An efficient, sensitive, and fast method was developed based on an ultrasound-assisted extraction followed by an ion-pair dispersiveliquid-liquidmicroextraction (USAE-IP-DLLME) for the simultaneous determination of five commonly used synthetic sulfonate dyes (tartarazine, quinoline yellow, sunset yellow, azorubine and brilliant blue) in ice cream samples using high performance liquid chromatography. First, important parameters on USAE and samples clean-up were investigated and optimized. Then, some effective parameters on DLLME were studied and optimized. Under the optimum conditions, good linearity (0.5-1000 µg l -1 , > r 2 = 0.99) were obtained for the dyes. Limits of detection and limits of quantization were in the range of 0.01-0.05 µg l -1 and 0.03-0.15 µg l -1 , respectively. The recoveries of the five synthetic colorants ranged from 90.3-109.7%. Intra (1.4-6.4%) and inter-day precision (3.9-9.7%) expressed as relative standard deviation (RSD) at 10 and 100 µg l -1 levels less than 10% were also achieved. Finally, this method was applied successfully in determination of the colorants in the ice cream samples.
A simple and rapid microextraction procedure based on dispersiveliquid-liquidmicroextraction (DLLME) was developed for determination and speciation of trace amounts of chromium (Cr) by flame atomic absorption spectrometry (FAAS). In the proposed approach, chloroform and methanol were used as extraction and dispersive solvents. A new Schiff's base ligand, bis(2-methoxy benzaldehyde) ethylene diimine was used as complexing agent. Effect of extraction solvent, disperser solvent, the volume of extraction and disperser solvent, pH of the aqueous solution and extraction time on extraction procedure were investigated and optimized. Under the optimum conditions, the calibration graph was linear in the range of 1-50 µg l -1 with a limit of detection of 0.7 µg l -1 . The relative standard deviation (RSD%) was 2.7% (n = 7) for Cr(III). The relative recoveries of spiked samples were between 98% and 102% and preconcentration factor (PF) was 20. The proposed method is a simple, fast, accurate, highly stable and selective and was applied for determination of chromium in milk and water samples with satisfactory results.
Immunoaffinity column clean up is, due to its selectivity, the most common pretreatment pro- cedure used for the analysis of OTA in differ- ent samples (Cicoňová et al. 2010; Fabiani et al. 2010; Kabak 2012). However, immunoaffin- ity columns cannot be reused (according to the manufacturer’s instructions) and are expensive. Dispersiveliquid–liquidmicroextraction (DLLME), introduced in 2006, is a simple, inexpensive, ef- ficient, and eco-friendly method (Rezaee et al. 2006). In DLLME methodology, an appropriate mixture of extraction and disperser solvents is injected into the aqueous sample containing the analytes and a cloudy solution (high turbulence) forms. In this step, the target analytes are rapidly transferred into fine droplets of the extraction solvent as a result of the enhanced surface area between two immiscible phases. The cloudy state is then centrifuged and the enriched droplets of extractant precipitate at the bottom of the conical test tube. The determination of the analytes can be performed by an appropriate analytical technique. DLLME has been widely used for the analysis of organic compounds (Melo et al. 2012; Zacharis et al. 2012; Karami-Osboo et al. 2013; Maham et al. 2013) and metal ions (Alexovič et al. 2012; Kocot et al. 2012).
DispersiveLiquidLiquidMicroExtraction (DLLME) is a novel liquid-liquid extraction protocol based on ternary component solvent systems . DLLME method has the advantages of simplicity of operation, rapidity, low cost, high recovery and enrichment factors, and has been proved to be a suitable preconcentration procedure for various metal ions [12,13]. In recent years, the application of Ionic Liquids (ILs) as solvents instead of organic solvents, in combination with various techniques, has attracted considerable attention in the field of analytical chemistry . Ionic liquids are liquid salts with melting points near or below room temperature. They are generally considered to be environmentally friendlier than common organic solvents and have unique chemical and physical properties such as negligible vapor pressure, non-flammability, good extractability for various organic compounds and metal ions as neutral or charged complexes, as well as tunable viscosity and miscibility with water and organic solvents .
