Direct immersion single drop micro-extraction method for multi-class pesticides analysis in mango using GC-MS

Controllable synthesis of flower-like hierarchical porous TiO2 at room temperature and its affinity application

Flower-like particles have attracted much attention due to their efficient surface accessible sites and unique hierarchical porous structure. However, their synthesis is usually challenging and requires complex procedures. Herein, we present a simple method for rapid preparation of flower-like hierarchical porous TiO2 (FHP-TiO2) at room temperature for the first time. This method can accurately control the size of FHP-TiO2 from 150 nm to 400 nm by combining co-assembly and Stober reaction. The formation mechanism and influencing factors of FHP-TiO2 were systematically investigated, and its excellent metal oxide affinity was confirmed by theoretical calculations. Due to its hierarchical porous structure, large surface area and high specificity performance, FHP-TiO2 served as an appealing restricted-access adsorbent for specific and efficient enrichment of molecules with phosphate groups in a complex sample matrix, thereby realizing the quantitative analysis of these important biomolecules by coupling with high performance liquid chromatography-tandem mass spectrometry (HPLC-MS/MS). Moreover, compared with other morphologies (rough surface, and hollow dendritic and mesoporous structure) of TiO2 and flower-like SiO2, FHP-TiO2 showed the best affinity binding ability. This research not only presents a novel approach for tunable room-temperature synthesis of FHP-TiO2 with different sizes, but also expands the application of FHP-TiO2 as an appealing sample-enricher for food safety monitoring and early disease diagnosis.

Deep eutectic solvents for the determination of endocrine disrupting chemicals

The harmful effects of endocrine disrupting chemicals (EDCs) to humans and other organisms in the environment have been well established over the years, and more studies are ongoing to classify other chemicals that have the potential to alter or disrupt the regular function of the endocrine system. In addition to toxicological studies, analytical detection systems are progressively being improved to facilitate accurate determination of EDCs in biological, environmental and food samples. Recent microextraction methods have focused on the use of green chemicals that are safe for analytical applications, and present very low or no toxicity upon disposal. Deep eutectic solvents (DESs) have emerged as one of the viable alternatives to the conventional hazardous solvents, and their unique properties make them very useful in different applications. Notably, the use of renewable sources to prepare DESs leads to highly biodegradable products that mitigate negative ecological impacts. This review presents an overview of both organic and inorganic EDCs and their ramifications on human health. It also presents the fundamental principles of liquid phase and solid phase microextraction methods, and gives a comprehensive account of the use of DESs for the determination of EDCs in various samples.

Dual sorbent coating based magnet-integrated fabric phase sorptive extraction as a front-end to gas chromatography-mass spectrometry for multi-class pesticide determination in water samples

Magnet-integrated fabric phase sorptive extraction (MI-FPSE) is a sample preparation technique that has proved to be a powerful tool for environmental analysis. The fabrication and application of magnet-integrated dual sorbent-based FPSE membrane prepared by combining two different sol-gel sorbent-coated disks of different polarities together with a magnetic bar inserted between the two membranes to allow the stirring, was examined as novel preparation technique that not required samples pretreatments. The dual sorbent-based sample preparation platforms (made up of poly(tetrahydrofuran) and Carbowax 20M) were used for the extraction of seven classes of pesticides from ambient surface water samples prior to their determination by gas chromatography-mass spectrometry. Initially, different single and dual sol-gel sorbent-based MI-FPSE membranes were evaluated in terms of their extraction efficiency. The MI-FPSE with dual sol-gel sorbents were found to be superior to the single-materials MI-FPSE devices in terms of extraction recovery. The main parameters affecting the MI-FPSE extraction protocol (e.g., adsorption time, sample volume, stirring rate, salt addition, eluent type, desorption time and elution volume) were investigated. The selected extraction protocol enabled detection limits in the range between 0.001 and 0.16 ng mL-1. Furthermore, good relative standard deviation values for the intra-day and inter-day repeatability studies were obtained and were lower than 5.9 and 9.9 %, respectively. The proposed method was successfully used for the multi-class analysis of environmental surface water samples.

Ternary solvent based homogeneous liquid-liquid microextraction for the preconcentration of organochlorine pesticides from water and apple juice samples

In the present study, the optimal experimental conditions were determined by optimizing the effect of extraction solvent types and volume, salt types and concentration, centrifugation speed and time using one variable at a time. Under optimal experimental conditions, calibration curves were constructed separately using water and apple juice samples as representative matrices, and good linearities were achieved over a wide concentration range of 0.2-1600 ng L-1 with a coefficient of determination (r2) ≥ 0.998. The limits of detection (LOD) and limits of quantification (LOQ), determined to be 3 and 10 times the signal-to-noise ratios (S/N), were between 0.07-3.9 and 0.2-12.0 ng L-1 for water samples and 2.6-10.0 and 8.0-30.0 ng L-1 for the apple juice sample respectively. The precisions study showed %RSD values of ≤6% for both matrices, indicating satisfactory precisions. The enrichment factors and recoveries of the proposed method ranged from 41.4-74.5 and 86-109% respectively. The proposed method could be used as a simple and environmentally friendly alternative for the analysis of OCPs from environmental and food matrices. This method potentially offers a more sustainable and effective approach to monitoring OCPs in environmental and food products. Its use in the analysis of apple juice samples is particularly novel and can provide valuable insights into pesticide contamination in fruit juices.

