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For the hyphenating of dispersive liquid–liquid microextraction (DLLME) with nano mesoporous solid-phase evaporation (SPEV) as a novel method, MCM-41@SiO2 was synthesized and used as a nano mesoporous adsorbent for coating on the solid-phase fiber, preconcentration of fluoxetine antidepressant drug (as a model compound), and total evaporation of the extraction solvents obtained by the DLLME method. To detect the analyte molecules, a corona discharge ionization–ion mobility spectrometer (CD–IMS) was applied. In order to increase the extraction efficiency and the IMS signal of the fluoxetine drug, some variables including extraction solvent and its volume, disperser solvents and its volume, sample solution pH, desorption temperature, and evaporation time of the solvent from the solid-phase fiber were chosen and optimized. Some analytical parameters including limit of detection (LOD), limit of quantification (LOQ), linear dynamic range (LDR) with determination coefficient, and relative standard deviations (RSDs) were calculated under the optimized conditions. LOD (S/N = 3), 3 ng mL−1; LOQ (S/N = 10), 10 ng mL−1; LDR, 10–200 ng mL−1; and intra- and inter-day RSDs (n = 3), 2.5% and 9.6% for 10 ng mL−1, and 1.8% and 7.7% for 150 ng mL−1, respectively. To investigate the ability of the hyphenated method to determine fluoxetine in real samples, fluoxetine tablets, and some biological samples such as human urine and blood plasma were selected and the relative recovery values were calculated to be 85–110%. The accuracy of the proposed method was compared with that of the HPLC standard method. [ABSTRACT FROM AUTHOR]

This paper seeks to produce UiO-66-NH2/Gly/GO nanocomposite, which is solvothermally synthesised by the “prefunctionalisation” approach using 2-aminoterephthalic acid as an organic linker in a Teflon lined autoclave and its linking to a graphene surface by glycine and finally characterized by methods such as FTIR spectrometer, Powder X-ray diffraction (XRD), energy dispersive X-ray analysis (EDAX), thermal stability measurement (TGA), transmission electron microscope (TEM), scanning electron microscope (SEM) and the Brunauer-Emmet-Teller (BET). UiO-66-NH2/Gly/GO nanocomposite has been exploited as an adsorbent in solid phase microextraction (SPME) method and also the pesticide chlorpyrifos as an organophosphorous pesticide is selected for the model compound. As for a determination system, Corona discharge ionization-ion mobility spectrometry (CD-IMS) has been employed. The nanocomposite capability in extracting the target analyte before and after the coating of the GO has been experimentally investigated. The IMS sensitivity has been strikingly increased in the course of using the GO as the nanocomposite coating. In order to increase the extraction efficiency and preconcentration of the analyte, both extraction temperature and time are scrutinized. All through this method, analysis factors are achieved as follows: linear dynamic range (LDR); 0.5-20.0 μgL-1, correlation coefficient (R²); 0.9992, the limit of quantification (LOQ); 0.5 μgL-1, and limit of detection (LOD); 0.15 μgL-1 . On the whole, the proposed approach seems to be regarded as a successful method for analyzing the organophosphouros pesticide. [ABSTRACT FROM AUTHOR]

An appropriate injection port was designed and constructed for direct analysis of stir-bar sorptive extractions using an ion mobility spectrometry (IMS). The novel design of the port offers great simplicity in use, high sensitivity, and high thermal and mechanical stability. The sol-gel technique was applied to prepare polydimethylsiloxane absorbent on a stir-bar. The parameters affecting extraction efficiency including stirring rate, extraction temperature, extraction time, salt addition and desorption temperature were optimized. The detection limit of the method was calculated to be 1.5 μg L −1 , for diazinon, an organophosphorus pesticide selected as a test compound. The linear dynamic range was obtained to be 5.0–200.0 μg L −1 with a determination coefficient of 0.9991 for the test compound. The intra- and inter-day relative standard deviations were calculated to be 4% and 5%, respectively. Agricultural wastewater, well water, and apple were selected as real samples. The detection limit was calculated to be 1.5 μg L −1 and 7.5 μg kg −1 for the real water samples and the apple sample, respectively. The recovery values (%) were 105 ± 6, 107 ± 3 and 96 ± 6 for the spiked agricultural wastewater, well water and apple samples, respectively. The results revealed that the injection port can be used for direct analysis of samples extracted by any sorbent support, without any further sample preparation. [ABSTRACT FROM AUTHOR]

• Silica aerogel thin film microextraction was coated by organic solvent and presented as a sample preparation method. • The proposed method was applied for the extraction of molinate before analyzing by CD-IMS. • The method showed an amazing increase in the extraction efficiency relative to TFME alone. A hyphenated method consisting of liquid-phase microextraction and solid-phase microextraction was presented as a sample preparation method. To that end, silica aerogel thin film microextraction prepared by electrospinning procedure was coated by organic solvent (tetrachloromethane) and used for extraction of molinate herbicide as a test compound. Corona discharge ionization-ion mobility spectrometry was applied as the detection system. Some parameters affected the extraction efficiency were evaluated and optimized with the response surface method. Under optimum conditions, the linear dynamic range was obtained 0.20–7.0 µg L−1, and the method detection limit and limit of quantification were obtained 0.075 and 0.20 µg L−1, respectively. The relative standard deviations of intra- and inter-day were calculated 4% and 7%, respectively, and the enrichment factor for the spiked sample (2 µg L−1) was obtained 600. Different real samples, including tomato, apple, carrot, agricultural wastewater, well water, river water, and drinking water samples were used for investigating the capability of the proposed method. The relative recovery values for these samples were obtained in the range of 90–108%. The satisfactory results disclosed that the organic solvent- thin-film microextraction could be utilized as an efficient sample preparation method for analyzing molinate in complex matrices. [ABSTRACT FROM AUTHOR]

Thin film nanofibers containing ZnTiO3 nanoparticles were used for rapid and efficient evaporation of solvents as used to extract analytes by dispersive liquid-liquid microextraction (DLLME). The method is referred to as thin film evaporation (TFE). A combination of DLLME and TFE was applied to the extraction and preconcentration of the pesticide chlorpyrifos (as a model compound) prior to analysis by ion mobility spectrometry. The ZnTiO3 nanoparticles were placed on polyacrylonitrile nanofibers which increases the porosity and surface area in the TFE process, thus causing fast and complete evaporation of solvents. The effects of sample pH value, extraction solvent and its volume, disperser solvent and volume, centrifugation time, evaporation time, and desorption temperature were optimized. The relative standard deviations of intra- and inter-day analyses were found to be 3% and 7%, respectively. The method has a linear dynamic range that covers the 0.10-3.0 μg.L−1 chlorpyrifos concentration range, the limit of detection is 0.04 μg.L−1, and the enrichment factor is up to 5400 in case of spiked samples. Some spiked field samples were analyzed and the relative recoveries ranged between 99 and 111%. When applied along with ion mobility spectrometry, the interferences caused by solvent are found to be reduced in the ionization source. This makes it possible to select a variety of solvents as needed for sample extraction.Schematic presentation of dispersive liquid-liquid microextraction (DLLME) combined with thin film evaporation (TFE) for rapid vaporization of extraction solvent: Application to the pre-concentration of chlorpyrifos prior to its quantification by corona discharge-ion mobility spectrometry (CD-IMS). [ABSTRACT FROM AUTHOR]