Alternative Green Preconcentration Approach Based on Ultrasound-Assisted Surfactant-Enhanced Emulsification Microextraction and HPLC for Determination of Benzimidazole Anthelmintics in Milk Formulae

An alternative green microextraction method based on ultrasound-assisted surfactant-enhanced emulsification microextraction (UASEME) using a low-density extraction solvent coupled with HPLC has been developed for preconcentration and determination of six benzimidazole anthelmintics, namely, oxfendazole, albendazole, mebendazole, flubendazole, fenbendazole, and niclosamide. The separation was achieved within 12 min, using an Inertsil^® C18 column (4.6 × 150 mm, 5.0 µm), with a gradient mobile phase of acetonitrile and 0.1 % (v/v) formic acid. Under the optimum UASEME conditions using Tergitol^® TMN-6 and 1-octanol as emulsifier and extraction solvent, respectively, linearity was in the range of 0.5–5,000 μg L⁻¹ with the coefficients of determination (R ²) ranging from 0.9959 to 0.9999. Enrichment factors were obtained up to 89, corresponding to limits of detection ranging from 0.50 to 6.00 µg L⁻¹. Intra-day (n = 8) and inter-day (n = 3 × 3) precisions were obtained with relative standard deviations for retention time and peak area of lower than 2 and 15 %, respectively. The proposed method was successfully applied to determine the target benzimidazoles in milk formulae.

     

Simple magnetization of Fe3O4/MIL‐53(Al)‐NH2 for a rapid vortex‐assisted dispersive magnetic solid‐phase extraction of phenol residues in water samples

The present work describes a simple route to magnetize MIL‐53(Al)‐NH₂ sorbent for rapid extraction of phenol residues from environmental samples. To extend the applications and performances of the metal‐organic frameworks in the field of adsorption materials, we combined the properties of metal‐organic frameworks and magnetite to decrease the extraction time and simplify the extraction process as well. In this study, a simple and quick vortex‐assisted dispersive magnetic solid phase extraction method for the extraction of ten United States Environmental Protection Agency's priority phenols from water samples prior to analysis by high‐performance liquid chromatography with photodiode array detection was proposed. The developed method exhibits a rapid enrichment of the target analytes within 10 s for extraction and 10 s for desorption. Low detection limits of 1.8‐41.7 µg/L and quantitation limits of 6.0‐139.0 µg/L with the relative standard deviations for intra‐ and interday analyses less than 12% were achieved. Satisfactory recoveries in the range of 80‐111% with the relative standard deviations less than 11% demonstrated that Fe₃O₄/MIL‐53(Al)‐NH₂ is promising sorbent in the field of magnetic solid‐phase extraction for environmental samples.     

Amine-Functionalized Metal–Organic Framework as a New Sorbent for Vortex-Assisted Dispersive Micro-Solid Phase Extraction of Phenol Residues in Water Samples Prior to HPLC Analysis: Experimental and Computational Studies

Metal–organic frameworks (MOFs) are a new class of hybrid inorganic–organic microporous crystalline materials, which possess unique properties such as high surface area, tunable pore size, and good thermal stability. These unique characteristics make MOFs interesting targets for sample pretreatment. In this work, MIL-53 material based on aluminum and containing amine functional groups (NH₂-MIL-53(Al)) was synthesized and applied as an efficient sorbent for development of vortex-assisted dispersive micro-solid phase extraction for eight United States Environmental Protection Agency’s priority phenols from aqueous samples prior to analysis by high-performance liquid chromatography with photodiode-array detection. A simple extraction process was designed. The parameters affecting the extraction efficiency, such as amount of sorbent, extraction time, type of desorption solvent and its volume were investigated. The good linearity in the concentration range of 0.0015–10.0000 μg mL^?1 with the coefficients of determination of greater than 0.9929, low limits of detection (0.0004–0.0133 μg mL^?1) and relative standard deviations of lower than 10% were obtained. The proposed method has been successfully applied to the determination of phenol compounds in different water sample matrices including treated water, waste water, river water, sea water, lake water, drinking water and tap water. In addition, computational simulation was performed to predict the adsorption ability of NH₂-MIL-53(Al) towards the studied phenolic compounds. The computational results were in agreement with the experimental studies and it has been proved that NH₂-MIL-53(Al) is promising for enrichment of phenolic pollutants.     

Alternative Green Preconcentration Approach Based on Ultrasound-Assisted Surfactant-Enhanced Emulsification Microextraction and HPLC for Determination of Benzimidazole Anthelmintics in Milk Formulae

An alternative green microextraction method based on ultrasound-assisted surfactant-enhanced emulsification microextraction (UASEME) using a low-density extraction solvent coupled with HPLC has been developed for preconcentration and determination of six benzimidazole anthelmintics, namely, oxfendazole, albendazole, mebendazole, flubendazole, fenbendazole, and niclosamide. The separation was achieved within 12 min, using an Inertsil^® C18 column (4.6 × 150 mm, 5.0 µm), with a gradient mobile phase of acetonitrile and 0.1 % (v/v) formic acid. Under the optimum UASEME conditions using Tergitol^® TMN-6 and 1-octanol as emulsifier and extraction solvent, respectively, linearity was in the range of 0.5–5,000 μg L^?1 with the coefficients of determination (R ²) ranging from 0.9959 to 0.9999. Enrichment factors were obtained up to 89, corresponding to limits of detection ranging from 0.50 to 6.00 µg L^?1. Intra-day (n = 8) and inter-day (n = 3 × 3) precisions were obtained with relative standard deviations for retention time and peak area of lower than 2 and 15 %, respectively. The proposed method was successfully applied to determine the target benzimidazoles in milk formulae.     

Exploiting a combined computational/experimental sorbent-injection vortex-assisted dispersive microsolid-phase extraction for chromatographic determination of priority phenolic pollutants in water samples

An amine-functionalized metal–organic framework based on aluminum (NH₂-MIL-53(Al)) was synthesized and employed as a sorbent for the extraction of phenolic pollutants. A new designed sorbent-injection vortex-assisted dispersive microsolid-phase extraction was proposed in which the sorbent suspension was simply injected into the sample solution. Herein the experimental parameters that affected the extraction efficiency for the target analytes were optimized, including volume of sorbent suspension, vortex agitation time, eluent type and its volume, and sample volume. Good linearity was obtained in the concentration range of 0.1–10.0 mg L^?1 with the correlation coefficients in the range of 0.9970–0.9981. The LODs and LOQs were in the ranges of 0.030–0.055 and 0.090–0.150 mg L^?1, respectively. The results of the intra- and inter-day experiments showed good precision of peak area with the relative standard deviation (RSD) values of better than 5.82 and 7.85%, respectively. The developed method has been successfully applied to determine phenolic residues in water samples. The satisfactory recoveries were obtained in the range of 83.0–122.4% with the RSDs of less than 12.9%. In addition, molecular docking was performed to predict the adsorption ability of NH₂-MIL-53(Al) sorbent toward the target analytes. The computational results were in good agreement with data obtained experimentally.