.2-112.9 and 0.2-9.2%, respectively.

Development of a preconcentration method for indomethacin in natural waters using dispersive liquid–liquid microextraction based on solidification of floating organic drop technique

Abstract A new dispersive liquid–liquid microextraction method based on the solidification of a floating organic drop was developed for the preconcentration of indomethacin in natural waters followed by ultraviolet-visible (UV-Vis) spectrophotometric detection. 1-undecanol and ethanol were used as the extraction solvent and the disperser solvent, respectively. An investigation of the main experimental parameters that may affect the extraction efficiency, such as sample pH, volume of extraction and disperser solvents, sodium chloride concentration and centrifugation time was undertaken. The effect of interfering ions on the recovery of indomethacin was also examined. Under optimal conditions without any preconcentration, the limit of detection was 17.9 μg/L calculated from LOD = 3 Sb/m and was also calculated as 74.9 μg/L from the regression values of the calibration line using 3.19 Se/m. The proposed preconcentration method was successfully applied to determination of indomethacin in spiked tap water and river water samples. The recovery values for spikes added to water samples were between 94.5 and 103.0%.

Determination of Vitamin B6, B9 and B12 in Halophytes by Solid Phase Extraction Followed by HPLC-UV

In this work, solid phase extraction (SPE) was proposed for simultaneous determination of trace levels of vitamin B-6, B-9 and B-12. High performance liquid chromatography with UV detection (HPLC-UV) was used. The experimental conditions including pH of sample and type and volume of extraction solvent were studied by one-factor-at-a time method. The limit of detection in the optimal conditions was 14.91, 10.03, and 7.25 ngkg(-1) for vitamins B-6, B-9 and B-12 respectively and relative standard deviations (RSD) of the analysis less than 8 (n=3). Recoveries of vitamins B-6, B-9 and B-12 were in the ranges of 80-93. The proposed method was successfully applied for the simultaneous determination of vitamin B-6, B-9 and B-12 in halophyte samples such as, Salicornia, Suaeda monoica, Suaeda aegyptiaca, Sueada vera and Sueada martima.

Simultaneous Determination of Bismuth, Lead, and Iron in Water Samples by Optimization of USAEME and ICP–OES via Experimental Design

Ultrasound-assisted emulsification–microextraction followed by inductively coupled plasma–optical emission spectrometry was utilized for simultaneous pre-concentration and trace detection of lead, bismuth, and iron in water samples. Disodium N,N $$^\prime$$ -bis(salicylidene)ethylenediamine and trichloroethylene were used as chelating agent and extraction solvent, respectively. The parameters of interest were volume of extraction solvent, temperature, and concentrations of salt and chelating agent. A fractional factorial design was developed to identify these parameters and how they vary with one another. The results demonstrated that the concentrations of salt and chelating agent affected extraction efficiency. Subsequently, a central-composite design was used to acquire optimum levels of effective parameters. The optimal conditions were 160.7 mg L $$^{-1}$$ and 1.77% (w/v) for concentration of chelating agent and salt, respectively. The linear dynamic ranges were determined to be 1–1000 $$\upmu$$ g L $$^{-1}$$ for Pb and Bi, and 10–1000 $$\upmu$$ g L $$^{-1}$$ for Fe. The correlation coefficient ( $$R^2$$ ) was 0.990–0.995. The limits of detection were 0.54–0.78 $$\upmu$$ g L $$^{-1}$$ . The relative standard deviation (concentration $$=$$ 200 $$\upmu$$ g L $$^{-1}$$ , $$n = 8$$ ) was in the range of 2.0–4.3%. This method was successfully applied for the trace detection of Pb, Bi, and Fe in freshwater samples of waterfall and spring and satisfactory relative recoveries (96.2–99.6%) were obtained.

Determination of 18 polychlorinated biphenyls in tea by gas chromatography-mass spectrometry coupled with dispersive solid-phase extraction

