Streamlined Water-Leaching Preconcentration Method As a Novel Analytical Approach and Its Coupling to Dispersive Micro-Solid-Phase Extraction Based on Synthetically Modified (Fe/Co) Bimetallic MOFs.

The streamlined water-leaching preconcentration method is introduced as a novel preconcentration method in this study. The approach has many benefits including low consumption of organic solvent and deionized water and operation time, energy-saving, no need for dispersion or evaporation, and implementation of more efficient preconcentration. Also, a methodological study was done on the synthesis of (Fe/Co) bimetallic-organic framework that eased the synthesis procedure, decreased its time, and enhanced its analytical performance by increasing its surface area, total pore volume, and average pore diameter parameters. To perform the extraction, bi-MOF particles were added into the solution of interest enriched with sodium sulfate. After vortexing to adsorb the analytes, centrifugation isolated the sorbent particles. A microliter-volume of acetonitrile and 1,2-dibromoethane mixture was used for desorption aim via vortexing. After the separation of the organic phase and transferring it into a conical bottom glass test tube, a milliliter volume of sodium chloride solution was applied to leach the organic phase. A gas chromatograph equipped with a flame ionization detector was applied for the injection of the extracted phase. The method was applied for the extraction and preconcentration of some pesticides from juice samples. Wide linear ranges (5.44-1600 µg L-1), low relative standard deviations (3.1-4.5% for intra- (n = 6) and 3.5-5.2% for interday (n = 4) precisions), high extraction recoveries (61-95%), enrichment factors (305-475), and low limits of detection (0.67-1.65 µg L-1) and quantification (2.21-5.44 µg L-1) were obtained for the developed method.

Extraction and preconcentration of parabens from the human follicular fluid through dispersive micro solid phase extraction using microporous MIL-68 (In) followed by in-situ effervescence-boosted dispersive liquid-liquid microextraction.

For the first time in this study, a microextraction method was developed to perform follicular fluid safety assessment analysis. The drastic importance of follicular fluid safety on the proper nourishment and development of oocytes caused the development of the present method. Since women are regularly exposed to parabens through cosmetics, healthcare, and hygienic products, the infection of body fluids is probable in long-term exposures. Also, for the first time, MIL-68 (In) was applied in an analytical method. Moreover, a new method called in-situ effervescence-boosted dispersive liquid-liquid microextraction was adopted for the simultaneous derivatization and preconcentration of the target parabens. To perform the method, 25 mg of MIL-68 (In) was dispersed into the solution of follicular fluid by vortexing. Then, 1.0 mL of 2-propanol was used to elute the analytes from the absorbent via vortexing. The analyte-enriched organic phase was mixed with 100 µL of acetic anhydride (derivatization agent) and 27 µL 1,2-dibromoethane (extraction solvent) which was swiftly injected into a sodium carbonate solution. Following the centrifugation, the extraction solvent was sedimented at the bottom of a conical bottom glass test tube and an aliquot of it was injected into a gas chromatograph equipped with a flame ionization detector. Wide linear ranges (120-25000 µg L-1), satisfactory extraction recoveries (31-79%) and enrichment factors (31-79), and appreciable limits of detection (7-36 µg L-1) and quantification (25-120 µg L-1) were recorded. The high surface area of MIL-68 (In) (608.82 m2 g-1) and its significantly low average pore diameter (13.829 A°) provide an ideal platform for the extraction of parabens from the complex matrix of follicular fluid.

MIL-68 (Ga) for the extraction of derivatized and non-derivatized parabens from healthcare products.

This study was the first-ever attempt to apply MIL-68 (Ga) in developing an analytical method. The method extracts and preconcentrates some parabens from mouthwash and hydrating gel samples. The variable extraction parameters were optimized, and the figures of merit were documented. Avogadro software was used besides discussing intermolecular interactions to clarify the absorption process. ComplexGAPI software was also exploited to assess the greenness of the method. After the derivatization of the parabens using acetic anhydride in the presence of sodium carbonate, sodium chloride was added to the solution and vortexed to dissolve. A few milligrams of MIL-68 (Ga) were added into the solution and vortexed. Centrifugation separated the analyte-loaded absorbent, which was treated with mL volume of methanol through vortexing for desorption aim. A few microliters of 1,2-dibromoethane were merged with the methanolic phase and injected into a sodium chloride solution. One microliter of the extracted phase was injected into a gas chromatograph equipped with a flame ionization detector. High enrichment factors (200-330), reasonable extraction recoveries (40-66%), wide linear ranges (265-30,000 µg L-1), and appreciable coefficients of determination (0.996-0.999) were documented. The applicability of dispersive solid phase extraction for extracting polar analytes, imposing no additional step for performing derivatization, the capability of MIL-68 (Ga) for the absorption of both derivatized and non-derivatized parabens, the use of only 10 mg absorbent, and one-pot synthesis besides no high temperature or long reaction time in the sorbent provision are the highlights of the method.

