Developments in ultrasound-assisted microextraction techniques for isolation and preconcentration of organic analytes from aqueous samples

Review of extraction and detection techniques for the analysis of pesticide residues in fruits to evaluate food safety and make legislative decisions: Challenges and anticipations

Fruits are vital parts of the human diet because they include necessary nutrients that the body needs. Pesticide use has increased dramatically in recent years to combat fruit pests across the world. Pesticide usage during production, on the other hand, frequently results in undesirable residues in fruits after harvest. Consumers are concerned about pesticide residues since most of the fruits are directly consumed and even recommended for the patients as dietary supplements. As a result of this worry, pesticide residues in fruits are being randomly monitored to re-assess the food safety situation and make informed legislative decisions. To assess the degree of pesticide residues in fruits, a simple and quick analytical procedure is usually required. As a result, pesticide residue detection (using various analytical techniques: GC, LC and Biosensors) becomes critical, and regulatory directives are formed to regulate their amounts via the Maximum Residue Limit (MRL). Over the previous two decades, a variety of extraction techniques and analytical methodologies for xenobiotic's efficient extraction, identification, confirmation and quantification have been developed, ranging from traditional to advanced. The goal of this review is to give readers an overview of the evolution of numerous extraction and detection methods for pesticide residue analysis in fruits. The objective is to assist analysts in better understanding how the ever-changing regulatory landscape might drive the need for new analytical methodologies to be developed in order to comply with current standards and safeguard consumers.

Ultrasound-Induced Drug Release from Stimuli-Responsive Hydrogels

Stimuli-responsive hydrogel drug delivery systems are designed to release a payload when prompted by an external stimulus. These platforms have become prominent in the field of drug delivery due to their ability to provide spatial and temporal control for drug release. Among the different external triggers that have been used, ultrasound possesses several advantages: it is non-invasive, has deep tissue penetration, and can safely transmit acoustic energy to a localized area. This review summarizes the current state of understanding about ultrasound-responsive hydrogels used for drug delivery. The mechanisms of inducing payload release and activation using ultrasound are examined, along with the latest innovative formulations and hydrogel design strategies. We also report on the most recent applications leveraging ultrasound activation for both cancer treatment and tissue engineering. Finally, the future perspectives offered by ultrasound-sensitive hydrogels are discussed.

Simultaneous quantification of eleven bioactive phenolic compounds in pigeon pea natural resources and in vitro cultures by ultra-high performance liquid chromatography coupled with triple quadrupole mass spectrometry (UPLC-QqQ-MS/MS)

Bioactive phenolics primarily contribute to versatile health benefits of pigeon pea. For the first time, an UPLC-QqQ-MS/MS method was developed for the quantitative analysis of eleven bioactive phenolic compounds in pigeon pea natural resources (seeds, leaves, and roots) and in vitro cultures (calli and hairy roots). The proposed method could be achieved within 6 min of running time, and displayed the satisfactory linearity, sensitivity, precision, accuracy, and stability. According to analytical results, the distribution of eleven target compounds in different organs of pigeon pea was clarified. Also, it was surprisingly found that pigeon pea in vitro cultures exhibited superiority in contents of genistin and cajaninstilbene acid as compared with natural resources. Overall, the present work provided a rapid and sensitive analysis approach, which could be useful not only for quality control of pigeon pea natural resources, but also for applicability and safety evaluation of pigeon pea in vitro cultures.

Effervescence-Assisted Microextraction-One Decade of Developments

Dispersive microextraction techniques are key in the analytical sample treatment context as they combine a favored thermodynamics and kinetics isolation of the target analytes from the sample matrix. The dispersion of the extractant in the form of tiny particles or drops, depending on the technique, into the sample enlarges the contact surface area between phases, thus enhancing the mass transference. This dispersion can be achieved by applying external energy sources, the use of chemicals, or the combination of both strategies. Effervescence-assisted microextraction emerged in 2011 as a new alternative in this context. The technique uses in situ-generated carbon dioxide as the disperser, and it has been successfully applied in the solid-phase and liquid-phase microextraction fields. This minireview explains the main fundamentals of the technique, its potential and the main developments reported.

