Synthesis and characterization of phosphocholine chloride-based three-component deep eutectic solvent: application in dispersive liquid-liquid microextraction for determination of organothiophosphate pesticides.

A new type of deep eutectic solvent based on three components using phosphate salts has been synthesized, characterized, and applied in the extraction of eight organothiophosphate pesticides from honey samples. In this study, the deep eutectic solvent was prepared from phosphocholine choline chloride as a hydrogen bond acceptor and dichloroacetic acid and decanoic acid as hydrogen bond donors. The method consisted of two steps in which initially the analytes were extracted from the samples into a water-miscible organic solvent. In the second step, the extracted phase was mixed with the prepared deep eutectic solvent and the mixture was used in the following dispersive liquid-liquid microextraction method. The method was validated under optimal conditions, and it was found that it has low limits of detection (0.05-0.10 ng g-1 ) and quantification (0.19-0.36 ng g-1 ), good linearity (r2  ≥ 0.994), broad linearity (0.36-1000 ng g-1 ), and satisfactory repeatability (relative standard deviation ≤10% for intra- (n = 6) and inter-day (n = 4) precisions at a concentration of 2 ng g-1 of each analyte). The proposed method was applied in different honey samples, and malathion was found at a concentration of 29 ng g-1 in one sample. © 2019 Society of Chemical Industry.

Mokhtari N ，Torbati M ，Farajzadeh MA ，Afshar Mogaddam MR ... -  《-》

Synthesis of a green high density deep eutectic solvent and its application in microextraction of seven widely used pesticides from honey.

A green dispersive liquid-liquid microextraction using a new high density deep eutectic solvent (as an extraction solvent) has been developed and utilized in the simultaneous preconcentration and extraction of seven pesticides in honey followed by gas chromatography-flame ionization detection. The deep eutectic solvent is synthesized using menthol (as a hydrogen bond acceptor) and dichloroacetic acid (as a hydrogen bond donor) at a molar ratio of 1:2. Initially the analytes are extracted into acetone from the sample. After centrifuging, the synthesized deep eutectic solvent is added to the extract obtained from the previous step. Then this mixture is quickly injected into deionized water by a syringe for more concentration. A cloudy solution is formed by dispersion of fine droplets of the deep eutectic solvent by acetone into the aqueous solution and the pesticides are transferred into the extraction solvent. After extraction, phase separation is performed by centrifugation and the enriched analytes in the sedimented phase are determined. The influence of different parameters affecting the extraction efficiency was investigated and optimized. Under the optimized extraction conditions, enrichment factor for the analytes was obtained in the range of 279-428 with extraction recovery of 56-86%. Limits of detection and quantification were obtained in the ranges of 0.32-1.2 and 1.1-4.0 ng g-1, respectively. Relative standard deviations were ≤ 7% for intra- (n = 6) and inter-day (n = 5) precisions calculated at two concentrations of 10 and 50 ng g-1 of each analyte. Finally, some honey samples were effectively analyzed by the proposed method and diazinon was determined at ng g-1 concentration in one sample.

Farajzadeh MA ，Abbaspour M ，Kazemian R 《-》

In matrix formation of deep eutectic solvent used in liquid phase extraction coupled with solidification of organic droplets dispersive liquid-liquid microextraction; application in determination of some pesticides in milk samples.

