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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]

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]