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In this work, walnut green husk has been used as a simple, cheap, biodegradable, and efficient adsorbent in dispersive solid phase extraction of Cd(II) and Pb(II) ions from some oil samples including edible, fish oil, and butter. In the next step, a dispersive liquid-liquid microextraction method was used to enrich the extracted analytes before their analysis with flame atomic absorption spectrometry. For this purpose, the adsorbent was obtained from agricultural wastes, dried in an isolated environment at ambient temperature, and mechanically ground to obtain a homogeneous powder. The parameters affecting the efficiency of the method were optimized. Low detection limits (0.12 and 0.32 µg l-1 for Cd(II) and Pb(II), respectively), low relative standard deviations (3.8% and 4.2% for Cd(II) and Pb(II), respectively), and determination coefficients close to 1 (0.991 and 0.995 for Cd(II) and Pb(II), respectively) were achieved. Also, the extraction recoveries for the target analytes were 89 and 96% for Cd(II) and Pb(II), respectively. [ABSTRACT FROM AUTHOR]

In present study, efficiency of three rapid, simple, and reliable sample preparation methods namely dispersive liquid–liquid microextraction (DLLME), air-assisted liquid–liquid microextraction (AALLME), and CO2-assisted liquid–liquid microextraction (CO2-ALLME) have been compared for the extraction and preconcentration of Pt(IV) and Pd(II) ions in environmental water samples prior to flame atomic absorption spectrometry. In this regard, the effect of various experimental parameters on efficiency of the methods like nature and amount of the disperser and extraction solvents, ionic strength, temperature, pH, etc., are investigated to reach high enrichment factors. Due to organic solvent consumption at µL level, all of the studied methods are inexpensive and convenient. The linear ranges of the calibration curves were 10.0–200, 6.0–175, and 6.0–175 μg L−1 for Pd(II), and 20–200, 4.0–200, and 7.0–200 μg L−1 for Pt (IV) ions in DLLME, AALLME, and CO2-ALLME methods, respectively. Extraction recoveries of 81.4, 92.1, and 88.9% for Pd (II) and 85.3, 98.4, and 93.4% for Pt(IV) ions were obtained in DLLME, AALLME, and CO2-ALLME, respectively. Finally, the developed methods were successfully used for the analysis of Pt(IV) and Pd(II) in various water samples. [ABSTRACT FROM AUTHOR]

A simple, efficient, green, and organic solventless dispersive liquid–liquid microextraction procedure was developed to determine Co(II) and Ni(II) ions in water and fruit juice samples by flame atomic absorption spectrometry. In this study, for the first time, both of dispersive and extraction solvents of the method are deep eutectic solvents. Therefore, it is performed without using any organic solvent. The dispersive solvent is composed of choline chloride and butyric acid at a molar ratio of 1:2. The solvent prepared from a mixture of choline chloride and phenylacetic acid at a molar ratio of 1:2 is acted as an extraction solvent. Effect of various analytical parameters such as constituents and molar ratios of dispersive and extraction solvents, volume of the synthesized solvents, temperature, ionic strength, and pH of sample solution on extraction efficiency of the method were investigated and optimized. After optimization of the method, good linearity in the ranges of 0.29–40 μg L−1 and 0.5–40 μg L−1 with coefficients of determination of 0.9919 and 0.9976 was obtained for Co(II) and Ni(II), respectively. Low limits of detection were obtained for Co(II) and Ni(II) (0.10 and 0.17 μg L−1, respectively). The extraction recoveries of the analytes were 95.4% and 92.8% for Co(II) and Ni(II), respectively. To investigate validity of the method, SPS-WW2 as a certificate reference material was analyzed with the proposed method. Finally, the method was successfully applied to determine Co(II) and Ni(II) ions in different water and fruit juice samples. [ABSTRACT FROM AUTHOR]

Vitamin based dispersive micro solid phase extraction procedure combined with dispersive liquid–liquid microextraction (DLLME) was introduced as an efficient and simple method for the extraction and preconcentration of some pesticides from vegetable samples. In this study, the analytes were extracted by vitamin B2 particles and the loaded analytes onto the sorbent were eluted by a water-miscible solvent and then concentrated into a ternary component deep eutectic solvent (tetrabutylammonium chloride: p-aminophenol: linalool DES) by performing DLLME approach. The extracted and concentrated analytes were determined by gas chromatography (GC) coupled to flame ionization detector (FID) and mass spectrometry (MS), independently. Finally, both GC–FID and GC–MS were used to measure the analytes. The effect of several parameters like: the amount of vitamin B2, eluent type, sample solution pH, and salt concentration on the introduced method efficiency was studied. Under the optimized conditions, wide linear ranges (2.6–1000 ng mL−1 by GC–FID and 0.29–100 ng mL−1 by GC–MS) were obtained. The limits of detection obtained by GC–FID and GC–MS were in the ranges of 0.35–0.78 and 0.01–0.09 ng mL−1, respectively. Restive standard deviations were ≤ 6.0% and ≤ 4.6% for GC–FID and GC–MS, respectively. Finally, the developed method was applied successfully for analysis of the selected pesticides in vegetable samples. [ABSTRACT FROM AUTHOR]

