Supercritical fluid extraction as an on-line clean-up technique for rapid amperometric screening and alternative liquid chromatography for confirmation of paraquat and diquat in olive oil samples

Miniaturized kapok fiber-supported liquid extraction for convenient extraction of pesticide residues in vegetable oils: Determination of organochlorine pesticides as a proof-of-concept study

In this paper, a miniaturized kapok fiber-supported liquid extraction (mini-KF-SLE) method was proposed for selective extraction of pesticide residues in vegetable oils. The natural kapok fiber was used as an inert oil support material based on its hydrophobic and lipophilic properties, and the extraction device was conveniently constructed by loading 15 mg of kapok fiber at the lower middle part of a 1-mL pipette tip. The vegetable oil sample (150 mg) without any pretreatment was directly loaded, followed by the addition of 150 μL of acetonitrile (ACN) as the extractant. After static extraction for 30 min, the extractant was pipetted out with a pipettor. As the proof of concept, it was applied for extracting eight organochlorine pesticides (OCPs) from vegetable oils and the eluate was analyzed by gas chromatography-electron capture detector (GC-ECD). Under optimized conditions, the extraction recoveries of OCPs were calculated to be in ranges of 35.8-79.5%. The satisfied quantitation ability was verified by the established method with coefficients of determination (R²) being greater than 0.99. The limits of detection (LODs) were in ranges of 2.0-50.0 ng/g. The relative recoveries were in ranges of 78.3-117.0% with the inter-/intra-day relative standard deviation (RSD) both being less than 13.3%. The potential of mini-KF-SLE to extract other kinds of pesticides was further verified by the successful extracting three triazole pesticides in vegetable oils with good extraction recoveries (>41.4%). The proposed mini-KF-SLE in combination with instrument detection techniques has the great potential in the low-cost and high-throughput determination of various pesticide residues in vegetable oils.

Solubility of vitamin A in supercritical CO2: experimental study and thermodynamic modeling

One of the best methods of extracting Vitamin A, as a helper of the immune body system and vision, was measured in supercritical carbon dioxide (SC-CO₂); Mole fractions were gained at practical conditions in which the temperature was in the range of 303–323 K and the pressure range was 90–235 bar, respectively. Moreover, four Equation of States [Soave–Redlich–Kwong, Peng–Robinson, Stryjek–Vera and Dashtizadeh–Pazuki–Taghikhani–Ghotbi (DPTG)] were compared with the experimental data. Also, the mixing rules of Van der Waals (vdW1 and vdW2) selected to correlate the solubility data of vitamin A. The outcomes indicate that each of EOSs coupled with vdW2, as a method of estimating the physicochemical and critical properties, were correlated with the solubility data of vitamin A in SC-CO₂ with more accuracy, in comparison with vdW1. Among the cubic EOSs, the DPTG model with vdW2 generated the most suitable correlation with the percentage average absolute relative deviation (Average Absolute Relative Deviation%) of 6.

Supercritical Fluid Extraction of Pesticides and Insecticides from Food Samples and Plant Materials

The principal intention of this study is presenting the attempts carried out for extracting, separating, and determining of the pesticide and insecticide residues existing in food and plant samples. In this regard, a set of content, including the explanations about the supercritical fluid extraction (SFE), supercritical fluid chromatography, and various types of pesticides are indicated. Besides, the parameters affecting the pesticides extraction composed of temperature, pressure, modifier, drying agent, and so on are discussed. Also, examples of insecticides extraction by SFE technique as an important subset of pesticides are indicated. Along with these items, some interesting works, concerning the innovations implemented in the field of SFE of pesticide and insecticide residues from foodstuff and plants are depicted.

Fast analysis of glufosinate, glyphosate and its main metabolite, aminomethylphosphonic acid, in edible oils, by liquid chromatographycoupled with electrospray tandem mass spectrometry

A method has been developed for the rapid, specific, accurate, precise and sensitive determination of glufosinate, glyphosate and its major metabolite, aminomethylphosphonic acid, in edible oils, by liquid chromatography coupled to tandem mass spectrometry. Oils were extracted with acidified water (1% formic acid), and the extracts were directly injected into an LC using a Hypercarb column as the stationary phase. The analytes were eluted by a mobile phase of methanol and water containing 1% acetic acid, and they were ionised by electrospray ionisation in negative ion mode. The method was validated and limits of quantification ranged from 5 μg kg-1 (aminomethylphosphonic acid) to 10 μg kg-1 (glyphosate and glufosinate). Three concentrations (10, 50 and 100 μg kg-1) were selected to perform recovery studies. Mean recoveries ranged from 81.4% to 119.4%. Intra and inter-day precision were lower than 19%. Different edible oils were analysed, and no residues of the studied herbicides were detected above limits of quantification.

Ionic liquid-modified silica-coated magnetic nanoparticles: promising adsorbents for ultra-fast extraction of paraquat from aqueous solution

In the present study, ionic liquid-modified silica-coated magnetic nanoparticles (Fe3O4@SiO2@IL) were synthesized and applied as adsorbents for extraction and determination of paraquat (PQ) followed by high-performance liquid chromatography. For assurance of the extraction efficiency, the obtained results were compared with those obtained by bared magnetic nanoparticles (MNPs). Experimental design and response surface methodology were used for optimization of different parameters which affect extraction efficiency of paraquat using both adsorbents. Under the optimized conditions, extraction recoveries in the range of 20-25 and 35-40 % with satisfactory repeatability values (RSDs%, n = 4) less than 5.0 % were obtained for bared MNPs and Fe3O4@SiO2@IL, respectively. The limits of detection were 0.1 and 0.25 μg/L using Fe3O4@SiO2@IL and bared MNPs, respectively. The linearity was obtained in the range of 0.25 to 25 μg/L and 0.5 to 25 μg/L for Fe3O4@SiO2@IL and bared MNPs, respectively, with the coefficients of determination better than 0.9950. Finally, Fe3O4@SiO2@IL was chosen as superior adsorbent due to more dispersion ability, higher extraction recovery, lower detection limit, as well as better linearity and repeatability. Calculated errors (%) were in the range of 3 to 10 % depicting acceptable accuracy for the analysis of PQ by the proposed method. Finally, the method was successfully applied for extraction and determination of PQ in some water and countryside soil samples.