Ionic-liquid-based, manual-shaking- and ultrasound-assisted, surfactant-enhanced emulsification microextraction for the determination of three fungicide residues in juice samples

Evaluation of green silicone surfactant-based vortex assisted dispersive liquid-liquid microextraction for sample preparation of organophosphorus pesticide residues in honey and fruit sample

A vortex assisted surfactant enhanced emulsification liquid-liquid microextraction based on non-ionic silicone surfactant was successfully developed for the determination of organophosphorus pesticides in food samples coupled to gas chromatography-mass spectrometry. A new type of non-ionic silicone surfactant composed of polysiloxane chains was employed as a green emulsifier to facilitate the emulsification of extraction solvent into the sample matrix, thereby intensifying the mass transfer of target analytes into the organic phase. The variables that affect the extraction were systematically optimized: 80 μL of hexane and 0.5% (v/v) of silicone surfactant were used as extraction solvent and surfactant respectively, the solution was mixed well under vortex agitation for 1 min with the addition of 4% (w/v) sodium sulfate. Under optimum conditions, the linearity of the method was obtained in the range of 0.1 - 200 μg/kg with good coefficient of determination varying from 0.9986 to 0.9996. The LOD and LOQ were in between 0.008 - 0.1 μg/kg and 0.02 - 0.3 μg/kg, respectively. Application of the proposed method to real samples gave satisfactory recovery values (80 - 118%) for the target analytes. The suggested approach has also proven to be convenient, expeditious and environmentally benign. This article is protected by copyright. All rights reserved.

Determination of imidacloprid and acetamiprid in bottled juice by a new DLLME-HPLC

A new kind of surfactant-emulsified vortex-assisted dispersive liquid-liquid microextraction method (SE-VA-DLLME) using benzyldimethyldodecylammonium chloride (BDDAC) as emulsifier and disperser has been developed for the determination of imidacloprid and acetamiprid in bottled grenadine and black currant juice samples prior to high-performance liquid chromatography-diode array detection. For grenadine juice and black currant juice, LODs were 0.78 and 0.45 μg/L and 0.81 and 0.83 μg/L and LOQs were 2.8 and 1.7 μg/L and 3.2 and 2.8 μg/L for imidacloprid and acetamiprid, respectively. The linear ranges were wider than 10-3000 μg/L with a correlation coefficient higher than 0.9913, the extraction recoveries were in the range of 61.6-84.2%, the enrichment factors were in the range of 27.0-43.3, and the recoveries and relative standard deviations of the studied neonicotinoids were in the range of 91.94-99.63% and 2.8-6.7%, respectively. The proposed method is presented as a simple, cheap, precise, accurate, and sensitive alternative for the determination of imidacloprid and acetamiprid in bottled grenadine juice and black currant juice samples.

Self-acidity induced effervescence and manual shaking-assisted microextraction of neonicotinoid insecticides in orange juice

A novel dispersive liquid-liquid microextraction that combines self-induced acid-base effervescent reaction and manual shaking, coupled with ultra high performance liquid chromatography with tandem mass spectrometry was developed for simultaneous determination of ten neonicotinoid insecticides and metabolites in orange juice. An innovative aspect of this method was the utilization of the acidity of the juice for a self-reaction between acidic components contained in the juice sample and added sodium carbonate which generated carbon dioxide bubbles in situ, accelerating the analytes transfer to the extractant of 1-undecanol. The total acid content of juice sample was measured to produce the maximum amount of bubbles with minimum usage of carbonate. Manual shaking was subsequently adopted and was proven to enhance the extraction efficiency. The factors affecting the performance, including the type and the amount of the carbon dioxide source and extractant, and ionic strength were optimized. Compared with conventional methods, this approach exhibited low limits of detection (0.001-0.1 µg/L), good recoveries (86.2-103.6%), high enrichment factors (25-50), and negligible matrix effects (-12.3-13.7%). The proposed method was demonstrated to provide a rapid, practical, and environmentally friendly procedure due to no acid reagent, toxic solvent, or external energy requirement, giving rise to potential application on other high acid-content matrices.

Magnetic dispersive solid-phase extraction based on graphene oxide/Fe3 O4 @polythionine nanocomposite followed by atomic absorption spectrometry for zinc monitoring in water, flour, celery and egg

BACKGROUND

Magnetic graphene oxide nanocomposite has been proposed as a promising and sustainable sorbent for the extraction and separation of target analytes from food matrices. Sample preparation based on nanocomposite presents several advantages, such as desired efficiency, reasonable selectivity and high surface-area-to-volume ratio.