A rapid and sensitive analytical method for the determination of oxolinic acid and flumequine in aqueous samples based on dispersiveliquid-liquidmicroextraction using ionic liquids (ILs) was developed. Based on the structural properties of the antibiotic agents studied, two ILs with different functionalities were required: ethyl-dimethyl-(2-methoxyethyl) ammonium tris(pentafluoroethyl)trifluorophosphate ([MOEDEA][FAP]) for extraction and 1-butyl-3- methylimidazolium tetrafluoroborate ([BMIM][BF 4 ]) to adjust the polarity of the medium. The significant experimental factors involved in DLLME were identified
This paper describes a dispersiveliquid–liquidmicroextraction (DLLME) procedure using room temperature ionic liquids (RTILs) coupled with flame atomic absorption spectrometry detection with microsample intro- duction system capable of quantifying trace amounts of lead. In the proposed approach, ammonium pyr- rolidine dithiocarbamate (APDC) was used as a chelating agent and 1-hexyl-3-methylimmidazolium bis (trifluormethylsulfonyl)imid as an extraction solvent was dissolved in acetone as the disperser solvent. The binary solution was then rapidly injected by a syringe into the water sample containing Pb 2+ complex. Some
Recently, ionic liquids (ILs)—semi-organic molten salts with an organic or inorganic anion and an organic cat- ion—have emerged as alternative extraction solvents for sample treatment because of their advantages of strong thermal stability, good miscibility with organic and aque- ous solvents, low vapor pressure, and good solubility for both organic and inorganic compounds. ILs have been utilized for the analysis of several kinds of organic com- pounds, such as benzoylurea insecticides, neonicotinoid insecticides, and endocrine-disrupting compounds [21– 23]. Compared with conventional extraction methods, less organic solvent was consumed during IL dispersiveliquid–liquidmicroextraction, and a higher extraction efficiency was achieved within a shorter extraction time.
microwave-assisted extraction (MAE) (Bartolom et al., 2005). However, modern trends in analytical chemistry are approached towards the simplification of sample preparation. Thus, the microextraction techniques are playing an important role in the determination of PAHs. Solid-phase microextraction (SPME) (Fernández- González et al., 2007), stir bar sportive extraction (SBSE) (Kolahgar et al., 2002) and liquid-phase microextraction (LPME) (Charalabaki et al., 2005) have been developed as alternative techniques to the classical LLE and SPE. Recently, a simple and rapid pre-concentration and micro extraction method named dispersiveliquid– liquidmicroextraction (DLLME) has been introduced and frequently used for determination of organic contaminants in liquid samples including of PAHs (Rezaee et al., 2006).
A very simple, rapid and sensitive dispersiveliquid-liquidmicroextraction (DLLME) followed by gas chromatography and flame ionization detection (GC-FID) was developed for the determination of phenol and carvacrol in honey samples. A mixture of 100 µl dichloromethane (extraction solvent) and 0.5 ml acetonitrile (disperser solvent) was rapidly injected into sample solution. Thereby a cloudy solution was formed. After centrifuging, the fine droplets of extraction solvent were sedimented in the bottom of the conical test tube. Sedimented phase (0.6 µl) was injected into the GC-FID system. Experimental parameters which control the performance of DLLME, such as type and volumes of extraction and disperser solvents, pH, salt effect and extraction time were investigated. Under optimum conditions obtained by the response surface methodology, the method was found to be linear in the range of 10-200 mg l -1 . The limits of detection for
Three methods named: single-drop micro- extraction (SDME), hollow fiber liquid-phase micro-extraction (HF–LPME), and dispersiveliquid-liquidmicroextraction (DLLME) are con- sidered as subset of the LPME method (29). The method of DLLME was introduced at first by Rezaee et al. (2). These researchers developed a rapid, economical, and environmentally friendly sample preparation technique. The DLLME can apply for many matrices, such as soil, urine, and foodstuffs. The extraction mechanism is based on the different inclinations of the analytes to the aqueous sample and the organic extractant. The major advantages of this method are simplicity, at least use of hazardous solvents, rapid extraction, and low cost.
A rapid, simple, and sensitive dispersiveliquid-liquidmicroextraction based on solidification of floating organic drop (DLLME-SFOD) method coupled with UV-Vis spectrophotometry has been applied for the extraction and determination of trace amounts of aluminium. The aluminium was extracted from the aqueous media containing aluminon and cetyltrimethylammonium bromide (CTAB). After rapid injection of the 1-undecanol mixture as the extraction solvent and ethanol as the disperser solvent into the sample, a cloudy mixture was formed and the complex was extracted into 1-undecanol. After centrifugation and cooling in an ice bath, the solidified organic drop on top of the solution was transferred into a vial which was melted at room temperature. Then, the organic phase containing the metal complex was diluted with ethanol and was transferred into a microcell for quantification. The pink chelate exhibits maximum absorbance at 535.0 nm, and with a preconcentration factor of 100.0 obeys Beer’s law over the concentration range of 1.0-15.0 µg l -1 of aluminium. The limit of detection of 0.14 μg l -1 and a relative standard deviation of 1.8% at 3.0 μg l -1 (n = 6) were obtained. The procedure was successfully applied for the determination of aluminium in tea and water samples.