NiGA MOF-based dispersive micro solid phase extraction coupled to temperature-assisted evaporation using low boiling point solvents for the extraction and preconcentration of butylated hydroxytoluene and some phthalate and adipate esters.

The first-ever attempt to apply nickel gallic acid metal-organic framework (NiGA MOF) in analytical method development was done in this research by the extraction of some plasticizers from aqueous media. The greenness of the method is owing to the use of gallic acid and nickel as safe reagents and water as the safest solvent. Low boiling point solvents were applied as desorption solvents that underwent temperature-assisted evaporation in the preconcentration step. Performing the evaporation using a low-temperature water bath for a short period of time streamlines the preconcentration section. Into the solution of interest enriched with sodium sulfate, a mg amount of NiGA MOF was added alongside vortexing to extract the analytes. Following centrifugation and discarding the supernatant, a µL level of diethyl ether was added onto the analyte-loaded NiGA MOF particles and vortexed. The analyte-enriched diethyl ether phase was transferred into a conical bottom glass test tube and located in a water bath set at the temperature of 35 °C under a laboratory hood. After the evaporation, a µL level of 1,2-dibromoethane was added to the test tube and vortexed to dissolve the analytes from the inner perimeter of the tube. One microliter of the organic phase was injected into a gas chromatograph equipped with flame ionization detection. Appreciable extraction recoveries (61-98%), high enrichment factors (305-490), low limits of detection (0.80-1.74 µg L-1) and quantification (2.64-5.74 µg L-1), and wide linear ranges (5.74-1000 µg L-1) were obtained at the optimum conditions.

Introduction of a new and safe synthesis procedure for Ni-MOF-I in aqueous solution and its application for the extraction of some pesticides from different beverages.

For the first time, this research introduces an analytical application of Ni-MOF-I, which was used as an adsorbent in a dispersive micro solid phase extraction procedure followed by dispersive liquid-liquid microextraction for the extraction and preconcentration of seven pesticides from different fruit juices. Also, Ni-MOF-I was synthesized by a new and green method with many advantages over the previously published synthesis procedures. For example, effortless and green synthesis, no need for autoclaves and ovens, and elimination of organic solvent usage are the main highlights. The synthesized Ni-MOF-I was characterized by applying nitrogen adsorption/desorption, energy-dispersive X-ray, scanning electron microscopy, Fourier transform infrared spectrophotometry, and X-ray diffraction analyses. The studied pesticides were extracted and preconcentrated by the proposed method. Then, the extracted analytes in the sedimented organic phase were injected into a gas chromatography-flame ionization detector. Acceptable analytical results such as low limits of detection (0.15-0.60 µg L-1) and quantification (0.50-2.0 µg L-1), reasonable extraction recoveries (51-80%), high enrichment factors (255-400), satisfactory relative standard deviation values of 4.8-7.2% (intra-day precision, n = 6) and 5.3-7.5% (inter-day precision, n = 4), and wide linear ranges were obtained. The proposed method can be introduced as an effective analytical technique based on Ni-MOF-I for the analysis of different pesticides in fruit beverages.

An all-embracing analytical method comprising modified QuEChERS-dispersive micro-solid-phase extraction-dispersive liquid-liquid microextraction using FeGA MOF for the extraction and preconcentration of pesticides simultaneously from juice and flesh of watermelon.

For the first time, a comprehensive analytical method based on a one-dimensional metal-organic framework comprising "quick, easy, cheap, effective, rugged, and safe-dispersive micro solid phase extraction-dispersive liquid-liquid microextraction" was introduced in this research. Moreover, the first-ever attempt was accomplished to apply the iron-gallic acid metal-organic framework in analytical method development. The goal of the research was to analyze the pesticide content of watermelon comprehensively in its flesh and juice. Based on this, comprehensive and reliable food safety monitoring can be done. Initially, pesticides of the watermelon flesh were extracted using an mL volume of acetonitrile by vortexing. At the same time, the pesticides of watermelon juice were extracted from the juice matrix onto the sorbent particles facilitated by vortexing. The obtained acetonitrile phase was also used to desorb the analytes from the sorbent surface by vortexing. As a result, the pesticide content of both juice and flesh was extracted into the acetonitrile. The pesticide-enriched acetonitrile was then used as the disperser solvent by being merged with µL level of 1,2-dibromoethane and injection into deionized water. A cloudy solution was created as the result. Centrifugation triggered extractant at the bottom of the conical glass test tube and an aliquot of it was injected into a gas chromatograph equipped with a flame ionization detector. High enrichment factors (210-400), appreciable extraction recoveries (42-80%), wide linear ranges (3.20-1000 µg kg-1), relative standard deviations in the ranges of 3.6-4.4% for intra- (n = 6) and 4.4-5.3% for inter-day (n = 3) precisions, and low limits of detection (0.43-0.97 µg kg-1), and quantification (1.42-3.20 µg kg-1) were obtained by the application of the developed method.

