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In this work, a cheap and widely applicable dispersive liquid-liquid microextraction (DLLME) method was developed for the extraction of Ni(II) and Cu(II) from water and food samples and analysis using flame atomic absorption spectrometry. DLLME was assisted by orbital shaker, while ferrofluid as an extractant was based on deep eutectic solvent (DES). This ferrofluid was made of hydrophobic DES (hDES), composed of lauric acid and menthol (molar ratio 1:2), and toner powder@aliquat 336 magnetic particles. The extraction procedure does not require any heating or centrifugation. The method limits of detection value were 0.15 µg L−1 and 0.03 µg L−1 for Ni(II) and Cu(II) respectively along with wide linearity range (0.4–250 µg L−1). The validation of the method was performed using certified reference materials (CRMs). The studies revealed excellent accuracy between results obtained by the developed method and expected values for all CRMs. The relative recoveries of Ni(II) and Cu(II) ions ranged from 92.8% to 98.6%. The developed method was further used for the determination of Ni(II) and Cu(II) in real water and food samples and provided quantitative recoveries. [Display omitted] • Magnetic DES: Toner powder@aliquat 336 / lauric acid:menthol as extractant. • Robust and time saving miniaturized sample preparation method. • Validated method reliable for routine analysis of Ni and Cu in water and food. • Short extraction time (8 min) and high preconcentration factor (125) were obtained. • Sensitive (ppb level), selective and stable method towards complex sample matrix. [ABSTRACT FROM AUTHOR]

This manuscript presents a new method for selective extraction and determination of fosetyl-aluminum in fruits and vegetable samples based on ultrasonic-assisted dispersive liquid-liquid microextraction method using ionic liquids (IL-UA-DLLME). A UV-Visible spectrophotometer was used for detection and quantification. Plants used for sample collection were grown under controlled conditions in a greenhouse. Central composite design (CCD)-response surface methodology (RSM) analysis was used for the optimization of significant factors (volume of IL, pH, ultrasonication time, and THF volume). Under optimal conditions, the limit of detection and limit of quantification of the IL-UA-DLLME procedure were 1.5 ng mL−1 and 5.0 ng mL−1 respectively with relative standard deviation 1.9–3.3%. The developed IL-UA-DLLME procedure demonstrated linearity within the concentration range of 5–600 ng mL−1 with an R2 value of 0.9914. The enrichment factor was 114 with a recovery% of 94.2–98.6% (n = 3) at optimal conditions. The IL-UA-DLLME assay was used for the analysis of fosetyl-aluminum in a variety of food samples and was found highly selective and efficient. [Display omitted] • Ionic liquid-based pre-concentration method for fosetyl-aluminum analysis in foods. • Increased mass transfer via DLLME for fungicide isolation from plant material. • Fully validated method with proved applicability to real samples and routine analysis. • A highly sensitive, selective, and robust assay for environmental monitoring. • Fast analyte isolation followed by spectroscopic final determination stage [ABSTRACT FROM AUTHOR]

This paper presents a new analytical procedure based on combination of homogeneous liquid–liquid extraction (HLLE) and vortex-assisted dispersive liquid–liquid microextraction (VA-DLLME) for the accurate and reliable determination of ochratoxin A (OTA) in dried fruit samples. To enable selective extraction of the OTA, six hydrophobic deep eutectic solvents (hDESs) were prepared and tested as extraction solvents. Optimization of DES volume, pH, NaCl amount, and mixing time affecting the efficiency of VA-DES-DLLME step was achieved by central composite design (CCD). Using optimized conditions, the working range was obtained in the range 0.4–350 ng mL−1 with an enrichment factor of 138. The limit of detection was 0.12 ng mL−1. To evaluate the accuracy of the method, the samples were analyzed with both the HLLE-VA-DES-DLLME procedure and reference method. The precision of the method was investigated by intraday/interday studies. The robustness of the method was also evaluated by making minor changes to the optimized conditions. The HLLE-VA-DES-DLLME procedure was successfully applied to dried fruit samples and quantitative recoveries were obtained (92.1–99.2%) confirming its usefulness for implementation in routine analysis of food samples. [Display omitted] • Novel sample preparation microextraction based protocol for OTA determination. • hDES based on hexafluoroisopropanol and carnitine provide best performance. • Application of chemometric approach for method optimization. • Minimization of solvent consumption, high selectivity and method robustness. • LOD, LOQ, and EF were found as 0. 21 ng mL−1, 0.40 ng mL−1, 138 respectively. [ABSTRACT FROM AUTHOR]