A vortex‐assisted dispersive micro‐solid‐phase extraction procedure using a new and green sorbent was developed as a simple, fast, and efficient sample preparation method for the extracting five pesticides in several fruit juice samples. In this study, for the first time, riboflavin was used as an efficient sorbent. A few milligrams of riboflavin was directly added into the aqueous solution containing the analytes to adsorb them. After adsorption the analytes, they were desorbed and more concentrated by a dispersive liquid–liquid microextraction procedure. The influence of several effective parameters such as amount of riboflavin, pH, vortex time, eluent nature and volume, and extraction solvent type and volume on the extraction efficiency was investigated. In optimal conditions, linear ranges of the calibration curves were broad. The limits of detection and quantification were attained in the ranges of 0.56–1.5 and 1.9–0.52 ng mL−1, respectively. The proposed method demonstrated to be suitable for concurrent extraction of the studied pesticides in various fruit juice samples with high enrichment factors (320–360) and precision (relative standard deviation ≤7.8% for intra‐ [n = 6] and interday [n = 4] precisions at a concentration of 25 ng mL−1 of each pesticide). [ABSTRACT FROM AUTHOR]

A green and efficient dispersive liquid-liquid microextraction method based on a new deep eutectic solvent has been developed for the preconcentration and extraction of cobalt and nickel ions. The deep eutectic solvent is formed by mixing choline chloride (hydrogen bond acceptor) and 4-aminophenol (hydrogen bond donor). Then, it is used as a chelating agent as well as extraction solvent. Under the optimum experimental conditions, the linear ranges for Ni(II) and Co(II) were 0.80–50 and 0.50–50 µgL−1, respectively, by flame atomic absorption spectrometry. The obtained detection limits were 0.30 and 0.22 µg L−1 for Ni(II) and Co(II), respectively. ChCl: choline chloride; DES: deep eutectic solvent; DLLME: dispersive liquid-liquid microextraction; EF: enrichment factor; ER: extraction recovery; FAAS: flame atomic absorption spectrometry; LOD: limit of detection; LOQ: limit of quantification. [ABSTRACT FROM AUTHOR]

BACKGROUND: A method has been developed based on a three–phase system, followed by dispersive liquid–liquid microextraction for the extraction of seven pesticides from soya milk prior to analysis by gas chromatography‐flame ionization detection. The base of this method is the different extraction capability of the components of soya milk according to each of the phases involved. In this procedure, a homogeneous solution consisting of soya milk and a water–miscible solvent (acetonitrile) is separated into two phases in the presence of Na2SO4 and the analytes are extracted into the produced acetonitrile droplets. The acetonitrile phase is mixed with a pre‐concentration solvent to perform the next microextraction procedure for further enrichment of the analytes. RESULTS: Limits of detection and quantification were reached in the ranges of 0.11–0.35 and 0.35–1.20 µg L−1, respectively. Enrichment factors and extraction recoveries were in the ranges of 562–933 and 56–93%, respectively. Relative standard deviations were ≤7% for intra– (n = 6) and inter–day (n = 5) precisions at two concentrations of 10 and 50 µg L−1 of each analyte. CONCLUSION: The proposed method was applied to the analysis of pesticides in soya milk samples at µg L−1 concentrations. © 2019 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

In this work, an efficient magnetic sorbent has been prepared using the extract of Tanacetum leaves and used in magnetic dispersive solid phase extraction of Cu(II) and Pb(II) ions from high volume of milk samples performed in a narrow-bore tube. For this purpose, first, the sorbent was prepared by mixing Fe 3 O 4 magnetic nanoparticles and Tanacetum leaves extract. After precipitation of the milk proteins with trichloroacetic acid, the sedimented compounds were removed and the upper solution was filled into the narrow-bore tube. Then after that, the mg-level of the prepared sorbent was added. After doing the extraction procedure, the sorbent particles were removed from the tube in the presence of a magnetic field. The adsorbed analytes were desorbed by methanol and to achieve low detection limits, the eluent obtained from the first step was subjected to dispersive liquid-liquid microextraction. Finally, the enriched analytes were monitored by flame atomic absorption spectrometry. The important parameters affecting the method efficiency such as the sorbent amount, type and volume of elution and extraction solvents, vortex time, pH, and ionic strength were studied. Under optimized conditions, the proposed method showed linear ranges of 0.50–40 and 0.75–40 µg L−1 for Cu(II) and Pb(II) ions, respectively. Limits of detection were obtained 0.16 and 0.22 µg L−1 for Cu(II) and Pb(II), respectively. Enrichment factors of 182.5 and 173.7 and extraction recoveries of 95.8 % and 91.2 % were obtained for Cu(II) and Pb(II), respectively. The relative standard deviations (intra- and inter-day precisions) for 5 and 25 µg L−1 of each cation were between 2.4 % and 4.3 %. • Tanacetum extract was used for functionalisation of Fe 3 O 4. • The prepared MNPs was used for the extraction of heavy metals from milk. • The MDSPE was combined with a dispersive liquid-liquid microextraction procedure. • The method has low LODs and LOQs, high EFs and ERs. [ABSTRACT FROM AUTHOR]