An ultrasound-assisted pressure-regulated solid-phase microextraction setup for fast and sensitive analysis of volatile pollutants in contaminated soil

Release of analytes from their native matrix and diffusion into the gas phase is the rate-limiting step for the sampling of volatiles in complex solid samples. This limitation is more serious in the solvent-less and solvent-free microextraction sampling strategies. In this research, a three-stage reinforced sampling strategy including high-pressure/sonication/low-pressure was introduced for fast and efficient release of analytes in soil samples. For this purpose, a novel ultrasound-assisted pressure-regulated solid-phase microextraction (UA-PR-SPME) device was developed. It was coupled with gas chromatography-flame ionization detection (GC-FID) and carried out for the determination of benzene, toluene, ethylbenzene, and xylenes (BTEX, as the model analytes) in complex solid samples. Graphene oxide/3-aminopropyltriethoxysilane (GO-APTES) nanocomposite was synthesized and used as the SPME fiber coating. Under optimal conditions, the limits of detection (LODs) were obtained 0.1-0.4 ng/g. The calibration curves were linear over the range of 2.4-5000 ng/g. Relative standard deviations (RSDs%) were calculated 5.1-7.0% (n = 6). The developed technique was employed for the analysis of BTEX in contaminated soil samples.

Recent Application of Deep Eutectic Solvents as Green Solvent in Dispersive Liquid-Liquid Microextraction of Trace Level Chemical Contaminants in Food and Water

As growing concerns on green, cost-effective, and time-saving chemistry analysis methods, deep eutectic solvents (DESs) are considered to be promising green alternatives to conventional solvents in dispersive liquid-liquid microextraction (DLLME) of trace level chemical contaminants in food and water, due to their biodegradability, low cost, and simple preparation. In the past few years, numerous innovative researches have focused on preconcentration of trace level chemical contaminants using DESs as extractant. In this context, this review aims to summarize the updated state-of-the-art effort dedicated to preconcentration of trace level chemical contaminants in food and water sample using DESs as extractants in DLLME. Furthermore, the major impact factors affecting the preconcentration efficiency and process mechanisms are thoroughly analyzed and discussed. Finally, prospects and challenges in application of DESs as solvents in DLLME to enrich trace level chemical contaminants are extensively elucidated and critically reviewed.

Ligandless, deep eutectic solvent-based ultrasound-assisted dispersive liquid-liquid microextraction with solidification of the aqueous phase for preconcentration of lead, cadmium, cobalt and nickel in water samples

A green and efficient sample preparation method using a deep eutectic solvent-based ultrasounds-assisted dispersive liquid-liquid microextraction with solidification of the aqueous phase followed by high performance liquid chromatography analysis was developed for preconcentration and determination of heavy metals in environmental samples. In the proposed method, a novel, low density deep eutectic solvent was prepared by mixing trihexyl(tetradecyl)phosphonium chloride and thiosalicylic acid at a molar ratio of 1:2 and used both as an extractant and complexing agent. Ultrasound was used to disperse the extractant in the aqueous phase of the sample. Then, the phases were separated by centrifugation, after which the aqueous phase was frozen and the surface extractant phase was dissolved in a small volume of acetonitrile and subjected to liquid chromatographic analysis. The proposed method provided precisions (relative standard deviation, n = 5) in the range of 2.6-4.7%. The limit of detection were 0.05, 0.13, 0.06, and 0.11 µg/L for Pb(II), Cd(II), Co(II), Ni(II), respectively. The enhancement factors were equal to 154, 159, 162, and 158 for lead(II), cadmium(II), cobalt(II), and nickel(II), respectively. The accuracy of the proposed method was evaluated using certified reference materials (CA011b - hard drinking water, NIST 1643e - trace elements in water, TMRAIN-04 - simulated rain sample).

Ultrasound-promoted dispersive micro solid-phase extraction of trace anti-hypertensive drugs from biological matrices using a sonochemically synthesized conductive polymer nanocomposite

In this work, a rapid and efficient procedure named ultrasound meliorated dispersive micro solid-phase extraction followed by high performance liquid chromatography-ultra violet detection (US-D-μSPE-HPLC-UV) was developed for the pre-concentration of the main trace anti-hypertensive drugs in complex matrices. The basis of this procedure was a polypyrrole-sodium dodecylbenzenesulfonate/zinc oxide (PPy-DBSNa/ZnO) nanocomposite. It was readily synthesized by the impressive way of in situ sonochemical oxidative polymerization in the presence of some additives such as FeCl₃ and DBSNa, ultimately leading to the effective coating of PPy on the ZnO nanoparticle cores. Characterization of the proposed nanosorbent was performed by different techniques such as FESEM, XRD,EDX, and TGA, confirming the high quality and proper physico-chemical properties of the proposed sorbent. In order to better investigate the input variables, the central composite design (CCD) combined with the desirability function (DF) was utilized. The enriched optimum conditions consisted of the initial pH value of 11.8, 15mg of the PPy-DBSNa/ZnO nanocomposite, a sonication time of 4.6min, and 100μL of methanol, resulting in maximum responses at a relatively low extraction time with a logical DF. Under the optimum conditions, good linearity (5-5000, 2.5-3500, and 2.5-3000ngmL^-1 for metoprolol, propranolol, and carvedilol, respectively, with the correlation of determinations (R²s) higher than 0.99), low limits of detection (LODs) (0.8-1.5ngmL^-1), proper repeatabilities (relative standard deviation values (RSDs) below 6.3%, n=3), reasonable enrichment factors (EFs) (60-72), and good extraction recoveries (ERs) (higher than %75) were obtainable. These appropriate validations corroborated a good effectiveness of ultrasonic waves in the achievement of a supreme solid phase as well as a facile and efficient microextraction of the low therapeutic concentrations in human plasma and urine samples.

