Polycarbonate-coated magnetic nanoparticles for the extraction of imipramine and its primary metabolite from urine.

This study introduces a reliable and inexpensive magnetic dispersive solid phase extraction to extract imipramine and its primary metabolite (desipramine) from urine samples. To accomplish this aim, Fe3 O4 magnetic nanoparticles were synthesized by sonication, subsequently, polycarbonate was precipitated gradually onto the surface of them to form the adsorbent. Extraction recoveries of 85% and 76%, enrichment factors of 57 and 51, limits of detection of 2.5 and 2.8 µg/L, and limits of quantification of 8.3 and 9.3 µg/L were obtained for imipramine and desipramine under the optimal conditions, respectively. In addition, relative standard deviations for intra- (n = 6) and inter-day (n = 5) precisions at two concentrations (50 and 100 µg/L of each analyte) were less than or equal to 4%. Short extraction time, good repeatability, high enrichment factors, and simplicity are the main advantages of the proposed method.

Development of a magnetic dispersive solid phase extraction method by employing folic acid magnetic nanoparticles as an effective, green, and reliable sorbent followed by dispersive liquid-liquid microextraction for the extraction and preconcentration of seven pesticides from fruit juices.

Folic acid magnetic nanoparticles have been prepared and utilized as an effective and reliable sorbent in magnetic dispersive solid phase extraction combined with dispersive liquid-liquid microextraction for the extraction of seven pesticides from different juices before their determination by gas chromatography-flame ionization detector. The sorbent is prepared through ball milling process using a proper mixture of folic acid and magnetic iron oxide. Characterization of the sorbent was done with X-ray diffraction pattern, scanning electron microscopy, and vibrating sample magnetometry. In the current study, limits of detection were in the range 0.12-0.33 µg L-1. Relative standard deviations at a concentration of 40 µg L-1 of each analyte were in the ranges of 2.15-5.14% for intra-day (n = 6) and 3.78-6.91% for inter-day (n = 4) precisions. Extraction recoveries and enrichment factors were obtained in the ranges of 70-88 % and 566-708, respectively. The performance of the method was evaluated by determination the selected pesticides in different samples. Graphical Abstract.

Development of dispersive solid phase extraction utilizing folic acid as an efficient and green sorbent followed by dispersive liquid-liquid microextraction for the extraction of some plasticizers from aqueous samples.

In this investigation, folic acid has been used as an efficient and green sorbent in dispersive solid phase extraction for the extraction of di(2-ethylhexyl) adipate and three phthalate esters from the plastic-packed liquids before their determination with gas chromatography-flame ionization detection. This is the first report on the application of pure folic acid as a sorbent. In this work, limits of detection and quantification were in the ranges of 0.13-0.46 and 0.43-1.50 µg/L, respectively. Relative standard deviations were in the ranges of 2-5% for intra- (n = 6) and 4-7% for interday (n = 4) precisions at a concentration of 20 µg/L for each analyte. Enrichment factors and extraction recoveries were obtained in the ranges of 365-670 and 45-84%, respectively. Efficiency of the method was evaluated by analyzing the analytes in various plastic-packed liquids.

Development of a dispersive solid phase extraction method based on in situ formation of adsorbent followed by dispersive liquid-liquid microextraction for extraction of some pesticide residues in fruit juice samples.

A new mode of dispersive solid phase extraction based on in situ formation of adsorbent in aqueous phase has been introduced as an efficient method for the extraction of some pesticide residues in fruit juice samples. In this method, polycarbonate which is an inexpensive polymer is used as an adsorbent for the first time. The method is followed by dispersive liquid-liquid microextraction for more enrichment of the analytes. In the present study, a proper amount of the polymer is dissolved in N,N-dimethyl formamide and the obtained solution is injected into an aqueous phase containing the analytes. After injection, polycarbonate particles are formed and adsorbed the analytes. Then, the adsorbent is separated from the aqueous solution and eluted by acetone. The obtained acetone phase is mixed with 1,1,1-trichloroethane and the mixture is dispersed into deionized water and a cloudy solution is formed. Ultimately, after centrifugation, the obtained sedimented phase containing the extracted analytes is injected into gas chromatography-flame ionization detection. In the proposed method, the adsorbent synthesis step, which often is a time-consuming, expensive, and laborious step in most adsorbent-based sample preparation methods, has been removed. Moreover, there is no need for sonication or vortex agitation. Under the optimized experimental conditions, the relative standard deviation was equal or less than 7% for intra- (n = 6) and inter-day (n = 5) precisions at a concentration of 50 µg L-1 of each pesticide. The limits of detection and quantification were in the ranges of 0.34-1.2 and 1.1-4.0 µg L-1, respectively. In addition, extraction recoveries and enrichment factors varied in the ranges of 44-89% and 220-443, respectively.

Deep eutectic solvent based gas-assisted dispersive liquid-phase microextraction combined with gas chromatography and flame ionization detection for the determination of some pesticide residues in fruit and vegetable samples.

In this study, a gas-assisted dispersive liquid-phase microextraction method using a deep eutectic solvent as the extraction solvent combined with gas chromatography and flame ionization detection was developed for the extraction and determination of some pesticide residues in vegetable and fruit juice samples. In this method, choline chloride and 4-chlorophenol at a molar ratio of 1:2 were mixed. By heating and vortexing, a clear, water-immiscible, and homogeneous liquid was formed. The obtained deep eutectic solvent was added to an aqueous solution of the analytes in a conical test tube. Air was bubbled into the aqueous solution and a cloudy solution was obtained. During this step, the analytes were extracted into the fine droplets of the extraction solvent. After centrifugation, an aliquot of the settled phase was injected into the separation system. Under the optimum extraction conditions, enrichment factors, and extraction recoveries were obtained in the ranges of 247-355 and 49-71%, respectively. The obtained values for the limits of detection and quantification were in the ranges of 0.24-1.4 and 0.71-4.2 µg/L, respectively. The proposed method is simple, fast, efficient, and inexpensive.