Switchable hydrophilic solvent-based dispersive liquid-liquid microextraction coupled with high-performance liquid chromatography for the determination of four types of sulfonylurea herbicides in soils

Eco-friendly solvents in liquid-liquid microextraction techniques for biological and environmental analysis: a critical review

In recent years, green solvents have emerged as promising alternatives in the field of analytical chemistry, replacing conventional organic solvents known for their toxicity, volatility, and flammability. The combination of these solvents with liquid-liquid microextraction techniques has facilitated the development of simpler, faster, more economical, and environment-friendly methodologies for the analysis of samples of varying complexity. This review discusses the fundamental physicochemical properties and advantages of using deep eutectic solvents, ionic liquids, switchable-hydrophilicity solvents, supramolecular solvents, and surfactants as extractants. Furthermore, analytical methods based on liquid-liquid microextraction techniques developed in the last 5 years for the determination of organic compounds and metals in biological and environmental samples are presented and discussed, highlighting their applications and benefits to improve analytical performance and sustainability.

Synthesis and characterization of pH-responsive deep eutectic solvent followed by HPLC for trace determination of bisphenol A in water samples

A microextraction based on pH-responsive deep eutectic solvent combined with high-performance liquid chromatography was developed for the separation, preconcentration, and determination of bisphenol A in water samples. Five deep eutectic solvents were prepared using thymol (hydrogen bond acceptor) and 6-, 8-, 9-, 10-, and 12-carbon carboxylic acids (hydrogen bond donor), and were used as extraction solvent. Herein, by alkalinizing the environment, phase transition takes place, and by adding acid, phase separation and extraction of analytes occur simultaneously. Some important parameters on the extraction such as deep eutectic solvent type, molar ratio of deep eutectic solvent components, deep eutectic solvent volume, potassium hydroxide concentration, hydrochloric acid volume, extraction time, and salt addition were optimized. Under the optimum conditions, intra- and interday precisions of the method based on seven replicate measurements of 10 μg L-1 of bisphenol A in water samples were 2.2% and 4.3%, respectively. The analytical performance of the method showed linearity over the concentration of 0.05-50 μg L-1 with the detection limit of 0.02 μg L-1 . The accuracy of the method was confirmed by spiking different concentrations of bisphenol A in real water samples and obtaining relative recoveries in the range of 92.5%-105.2%.

A Review on Recent Innovations of Pretreatment and Analysis Methods for Sulfonylurea Herbicides

Sulfonylurea herbicides (SUHs) are widely used in agriculture because of their low dosage, low cost, and high selectivity. However, due to improper use and lack of effective management, their residues pose a threat to the human health through environment and food pollution. Therefore, there is a need for simple, quick, economical, and effective methods to analyze SUHs in plant-derived foods, crops, and environmental samples. The present article presents a comprehensive review of the pretreatment and analytical technologies used for SUHs in various sample matrices, focusing on the developments since 2010. The main pretreatment methods include liquid-liquid extraction, solid-phase extraction, QuEChERS, and different microextraction methods, whereas analytical methods mainly include liquid chromatography coupled with different detectors, capillary electrophoresis, among others. In addition, the present study also compared the advantages and disadvantages of the methods and the future development is prospected.

Current Sample Preparation Methods and Analytical Techniques for the Determination of Synthetic Antioxidants in Edible Oils

Synthetic antioxidants play a critical role in the storage and process of edible oil due to that they can retard lipid oxidation, maintain the quality of oils, and prolong the shelf life. However, a series of studies have proved the potential risks of synthetic antioxidants for human health when consumed in excess, and many countries have established the permitted amounts of synthetic antioxidants in oils. Thus, the accurate quantification of synthetic antioxidants in edible oils is necessary, and there have developed various analytical methods involved in chromatographical, electrochemical, and spectroscopic methods. Owing to the complex matrix and the incompatibility between the oil sample and the detection instrument, sample preparation is usually adopted prior to the instrument detection to improve the detection effectiveness. The current review aims to provide a comprehensive overview of the recently developed sample preparation methods and analytical techniques applied to determine synthetic antioxidants in edible oils from 2010 to present, with emphasis on the sample preparation methods combined with separation-based analytical techniques such CE and LC with various detectors. The advantages and limitations of some typical analytical methods are discussed and some insights in the future perspectives are also provided in this review. This article is protected by copyright. All rights reserved.