A method for the rapid determination of 18 polychlorinated biphenyls (PCBs) in tea by gas chromatography-mass spectrometry (GC-MS) coupled with dispersive solid-phase extraction (dSPE) was developed and evaluated. Carboxylated multi-walled carbon nanotubes (MWCNTs-COOH) and primary secondary amine (PSA) were used as sorbents in pretreatment process. PCBs were ultrasonically extracted from tea samples with hexane-acetone (1:1, v/v), and purified with the mixed sorbents of MWCNTs-COOH and PSA after replacing hexane-acetone by toluene. The PCBs were determined by an electron impact ionization source and selected ion monitoring mode. The analytes were qualitatively confirmed from the retention time and relative abundance ratio of characteristic ions, and quantified by a matrix-matched standard solution. The chromatographic and MS parameters influencing separation and sensitivity were optimized, and major factors affecting the extraction and cleanup efficiency including type and volume of extraction solvent, extraction time, type and amount of cleanup sorbent, and clean-up time were investigated. The performance of the method was evaluated. Under optimum conditions, satisfactory linear relationship was observed with the content of PCBs ranging from 5 to 500 μg/kg, with correlation coefficients (r) no less than 0.9998. The 18 PCBs in three kinds of tea matrices including Biluochun tea, Tieguanyin tea and Pu'er tea were spiked at 5, 10 and 100 μg/kg to evaluate recoveries, which ranged from 90.7% to 115.2% with relative standard deviations (n=5) between 0.3% and 10.9%. The limits of detection and the limits of quantification were 0.3-1.7 μg/kg and 5 μg/kg for each PCB, respectively. The method is simple, rapid, accurate, sensitive and effective, and is suitable for the determination of the 18 PCBs in different kinds of tea.

Rat Fecal Metabolomics-Based Analysis.

Fecal metabolomics-based analysis indisputably constitutes a very useful tool for elucidating the biochemistry of digestion and absorption of the gastrointestinal system. Fecal samples represent the most suitable, non-invasive, specimen for the study of the symbiotic relationship between the host and the intestinal microbiota.It is well established that the balance of the intestinal microbiota changes in response to some stimuli, physiological such as gender, age, diet, exercise and pathological such as gastrointestinal and hepatic disease. Fecal samples have been analyzed using the most widespread analytical techniques, namely, NMR spectroscopy, GC-MS, and LC-MS/MS. Rat fecal sample is a frequently used and particularly useful substrate for metabolomics-based studies in related fields. The complexity and diversity of the nature of fecal samples require careful and skillful handling for the effective quantitative extraction of the metabolites while avoiding their deterioration. Parameters such as the fecal sample weight to extraction solvent volume, the nature and the pH value of the extraction solvent, and the homogenization process are some important factors for the optimal extraction of samples, in order to obtain high-quality metabolic fingerprints, using either untargeted or targeted metabolomics.

Antifouling booster biocide extraction from marine sediments: a fast and simple method based on vortex-assisted matrix solid-phase extraction.

This paper reports the development of an analytical method employing vortex-assisted matrix solid-phase dispersion (MSPD) for the extraction of diuron, Irgarol 1051, TCMTB (2-thiocyanomethylthiobenzothiazole), DCOIT (4,5-dichloro-2-n-octyl-3-(2H)-isothiazolin-3-one), and dichlofluanid from sediment samples. Separation and determination were performed by liquid chromatography tandem-mass spectrometry. Important MSPD parameters, such as sample mass, mass of C18, and type and volume of extraction solvent, were investigated by response surface methodology. Quantitative recoveries were obtained with 2.0g of sediment sample, 0.25g of C18 as the solid support, and 10mL of methanol as the extraction solvent. The MSPD method was suitable for the extraction and determination of antifouling biocides in sediment samples, with recoveries between 61 and 103% and a relative standard deviation lower than 19%. Limits of quantification between 0.5 and 5ngg-1 were obtained. Vortex-assisted MPSD was shown to be fast and easy to use, with the advantages of low cost and reduced solvent consumption compared to the commonly employed techniques for the extraction of booster biocides from sediment samples. Finally, the developed method was applied to real samples. Results revealed that the developed extraction method is effective and simple, thus allowing the determination of biocides in sediment samples.

Optimization of Solvent Terminated Dispersive Liquid-Liquid Microextraction of Copper Ions in Water and Food Samples Using Artificial Neural Networks Coupled Bees Algorithm.

A multivariate method based on solvent terminated dispersive liquid-liquid microextraction was developed for the determination of Cu2+ ions in aqueous samples. In the proposed approach, di-2-ethylhexylphosphoric acid, xylene and acetone were used as chelating agent, dispersive and extraction solvents, respectively. The effects of various factors on the extraction efficiency such as extraction and dispersive solvent volumes, salt addition and pH were studied using central composite design (CCD) and artificial neural networks coupled bees algorithm (ANN-BA). Upon comparison of these techniques, ANN-BA model was considered to be better optimization method due to its higher percentage relative recovery (about 5%) as compared to the CCD approach. The linear range and the limits of detection (S/N = 3) and quantitation (S/N = 10) were 0.22-140, 0.08 and 0.22µgL-1, respectively. Under the optimal conditions, the recoveries for real samples spiked with 0.1 and 0.3mgL-1 were in the range of 85-98%.