A simple and efficient dispersiveliquid-liquidmicroextraction (DLLME) method coupled with microvolume UV-Vis spectrophotometry was developed for the determination of trace amounts of phosphate. This method is based on the formation of phosphomolybdate due to the reaction between molybdate and phosphate followed by its reduction with stannous chloride in aqueous sulfuric acid medium. The blue product was converted into its ion-pair with methyltrioctylammonium chloride (Aliquat-336) and then extracted into an organic solvent (carbon tetrachloride) dispersed in aqueous solution. The factors affecting on the process, such as concentration of sulfuric acid, ammonium molybdate and Tin(II) chloride in the sample solution, amount of methyltrioctylammonium chloride, volume of extraction solvent and reaction time were investigated and optimized. Under optimum conditions, the linear range was found to be 50-6500 ng ml -1 for phosphate, and the limit of detection was 12 ng ml -1 . The proposed method was applied for the determination of trace amounts of phosphate in different water and wastewater samples and satisfactory results were obtained.
A sensitive method has been studied for the determination of codeine phosphate in water samples using dispersiveliquid-liquidmicroextraction coupled with Uv-visible spectrophotometry. Parameters that affect on the extraction efficiency, such as kind and volume of the extraction and disperser solvent, extraction time, salt addition were investigated and optimized. Under the optimal conditions, the linearity of the method was obtained in the range 0.005-10 µg/mL with coefficient of (r 2 ) 0.9996. The limit of detection and relative standard deviation were 0.001 µg/mL (n=7) and 2.85 (c=2 µg/mL, n=5) respectively. Also, the proposed method was applied to the determination of codeine phosphate in water samples with satisfactory analytical results.
Dispersiveliquid-liquidmicroextraction (DLLME) followed by gas chromatography–flame ionization detec- tion (GC-FID), as a simple, rapid and efficient method, was developed for the determination of amitraz in honey samples. This method involves the use of an appropriate mixture of the extraction and disperser sol- vents for the formation of a cloudy solution in 5.0 mL aqueous sample containing amitraz. After extraction, phase separation was performed by centrifugation and the concentrated amitraz in the sedimented phase was determined by gas chromatography—flame ionization detection (GC-FID). Some important parameters such as the type and volume of extraction and disperser solvents, and the effect of pH and salt on the extraction recovery of amitraz were investigated. Under the optimum conditions (13 µL of carbon tetrachloride as an extraction solvent, 1 mL of acetonitrile as a disperser solvent, no salt addition and pH 6) preconcentration factor and the extraction recovery were 955 and 95.5%, respectively. The linear range was 0.01 - 1.0 mg · kg –1
ABSTRACT In this study, dispersiveliquid-liquidmicroextraction (DLLME) which is known for its simplicity, rapidity and high recovery was developed coupling with gas chromatography-flame ionization detector (GC-FID) for the determination of pesticides of different chemical groups in tomato and cucumber samples. Parameters affecting the extraction efficiency of DLLME such as types and volume of extraction solvent and dispersive solvent, extraction time and ionic strength of aqueous solution were studied and optimized. Under the optimized conditions (0.8 mL acetone, dispersive solvent; 14.2 µL tetrachloroethylene, extraction solvent; 20 s extraction time; no salt addition), the relative recoveries of pesticides from tomato and cucumber samples at a dilution factor of 1:25 were in the range of 94.58 – 103.34% and 96.46 – 109.45% respectively. The limits of detections (LODs) of all pesticides except diuron from tomato and cucumber extracts were ranged from 7.5 – 15 µg/L and 15 – 39 µg/L respectively. All the LODs of pesticides except diuron extracted from both tomato and cucumber extracts using the proposed DLLME method coupled with GC-FID were still found to be lower than the maximum residue levels (MRLs) established by European Union and / or Codex Alimentarius. ABSTRAK Dalam kajian ini, pengekstrakan mikro cecair-cecair serakan (DLLME) yang terkenal dengan keringkasan, kepantasan dan pemulihan yang tinggi telah dibangunkan gandingan dengan gas kromatografi- pengesan pengionan api (GC-FID) untuk penentuan racun perosak beraneka kumpulan kimia dalam sampel tomato dan timun. Parameter yang mempengaruhi kecekapan pengekstrakan DLLME seperti jenis dan isipadu pelarut pengekstrakan dan pelarut penyebar, masa pengekstrakan serta kekuatan ionic larutan akueus dikaji dan dioptimumkan. Di bawah syarat-syarat yang optimum (0.8 mL aseton, pelarut penyebar; 14.2 µL tetrakloroetilena, pelarut pengekstrakan; 20 s masa pengekstrakan; tiada tambahan garam), relative pemulihan racun perosak daripada sampel tomato dan timun dengan factor pencairan 1:25 adalah dalam lingkungan 94.58 – 103.34% dan 96.46 – 109.45% masing-masing. Had pengesanan (LODs) bagi semua racun perosak yang diekstrak daripada tomato dan timun kecuali diuron dengan menggunakan kaedah DLLME bergandingan dengan GC-FID yang dicadangkan masih didapati lebih rendah daripada tahap maksimum sisa baki racun perosak yang ditetapkan oleh European Union dan/ atau Codex Alimentarius.