RESULTS

A new graphene oxide/Fe₃ O₄ @polythionine (GO/Fe₃ O₄ @PTh) nanocomposite sorbent was introduced for magnetic dispersive solid-phase extraction and flame atomic absorption spectrometric detection of zinc(II) in water, flour, celery and egg. To fabricate the sorbent, an oxidative polymerization of thionine on the surface of magnetic GO was applied, while polythionine was simply employed as a surface modifier to improve extraction yield. The properties of the sorbent were characterized by transmission electron microscopy, scanning electron microscopy, X-ray diffraction, energy-dispersive X-ray analysis, vibrating sample magnetometry and Fourier transform-infrared spectroscopy. The calibration curve showed linearity in the range of 0.5-30 ng mL^-1 . Limits of detection (S/N = 3) and quantification (S/N = 10) were 0.08 and 0.5 ng mL^-1 , respectively.

CONCLUSION

The method was applied for trace-level determination of Zn(II) in water and food samples, and its validation was investigated by recovery experiments and analyzing certified reference material. © 2018 Society of Chemical Industry.

Quantification of Meloxicam in Human Plasma Using Ionic Liquid-Based Ultrasound-Assisted In Situ Solvent Formation Microextraction Followed by High-Performance Liquid Chromatography

A robust extraction method against the variations of sample ionic strength viz. ionic liquid-based ultrasound-assisted in situ solvent formation microextraction (IL-UA-ISFME) was coupled for the first time with high-performance liquid chromatography-ultraviolet detection (HPLC-UV), and successfully used as a more sustainable approach for the determination of meloxicam (MEL) in human plasma. Herein, a hydrophobic IL (1-butyl-3-methylimidazolium hexafluorophosphate) was formed by adding a hydrophilic IL (1-butyl-3-methylimidazolium tetrafluoroborate) to aqueous sample solution containing an ion-exchange reagent (sodium hexafluorophosphate). The target analyte was transferred into the IL medium while the extraction solvent was completely dispersed into the sample using ultrasonic irradiation and then, the settled enriched phase was injected to HPLC. Firstly, main factors affecting the microextraction performance were evaluated and optimized. The linearity was in the range of 5-1,500 ng mL-1 with regression coefficient corresponding to 0.997. Limits of detection (LOD; signal-to-noise ratio (S/N) = 3) and quantification (LOQ, S/N = 10) were 1 and 5 ng mL-1, respectively. An acceptable recovery range of 82.1-93.6% and satisfactory intra-assay (3.6-4.8%, n = 6) and inter-assay (3.3-5.1%, n = 9) precision as well as remarkable sample clean up exhibited good efficiency of the method. The freeze-thaw stability study was performed for samples and standard solutions. To study the applicability of the proposed method, it was employed for the determination of MEL in human plasma after oral administration of the drug and some pharmacokinetic data were achieved. The technique proved to be accurate and reliable for the screening intentions.

Trace determination of chlorpheniramine in human plasma using magnetic dispersive solid-phase extraction based on a graphene oxide/Fe3O4@polythionine nanocomposite combined with high-performance liquid chromatography

Graphene oxide/Fe₃O₄@polythionine (GO/Fe₃O₄@PTh) nanocomposite was fabricated for magnetic dispersive solid-phase extraction and high-performance liquid chromatography-ultraviolent detection (HPLC) of chlorpheniramine in human plasma.

Effervescence-assisted dispersive solid-phase extraction using ionic-liquid-modified magnetic β-cyclodextrin/attapulgite coupled with high-performance liquid chromatography for fungicide detection in honey and juice

In this study, a simple effervescence-assisted dispersive solid-phase extraction method was developed to detect fungicides in honey and juice. Most significantly, an innovative ionic-liquid-modified magnetic β-cyclodextrin/attapulgite sorbent was used because its large specific surface area enhanced the extraction capacity and also led to facile separation. A one-factor-at-a-time approach and orthogonal design were employed to optimize the experimental parameters. Under the optimized conditions, the entire extraction procedure was completed within 3 min. In addition, the calibration curves exhibited good linearity, and high enrichment factors were achieved for pure water and honey samples. For the honey samples, the extraction efficiencies for the target fungicides ranged from 77.0 to 94.3% with relative standard deviations of 2.3-5.44%. The detection and quantitation limits were in the ranges of 0.07-0.38 and 0.23-1.27 μg/L, respectively. Finally, the developed technique was successfully applied to real samples, and satisfactory results were achieved. This analytical technique is cost-effective, environmentally friendly, and time-saving.