Determination of Fenpyroximate from Four Types of Honey by Liquid Chromatography/Tandem Mass Spectrometry

Fenpyroximate is an acaricide used to control phytophagous mites in beekeeping farms, and is used to regulate residual amounts in honey in European Union countries. An effective and accurate sample preparation method was established for a liquid chromatograph‐mass spectrometer/mass spectrometer (LC–MS/MS) analysis of four types of honey (acacia honey, wild honey, manuka, and chestnut honey). Experiments were carried out to determine the optimal values of parameters such as sample pH, type of solid‐phase cartridge, type and volume of extraction solvent, loading sample volume, type and volume of eluent for effective sample extraction, purification, and concentration. Chromatographic separation was performed using a C18 (3.0 mm i.d. × 50 mm length, 2.7 μm particle size) column under isocratic conditions of water and acetonitrile (30:70). The optimized parameters for the extraction of fenpyroximate are as follows: sample pH, 7; type of sorbent solid phase, aminopropyl; volume of extraction solvent, 20 mL; volume of loading sample, 2 mL; eluent, dichloromethane/n‐hexane (65/35%, v/v); eluent volume, 6 mL. The limits of detection and quantitation for spiked honey samples were 1.56 and 5.00 μg/kg, respectively. Linear correlation coefficient (r) obtained from a concentration range 5.00–50.0 μg/kg was 0.9914–0.9977, while the accuracy and precision were 87.99–119.06% and 0.68–14.71% (RSD), respectively. Residue monitoring of fenpyroximate was also performed on 30 commercially available honeys using established methods.

Magnetic solid-phase extraction using MIL-101(Cr)-based composite combined with dispersive liquid-liquid microextraction based on solidification of a floating organic droplet for the determination of pyrethroids in environmental water and tea samples

An efficient magnetic metal-organic framework (MOF) material MIL-101(Cr)-based composite (MIL, Matérial Institute Lavoisier) was applied as a sorbent for magnetic solid phase extraction (MSPE) coupled with dispersive liquid-liquid microextraction based on the solidification of floating organic drop (DLLME-SFO) method of trace pyrethroids in environmental water and tea samples. Target analytes were quantified by gas chromatography-electron capture detection (GC-ECD). The variables influencing the performance of both steps, including amount of MIL-101(Cr)-based composite, pH value, ultrasound extraction time, elution solvent, elution/disperser solvent volume, elution time and extraction solvent volume, were systematically investigated. The characteristics of the analytical method were evaluated. A linearity range (r=0.9989–0.9997) was obtained in the range of 0.05–10.0ng/mL. Excellent sensitivity levels were achieved with the detection limits of 0.008–0.015ng/mL and the quantitation limits of 0.028–0.050ng/mL. Under optimal conditions, the method was successfully established for the determination of pyrethroids in real samples with satisfactory recoveries ranging from 78.3–103.6%. Overall, the encouraging method exhibited the advantages of remarkable sensitivity, ease of operation, rapidity, low cost and environmental friendliness.

Modified dispersive liquid-phase microextraction based on sequential injection solidified floating organic drop combined with HPLC for the determination of phenobarbital and phenytoin.

A modified dispersive liquid phase microextraction based on sequential injection solidified floating organic drop was developed for simultaneous separation/preconcentration of trace amounts of phenobarbital and phenytoin. The important factors affecting on the extraction recovery including pH, the volume of extraction solvent, ionic strength, and the number of injections were investigated and optimized by Box-Behnken design and desirability function. Under the optimum experimental conditions, the calibration graph was linear in the concentration range of 1.0-300.0μg/L (r2 =0.997) for phenobarbital and 2.0-400.0μg/L (r2 =0.996) for phenytoin. The limit of detection and limit of quantification were 0.35 and 1.2μg/L for phenobarbital and 0.65 and 2.2μg/L for phenytoin, respectively. The relative standard deviation for six replicate determinations at 10μg/L was 3.3 and 4.1% for phenobarbital and phenytoin, respectively. The developed method was successfully applied to the determination of phenobarbital and phenytoin in urine and plasma samples.