liquid-phase extraction [11-15], cloud point extraction [16-18], and coprecipitation [19-21], has recently been documented in the literature. The ionic liquids (ILs) were used as environmentally friendly solvents because of their excellent physicochemical characteristics such as frivolous vapor pressure, economical, green, selective solubility, thermal stabilities, and good extracts for various organic compounds and metal ions [22-25]. Hence, the utilization of vortex-assisted IL-based dispersiveliquid–liquidmicroextraction technique (VA-IL-DLLME) method combined with FAAS has some advantages such as simplicity, economy, lower limit of detection (LOD), higher preconcentration factor (PF), and environmentally friendly.
phenylethanol from different samples, including supercritical fluid extraction (SFE) , solid phase extraction (SPE) , solid phase microextraction (SPME) [12-14], headspace-solid-phase microextraction (HS-SPME) [15, 16], liquid-liquidmicroextraction (LLME)  and stir bar sorptive extraction (SBSE) . Liquid-liquid extraction (LLE) is a classical method for clean-up and pre- concentration of analytes. Conventional extraction methods based on LLE are time-consuming and need a large amount of organic solvents, which are dangerous for human health and the environment. In the last decades, microextraction methods such as liquid phase microextraction (LPME), single drop microextraction (SDME), ultrasound-assisted emulsification microextraction (USAEME) and dispersiveliquid-liquidmicroextraction (DLLME) have attracted increasing attention as novel sample preparation techniques. These techniques are simple, low-cost, rapid, and require only very small sample and solvent consumption.
Dispersiveliquid-liquidmicroextraction (DLLME) is another type of microextraction method that consists of a trinary system of solvents including a high-density and water- immiscible extraction solvent (extractant), a disper- sive solvent highly miscible with the extraction solvent and aqueous sample, and an aqueous sample (Rezaee et al. 2006). The method based on the formation of very small droplets of extraction solvent in the sample solution after injection of extractant and dispersive solvent into aqueous sample (Shamsipur and Fattahi 2011). The large contact surface area between the extraction solvent and aqueous sample forms a cloudy mixture. This phenomenon facili- tates a rapid equilibration. When the cloudy solution is cen- trifuged, the extractant forms the sediment phase and removed with a microsyringe for later analysis (Yan and Wang 2013; Saraji and Boroujeni 2014).
ABSTRACT: In this research, a DispersiveLiquid-LiquidMicroExtraction (DLLME) method coupled to UV-vis spectrophotometry was developed for the indirect determination of silver ion. The method is based on the catalytic effect of the silver ion on the oxidation of congo red by potassium peroxodisulphate and extraction with DLLME procedure using chloroform (extraction solvent) containing cetyltrimethyl ammonium bromide which provides counter ion and also acts as a disperser. After extraction, the phase separation is performed with a centrifugation, and the silver ion is determined in the enriched phase by UV-Vis spectrophotometry. Several factors affecting the microextraction efficiency, such as pH of the solution, extraction time, type and volume of extraction solvent were investigated. Under optimum conditions, a linear calibration graph in the range of 0.5-105.0 ng/mL of silver ion in the initial solution with r 2 = 0.9987 (n=10) was obtained. Detection limit of method was 0.2 ng/mL
In the present study, a rapid and efficient analytical method based on vortex- assisted dispersiveliquid-liquidmicroextraction was studied and optimized for the determination of trace amounts of malondialdehyde in human serum plasma using one-variable-at-a-time and response surface methodology. For optimization of the malondialdehyde pre-concentration, seven factors in five- levels were employed for design of experiments. The results showed that the proposed method exhibits good linearity, precision, enrichment factor and detection limit for the extraction of this analyte. This method is fast, simple, sensitive, and inexpensive and allows sample extraction and pre-concentration to be done in a single step. This technique is environmentally friendly, since only less than a mililiter of organic solvent is required for extraction. More than 170 fold pre-concentration makes this method of choice for trace analysis of MDA and potentially other similar compounds without the need for a derivatization step. The total analysis time is 13 min.