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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]

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]

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]

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]