Emerging trends in photodegradation of petrochemical wastes: a review

Various human activities like mining and extraction of mineral oils have been used for the modernization of society and well-beings. However, the by-products such as petrochemical wastes generated from such industries are carcinogenic and toxic, which had increased environmental pollution and risks to human health several folds. Various methods such as physical, chemical and biological methods have been used to degrade these pollutants from wastewater. Advance oxidation processes (AOPs) are evolving techniques for efficient sequestration of chemically stable and less biodegradable organic pollutants. In the present review, photocatalytic degradation of petrochemical wastes containing monoaromatic and poly-aromatic hydrocarbons has been studied using various heterogeneous photocatalysts (such as TiO₂, ZnO and CdS. The present article seeks to offer a scientific and technical overview of the current trend in the use of the photocatalyst for remediation and degradation of petrochemical waste depending upon the recent advances in photodegradation of petrochemical research using bibliometric analysis. We further outlined the effect of various heterogeneous catalysts and their ecotoxicity, various degradation pathways of petrochemical wastes, the key regulatory parameters and the reactors used. A critical analysis of the available literature revealed that TiO₂ is widely reported in the degradation processes along with other semiconductors/nanomaterials in visible and UV light irradiation. Further, various degradation studies have been carried out at laboratory scale in the presence of UV light. However, further elaborative research is needed for successful application of the laboratory scale techniques to pilot-scale operation and to develop environmental friendly catalysts which support the sustainable treatment technology with the "zero concept" of industrial wastewater. Nevertheless, there is a need to develop more effective methods which consume less energy and are more efficient in pilot scale for the demineralization of pollutant.

A green ultrasonic-assisted liquid-liquid microextraction based on deep eutectic solvent for the HPLC-UV determination of ferulic, caffeic and cinnamic acid from olive, almond, sesame and cinnamon oil

A simple, inexpensive and sensitive ultrasonic-assisted liquid-liquid microextraction method based on deep eutectic solvent (UALLME-DES) was used for the extraction of three phenolic acids (ferulic, caffeic and cinnamic) from vegetable oils. In a typical experiment, deep eutectic solvent as green extraction solvent was added to n-hexane (as a typical oil medium) containing target analytes. Subsequently, the extraction was accelerated by sonication. After the extraction, phase separation (DES rich phase/n-hexane phase) was performed by centrifugation. DES rich phase (lower phase) was withdrawn by a micro-syringe and submitted to isocratic reverse-phase HPLC with UV detection. Under optimum conditions obtained by response surface methodology (RSM) and desirability function (DF), the method has good linear calibration ranges (between 1.30 and 1000 µg L(-1)), coefficients of determination (r(2)>0.9949) and low limits of detection (between 0.39 and 0.63 µg L(-1)). This procedure was successfully applied to the determination of target analytes in olive, almond, sesame and cinnamon oil samples. The relative mean recoveries ranged from 94.7% to 104.6%.

Simultaneous Determination of Four Plant Hormones in Soil by Ultrasound-Assisted Ionic Liquid Based Dispersive Liquid-Liquid Microextraction

An ultrasound-assisted ionic liquid based dispersive liquid-liquid microextraction (UA-IL-DLLME) was developed for the determination of four plant hormones (6-benzyladenine (6-BA), kinetin (6-KT), 2, 4-dichlorophenoxy acetic acid (2, 4-D) and uniconazole (UN)) in soil, using high performance liquid chromatography (HPLC)-diode array detection (DAD). Several important parameters including the type and volume of extraction solvent, the volume of disperser solvent, ultrasound time, pH of the solution and salt effect were studied and optimized. Under optimum conditions, the limits of detections (LODs) for the target analytes were in the range of 0.002-0.01 μg g-1. And satisfactory recoveries of the target analytes in the soil samples were 79.3-96.7 %, with relative standard deviations (RSD, n=5) that ranged from 4.3 to 6.7%.