In this work, a liquid-phase extraction procedure and dispersive liquid-liquid microextraction method based on deep eutectic solvents were combined and used for the simultaneous extraction of different classes of pesticides; including carbaryl, hexythiazox, pretilachlor, iprodione, famoxadone, sethoxydim and fenazaquin from milk samples. In the first step, a deep eutectic solvent was synthesized in milk sample and simultaneously, was used for extraction of the analytes along with precipitation of milk proteins. To assist the formation of the deep eutectic solvent and increasing the mass transfer rate of the analytes, ultrasonic irradiations was used. In the second step, the collected organic phase from pervious step was mixed (as dispersive solvent) with a water-immiscible deep eutectic solvent (ChCl: decanoic acid) and injected into deionized water. The cloudy solution was placed into an ice bath and the extraction solvent was solidified on the top of the solution. After removing the solid phase by a spatula, it was melted at room temperature and 1 μL of the extraction solvent was injected into the separation system. Under the optimum extraction conditions, low limits of detection and quantification within the ranges of 0.90-3.9 and 3.1-13 ng mL-1 were achieved, respectively. Precision of the method expressed as relative standard deviation was in the ranges of 3.8-5.3 and 4.8-6.9 for intra- and inter-day (n = 5) precision, respectively, at a concentration of 50 ng mL-1 of each analyte. Extraction recoveries and enrichment factors were between 64 and 89% and 320 and 445, respectively. Lastly, several milk samples were successfully analyzed using the proposed method.

Jouyban A ，Farajzadeh MA ，Afshar Mogaddam MR 《-》

Preparation of a new three-component deep eutectic solvent and its use as an extraction solvent in dispersive liquid-liquid microextraction of pesticides in green tea and herbal distillates.

A new solvent, deep eutectic solvent, in which there is growing interest, has been prepared and used as an extraction solvent in the dispersive liquid-liquid method of microextraction. To prepare the solvent, dichloroacetic acid, l-menthol, and n-butanol are mixed at a molar ratio of 4:1:1 and the deep eutectic solvent is formed after heating. Then a dispersive liquid-liquid microextraction method using the prepared solvent is used for the extraction and preconcentration of some pesticides from an aqueous sample. To carry out the procedure, the deep eutectic solvent is mixed with methanol and rapidly injected by a syringe into the aqueous sample containing the analytes. After centrifuging, an aliquot of the sedimented phase is injected into the gas chromatograph. The influence of several variables on the extraction efficiency was investigated and optimized. Extraction recoveries and enrichment factors were obtained in the ranges of 53-86% and 1760-2853, respectively. The intra- (n = 6) and inter-day (n = 5) precision of the method was satisfactory, with relative standard deviations ≤ 7% obtained at two concentrations of 10 and 50 μg L-1 of each analyte. Moreover, detection and quantification limits for the target analytes were obtained in the ranges of 0.11-0.23 and 0.38-0.74 μg L-1 , respectively. Different samples, including green tea, rose water, lemon balm, mint, and pussy willow distillates were analyzed successfully using the method that was developed, and chlorpyrifos was found in rose water at a concentration of 17 ± 1 μg L-1 (n = 3). © 2019 Society of Chemical Industry.

Farajzadeh MA ，Abbaspour M ，Kazemian R ，Afshar Mogaddam MR ... -  《-》

Preparation of multiwall carbon nanotube/urea-formaldehyde nanocomposite as a new sorbent in solid-phase extraction and its combination with deep eutectic solvent-based dispersive liquid-liquid microextraction for extraction of antibiotic residues in hone

A solid-phase extraction method combined with deep eutectic solvent-based dispersive liquid-liquid microextraction has been developed for the extraction of three antibiotics in honey samples prior to their determination by ion mobility spectrometry. In this method, first, a multiwall carbon nanotube/urea-formaldehyde nanocomposite was synthesized using co-precipitation polymerization method and then it was used as a sorbent for the analytes extraction from the samples. After that the adsorbed analytes were eluted from the sorbent using a water-miscible organic solvent. The collected elution solvent was mixed with tetrabutylammonium chloride:butanol deep eutectic solvent and the mixture was applied in the following microextraction method. The method provided low limits of detection and quantification in the ranges of 0.32-0.86 and 1.1-2.9 ng/g, respectively. The method had a proper repeatability expressed as relative standard deviation less than or equal to 9.1%. The validated method was successfully performed on different honey samples obtained from different producers.

Shahi M ，Javadi A ，Afshar Mogaddam MR ，Mirzaei H ，Nemati M ... -  《-》