Pesticide content analysis of red and yellow watermelon juices through a solid phase microextraction using a green copper-based metal-organic framework synthesized in water followed by a liquid phase microextraction procedure.

For the first time, this survey demonstrates the use of MIL-53 (Cu) in an analytical method for the detection and determination of some pesticides through their extraction and preconcentration from red and yellow watermelon juices. The other predominance of the research is using a green metal-organic framework that is based on copper and synthesized in deionized water. After conducting the synthesis process, Fourier transform infrared spectrophotometry, X-ray diffraction, scanning electron microscopy, and nitrogen adsorption/desorption analyses were carried out. In the analytical approach, the samples were accompanied by the sorbent addition and vortexed to facilitate the sorption of the analytes onto the sorbent and then centrifuged to be settled down. Then, the analyte-loaded sorbent particles were treated with mL-volume of acetonitrile and subjected to vortexing and centrifugation. Eventually, the eluate was mixed with µL-level of carbon tetrachloride and instantly injected into deionized water. The resulting milky solution was centrifuged and consequently, the sedimentation of the organic phase occurred at the bottom of the conical glass test tube. An aliquot of it was injected into a gas chromatograph equipped with flame ionization detector. Low limits of detection (0.85-1.24 µg L-1) and quantification (2.80-4.10 µg L-1), high enrichment factors (275-330), and reasonable extraction recoveries (55-66%) were the main achievements of the presented method. It is worthwhile to be confessed that chlorpyrifos was detected in red watermelon juice at a concentration of 27 ± 2 µg L-1.

Combination of a dispersive solid phase extraction method based on octadecylamine modified magnetic nanoparticles with dispersive liquid-liquid microextraction for the extraction and preconcentration of pesticides.

In the present work, a new and efficient sorbent has been prepared using the co-precipitation method for magnetic dispersive solid phase extraction followed by dispersive liquid-liquid microextraction. This method was used for the extraction and preconcentration of some widely-used pesticides (chlorpyrifos, haloxyfop-R-methyl, oxadiazon, diniconazole, clodinafop-propargyl, fenpropathrin, and fenoxaprop-P-ethyl) from fruit juices prior to their determination by gas chromatography-flame ionization detection. The sorbent was prepared by octadecylamine co-precipitation with Fe3O4. In the first step, mg amount of the magnetic sorbent was spread into an aqueous sample solution including the selected analytes and vortexed. Then the analytes were eluted with acetonitrile from the surface of the nanoparticles separated with an external magnetic field from the aqueous solution. In the second step, the obtained eluent was mixed with an extraction solvent (chloroform) at the µL-level and rapidly injected into deionized water. After centrifugation, an aliquot of the sedimented phase was injected into the separation system. Experimental parameters which control the performance of both steps were investigated and optimized. Using optimum extraction conditions, the proposed method provided low limits of detection (0.23-0.41 µg L-1) and quantification (0.81-1.3 µg L-1), high enrichment factors (353-443), acceptable extraction recoveries (70-88%), and satisfactory relative standard deviations (≤6%) for intra- (n = 6) and inter-day (n = 4) precisions at a concentration of 30 µg L-1 of each pesticide.

Development of a method based on dispersive liquid-liquid microextraction followed by partial vaporization of the extract for ultra-preconcentration of some pesticide residues in fruit juices.

A new simple and efficient method has been developed for the ultra-preconcentration of multiclass pesticide residues including penconazole, chlorpyrifos, ametryn, clodinafop-propargyl, diniconazole, oxadiazon, and fenpropathrin from some fruit juice samples based on evaporation of the sedimented organic phase obtained from dispersive liquid-liquid microextraction. The enriched target analytes were analyzed by gas chromatography-flame ionization detection. In the microextraction procedure, a mixture of iso-propanol as a disperser and 1,2-dibromoethane as an extraction solvent is quickly injected into an aqueous phase containing the analytes and centrifuged. Afterward, the sedimented phase is transferred into a special shaped vaporization vessel and vaporized with nitrogen gas stream until remaining about 2 µL of it. Eventually, 1 µL of the remained sedimented phase is removed and analyzed by separation system. The optimum extraction and disperser solvents were found to be 1,2-dibromoethane and iso-propanol, respectively. In addition, the optimum pH range was 6-8, and nitrogen gas stream at a flow rate of 90 mL min-1 in a downward oriented vessel was applied. Eventually, the limits of detection and quantification were obtained in the ranges of 45-78 and 149-261 ng L-1, respectively. Relative standard deviations at the concentrations of 300, 500 and 1000 ng L-1 of each analyte were ranged between 2.2% and 5.8% for intra-day (n = 6) precision. Inter-day (n = 3) precision at a concentration of 500 ng L-1 of each analyte was obtained in the range of 4.9-7.1%. In addition, enrichment factors and extraction recoveries were ranged from 1382-2246 and 55-89%, respectively. Finally, the method was successfully utilized in analysis of the target pesticides in the selected juices.