BACKGROUND A combination of magnetic solid‐phase extraction using an efficient and cheap magnetic sorbent obtained from sand and dispersive liquid–liquid microextraction has been developed for the extraction of nine multiclass pesticides (clodinafop‐propargyl, haloxyfop‐R‐methyl, fenoxaprop‐P‐ethyl, oxadiazon, penconazole, diniconazole, chlorpyrifos, fenazaquin, and fenpropathrin) from commercial fruit juices (sour cherry, pomegranate, grape, watermelon, orange, apricot, and peach juices). The enriched pesticides were determined by gas chromatography–flame ionization detector and gas chromatography–mass spectrometry. The sorbent was natural iron oxide entrapped in silica along with some impurities. In this method, to extract the analytes from the samples, an appropriate amount of the magnetic sorbent (at mg level) is added. Then the sorbent particles are isolated from the solution using an external magnetic field and the adsorbed analytes are desorbed from the sorbent by acetone. In the following, a dispersive liquid–liquid microextraction procedure is carried out to concentrate the analytes more and to reach low limits of detection. RESULTS: Under optimized extraction conditions, the method revealed satisfactory repeatability (relative standard deviation ≤8% for intra‐day and inter‐day precision), reasonable extraction recovery (43.3–55.9%), high enrichment factors (433–559), and low limits of detection (0.45–0.89 μg L−1). CONCLUSION: The method was applied in the analysis of pesticides in various fruit juices. Chlorpyrifos was found in peach juice at a concentration of 27 ± 2 μg L−1 (n = 3) using a gas chromatography–flame ionization detector. To verify the results, the peach juice was also injected into gas chromatography–mass spectrometry after applying the proposed extraction method. © 2022 Society of Chemical Industry. [ABSTRACT FROM AUTHOR]

A simple, green, rapid, and efficient ligandless dispersive liquid-liquid microextraction procedure based on solidification of a ternary deep eutectic solvent has been proposed for the extraction of trace amounts of Cd(II), Cu(II), and Pb(II) ions in milk samples prior to their determination by flame atomic absorption spectrometry. Initially, a suitable mole ratio of sorbitol, menthol, and mandelic acid are mixed in a test tube, and after heating, a deep eutectic solvent with low density compared to water is formed. The synthesized solvent is used as a chelating agent and an extraction solvent in the extraction of some heavy metal ions from milk samples. The influence of several effective parameters on the responses and extraction recoveries of the analytes was investigated. Under the optimum experimental conditions, the linear ranges were in the ranges of 1.0–40 μg L−1 for Cd(II) and Pb(II), and 1.0–25 μg L−1 for Cu(II). The obtained relative standard deviations (n = 6, C = 2.5 μg L−1 of each cation) and detection limits were in the ranges of 3.4–4.1% and 0.38–0.42 μg L−1, respectively. Finally, the developed method was successfully applied for the determination of Cd(II), Cu(II), and Pb(II) ions in different milk samples. Image 1 • An efficient ligandless DLLME method using a synthesized ternary DES is proposed for the extraction and preconcentration of Cd(II), Cu(II), and Pb(II) ions at trace levels from milk samples. • A few microliters of the synthesized DES was used simultaneously as a complexing agent and an extraction solvent, therefore, the extraction was performed without using any organic solvent. • This study is the first report on the application of the present method for the extraction of heavy metals in milk samples. • The proposed method offers numerous advantages, such as simplicity, ease of operation, and low cost. • The developed method was used for the determination of the analytes in different milk samples. [ABSTRACT FROM AUTHOR]

Abstract: In this study, a developed technique was reported for extraction and pre-concentration of methamphetamine (MAMP) and 3,4-methylenedioxymethamphetamine (MDMA, ecstasy) from urine samples using molecularly imprinted-solid phase extraction (MISPE) along with simultaneous derivatization and dispersive liquid–liquid microextraction (DLLME). Molecularly imprinted microspheres as sorbent in solid phase extraction (SPE) procedure were synthesized using precipitation polymerization with MAMP as the template. Aqueous solution of the target analytes was passed through MAMP-MIP cartridge and the adsorbed analytes were then eluted with methanol. The collected eluate was mixed with butylchloroformate which served as the derivatization reagent as well as the extraction solvent. The mixture was immediately injected into deionized water. After centrifugation, 1μL of the settled organic phase was injected into gas chromatography–flame ionization detection (GC–FID) or gas chromatography–mass spectrometry (GC–MS). Various experimental parameters affecting the performance of both of the steps (MISPE and DLLME) were thoroughly investigated. The calibration graphs were linear in the ranges of 10–1500ngmL−1 (MAMP) and 50–1500ngmL−1 (MDMA), and the detection limits (LODs) were 2 and 18ngmL−1, respectively. The relative standard deviations (%RSDs) obtained for six repeated experiments (100ngmL−1 of each drug) were 5.1% and 6.8% for MAMP and MDMA, respectively. The relative recoveries obtained for the analytes in human urine samples, spiked with different levels of each drug, were within the range of 80–88%. [Copyright &y& Elsevier]