Development of a surfactant-assisted dispersive solid phase extraction using deep eutectic solvent to extract four tetracycline antibiotics residues in milk samples

Green hairy basil seed mucilage biosorbent for dispersive solid phase extraction enrichment of tetracyclines in bovine milk samples followed by HPLC analysis

Unmodified hairy basil seed mucilage (Ocimum basilicum L.), with attractive features as structural functionality and adsorption capacity, was employed as a green biosorbent for dispersive solid phase extraction and enrichment of oxytetracycline, tetracycline, and doxycycline before quantitation by HPLC-UV for the first time. Hairy basil crushed seed increased the contacting surface area and was completely dispersed in the sample solution to extract tetracyclines under acidic condition with the assistance of ultrasonic waves. The analytes in the extraction phase were separated on a C18 column under isocratic condition with a mobile phase consisted of acetonitrile and trifluoroacetic acid. Influence of chemical and physical variables on the extraction efficiency of the developed method was investigated and optimized systematically. Under the optimal condition of all experimental parameters, good linear ranges were obtained at 15.0-500 μg L-1 for tetracyclines with determination coefficients more than 0.9994. Limits of detection (LODs) and limits of quantitation (LOQs) ranged 5.0-7.0 and 15.0 μg L-1, respectively. Relative standard deviations (RSDs) of the proposed method at 100 and 300 μg L-1 for TCs were less than 13 % and 10 %, respectively with percentage TC recoveries from spiked standard ranging 83.1-109.9 %. This simple, reliable, cost-effective, and environmentally friendly method was successfully applied for the analysis of tetracycline residues in milk. The greenness of the proposed method was assessed using the Analytical Eco-Scale and AGREE protocol.

In-situ sorbent formation for the extraction of pesticides from honey

An organic polymer was re-precipitated in solution to use as an adsorbent in dispersive solid phase extraction of some pesticides from honey samples prior to their determination by high performance liquid chromatography-tandem mass spectrometry. In this approach, different deep eutectic solvents were prepared using lysine and their ability in elution of the analytes from the adsorbent surface were tested. A diluted honey solution was transferred into a glass test tube and then a solution of polystyrene dissolved in dimethylformamide was injected into the solution. By doing this, polystyrene re-precipitated in the solution and dispersed in whole parts of it as many tiny particles. Then the mixture was centrifuged and the adsorbed analytes on the particles were eluted using a proper hydrophilic deep eutectic solvent. Central composite design approach was used for optimization of effective parameters. The limits of detection and quantification were in the ranges of 0.06-0.20 and 0.22-0.69 ng/g, respectively. The calibration curves obtained by matrix-matched standard solutions were linear in the range of 0.69-500 ng/g with coefficient of determinations ≥0.9962. The method provided high extraction recoveries (70-99%) and enrichment factors (140-198), and an acceptable precision (relative standard deviations ≤7.1%). This article is protected by copyright. All rights reserved.

Evaluation of three sorbent-phase extraction techniques based on hyper-crosslinked polymer for the extraction of five endocrine disrupters in water

A series of low-cost hyper-crosslinked polymers were prepared by an easy one-step Friedel-Crafts reaction. The synthesized hyper-crosslinked polymers exhibited remarkably porous structure, large surface area, and hydroxyl groups, which can be employed as an ideal adsorbent material for novel sorbent-phase extraction techniques. Based on this, using hyper-crosslinked polymers as sorbent and coating, three novel extraction methods, including micro-solid-phase extraction, dispersive solid-phase extraction, and solid-phase microextraction, were explored and evaluated for simultaneous measurement of five endocrine-disrupting compounds (triclosan and bisphenol A, tetrabromobisphenol A, tetrabromobisphenol A bisallylether, and tetrabromobisphenol A bis(2,3-dibromopropyl ether)) in environment water prior to high-performance liquid chromatography-ultraviolet. The influence of experimental parameters on three extraction techniques such as extraction time, the amount of hyper-crosslinked polymers, extraction temperature, ionic strength, and desorption conditions were optimized. Three previously mentioned methods provided limits of detection ranging from 0.01 to 0.05 μg/L, and high recoveries (85-99%) with relative standard deviations of 1.7-5.6%. This study presented the merits and disadvantages of three proposed extraction methods and their potential for effective monitoring of hazardous pollutants in real water samples.