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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 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, simple, rapid, and efficient ligandless air-assisted liquid-liquid microextraction procedure based on solidification of a ternary deep eutectic solvent was developed for the extraction of trace amounts of cadmium(II) and zinc(II) ions in aqueous samples prior to their determination by flame atomic absorption spectrometry. For this purpose, the deep eutectic solvent is formed by mixing sorbitol, menthol, and mandelic acid at a suitable mole ratio and after heating for a short time, a deep eutectic solvent with low density compared to water is synthesised. The synthesised solvent is used as a chelating agent and also as an extraction solvent. Under the optimum experimental conditions, the linear ranges were obtained in the ranges of 0.5–12.5 and 0.5–10.0 µg L−1 for Zn(II) and Cd(II), respectively. The relative standard deviations (n = 6, C = 2.5 µg L−1 of each cation) were 4.2% and 3.4%, for Cd(II) and Zn(II), respectively. Moreover, the obtained detection limits were 0.15 and 0.12 µg L−1 for Cd(II) and Zn(II), respectively. The accuracy of the developed method was studied by analysing SPS-WW2 Batch 108 water as a certified reference material. Finally, the proposed method was successfully applied in the determination of Cd(II) and Zn(II) ions in water and fruit juice samples. Abbreviations: AALLME: Air-assisted liquid-liquid microextraction; ER: Extraction recovery; FAAS: Flame atomic absorption spectrometry; LOD: Limit of detection; LOQ: Limit of quantification; RSD: Relative standard deviation [ABSTRACT FROM AUTHOR]

In this study, a simple and rapid sample preparation method named liquid-nitrogen-induced homogeneous liquid–liquid microextraction has been developed for the extraction and pre-concentration of Co(II) and Ni(II) ions before their analysis by flame atomic absorption spectrometry. For this purpose, first, acetonitrile containing 8-hydroxyquinoline is added into a sample solution and the mixture is vortexed. As a result, a homogeneous solution is formed. Subsequently, the solution is cooled using liquid nitrogen for a few seconds. By this process, due to difference in the freezing point of acetonitrile and water, the homogeneous state is broken and the analytes (as oxinate complexes) are extracted into liquid acetonitrile phase collected on top of the frozen aqueous phase. The linear dynamic ranges obtained for Ni(II) and Co(II) were 1.0–30 and 0.50–20 μg L−1, respectively. The obtained limits of detection were 0.36 and 0.20 μg L−1 for Ni(II) and Co(II), respectively. [ABSTRACT FROM AUTHOR]

A green, simple, rapid and efficient solventless temperature-assisted homogeneous liquid-liquid microextraction based on 8-hydroxyquinoline as complexing agent and extractant, followed by flame atomic absorption spectrometry was developed for the extraction, enrichment, and determination of trace amounts of nickel and cobalt in aqueous samples. For this purpose, first, a specified amount of 8-hydroxyquinoline is added to the analytes solution. Then the temperature of the solution is increased to melt 8-hydroxyquinoline and form a homogeneous solution. Then, it is cooled to room temperature and a cloudy solution is formed due to decreasing 8-hydroxyquinoline solubility. The solution is then centrifuged, and 8-hydroxyquinoline particles containing the produced complexes (8-hydroxyquinoline-cation) are collected at the bottom of the tube. They are removed and dissolved in a suitable solvent and injected to the detection system. The main parameters affecting the extraction efficiency, such as the amount of 8-hydroxyquinoline, solvent nature, pH, extraction temperature and heating time were investigated. Under optimum conditions, linear ranges for Co(II) and Ni(II) were 1-100 and 0.5-75 µg L−1, respectively. Relative standard deviations for intra- and inter-day precisions calculated from six repeated determinations at three different concentrations of Co(II) and Ni(II) were ≤5.2 %. Moreover, the obtained detection limits of the analytes were 0.35 and 0.20 µg L−1 for Co(II) and Ni(II), respectively. The accuracy of the developed procedure was checked by analysing SPS-WW2 Batch 108 water as a certified reference material. Finally, the developed method was successfully applied for the determination of the selected cations in water and fruit juice samples. [ABSTRACT FROM AUTHOR]

[Display omitted] • A sorbent was prepared using a magnetized metal–organic framework covered with the layer of a selective polymer. • A magnetic molecularly imprinted polymer (Fe 3 O 4 @UiO-66-NH 2 @MIP) nanocomposite was synthesized for extraction of imidacloprid. • The sorbent has excellent selectivity , good adsorption capacity, high extraction recovery, and acceptable reusability. • The linear range of 0.625–80 ng/L with a coefficient of determination of 0.9984 was obtained. • The detection and quantification limits were 0.187 and 0.625 ng/L, respectively. In this study, a magnetic molecularly imprinted polymer (Fe 3 O 4 @UiO-66-NH 2 @MIP) nanocomposite was synthesized for preconcentration, extraction, and selective analysis of imidacloprid using unique characteristics of magnetic iron oxide nanoparticles, metal–organic framework, and molecular imprinted polymer. The synthesized sorbent was investigated using Scanning electron microscopy and Fourier-transform infrared spectroscopy. The results of the characterization analyses ensured the successful synthesis. The relevant optimization parameters such as amount of the sorbent, type and time of agitation, pH, ionic strength, and type and volume of desorption solvent were investigated and optimized. High performance liquid chromatography-tandem mass spectrometry was used in the analysis of the enriched analytes. Under the optimum conditions detection and quantification limits were 0.187 and 0.625 ng/L, respectively. The linear range of 0.625–80 ng/L with a coefficient of determination of 0.9984 was obtained. The obtained results showed that the synthesized sorbent had excellent selectivity for the analyte, good adsorption capacity, high extraction recovery (92.4 %), acceptable stability, and good reusability. Finally, the developed method was successfully applied for the analysis of imidacloprid in different fruit juice samples. [ABSTRACT FROM AUTHOR]

A metal organic framework (MOF)-based dispersive solid phase extraction procedure was introduced using a hydrophobic sorbent for the extraction of multi class pesticides from fruit juice samples prior to their determination by high performance liquid chromatography-tandem mass spectrometry. For this purpose, NH 2 -UiO-66(Zr) MOF was synthesized by a hydrothermal approach. Then the sorbent was silylated and used in the extraction procedure. The extraction procedure was done by using 7 mg of the sorbent from 5 mL of a sample solution containing the analytes. After that, the extracted analytes were eluted and preconcentrated by vaporizing the elution solvent. The method was linear within the range of 0.29–500 ng mL−1. The limits of detection, intra- and inter-day relative standard deviations, and extraction recoveries were in the ranges of 0.02–0.1 ng mL−1, 2.9–8.8%, 6.8–14.4%, and 74–89%, respectively. Performing the method on the selected samples showed that they were free of the analytes. This method can help to monitor the studied pesticides in juice samples as well as improving the safety of foods. • A hydrophobic MOF was synthesized and used in extraction procedure. • DSPE method was developed for extraction of pesticides from fruit juices. • HPLC-MS/MS method was used for determination of pesticides. • Low cost, easiness, and effective sample preparation were advantages of the method. [ABSTRACT FROM AUTHOR]