Sensing of organophosphorus pesticides by fluorescent complexes based on purine-hydrazone receptor and copper (II) and its application in living-cells imaging

In this study, we used purine hydrazone derivatives and coumarin aldehyde to synthesize a novel fluorescent sensor (EDTP) by Schiff base reaction, which exhibited significant selective fluorescence quenching of Cu²⁺, and a distinct change from brilliant yellow to red is present along with the solution color. The detection limit of EDTP for Cu²⁺ was 109.52 nM. Job's plot experiment, density flooding theory (DFT) and ¹H NMR titration experiments revealed the possible binding mechanism of EDTP to Cu²⁺, the probe EDTP could achieve highly detection of Cu²⁺ through forming a 1:1 complex. Additionally, this new fluorescent sensor EDTP-Cu²⁺ can be further applied in the rapid and selective detection of pesticide residues in solutions. When the EDTP-Cu²⁺ system was subsequently exposed to organophosphorus pesticides (glyphosate and glufosinate-ammonium), it was observed that the fluorescence was recovered and accompanied by a red to yellow color change. This may be attributed to the strong chelation of glyphosate and glufosinate-ammonium with Cu²⁺, leading to the dissociation of the EDTP-Cu²⁺ system and thus triggering the fluorescence recovery effect. The detection limits of the EDTP-Cu²⁺ system is 2.48 nM for glyphosate and 17.23 nM for glufosinate-ammonium, respectively. Finally, the developed sensor system has been successfully utilized image glyphosate and glufosinate-ammonium fluorescence in living cells. Purine fluorescence probes are a potential fluorescent probe for the detection of metal ions and pesticides due to their good characteristics. This study opens up a new way for the detection of fluorescent probes in pesticides.

Pesticides monitoring in biological fluids: Mapping the gaps in analytical strategies

Pesticides play a key-role in the development of the agrifood sector allowing controlling pest growth and, thus, improving the production rates. Pesticides chemical stability is responsible of their persistency in environmental matrices leading to bioaccumulation in animal tissues and hazardous several effects on living organisms. The studies regarding long-term effects of pesticides exposure and their toxicity are still limited to few studies focusing on over-exposed populations, but no extensive dataset is currently available. Pesticides biomonitoring relies mainly on chromatographic techniques coupled with mass spectrometry, whose large-scale application is often limited by feasibility constraints (costs, time, etc.). On the contrary, chemical sensors allow rapid, in-situ screening. Several sensors were designed for the detection of pesticides in environmental matrices, but their application in biological fluids needs to be further explored. Aiming at contributing to the implementation of pesticides biomonitoring methods, we mapped the main gaps between screening and chromatographic methods. Our overview focuses on the recent advances (2016-2021) in analytical methods for the determination of commercial pesticides in human biological fluids and provides guidelines for their application.

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.

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.

Current development of bioanalytical sample preparation techniques in pharmaceuticals

Sample preparation is considered as the bottleneck step in bioanalysis because each biological matrix has its own unique challenges and complexity. Competent sample preparation to extract the desired analytes and remove redundant components is a crucial step in each bioanalytical approach. The matrix effect is a key hurdle in bioanalytical sample preparation, which has gained extensive consideration. Novel sample preparation techniques have advantages over classical techniques in terms of accuracy, automation, ease of sample preparation, storage, and shipment and have become increasingly popular over the past decade. Our objective is to provide a broad outline of current developments in various bioanalytical sample preparation techniques in chromatographic and spectroscopic examinations. In addition, how these techniques have gained considerable attention over the past decade in bioanalytical research is mentioned with preferred examples. Modern trends in bioanalytical sample preparation techniques, including sorbent-based microextraction techniques, are primarily emphasized.

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Bioanalytical sampling techniques are described with suitable applications in pharmaceuticals.

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The pros and cons of each bioanalytical sampling techniques are described.

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Relevant biological matrices are outlined.

Layered filter paper-silver nanoparticle-ZIF-8 composite for efficient multi-mode enrichment and sensitive SERS detection of thiram

A SERS substrate FP/Ag/ZIF-8 composed of filter paper (FP), silver nanoparticles (AgNPs) and zeolitic imidazolate framework (ZIF-8) film arranged in a layered structure was developed for sensitive detection of pesticide thiram in various samples. Roles of these components in analyte adsorption and Raman signal enhancement were studied using a pesticide intermediate 4-Aminothiophenol (4-ATP) as the probe. The substrate showed high adsorption and optimized SERS response with thick metal organic framework (MOF) coating (125 nm), which is different from previous reported plasmonic particle-MOF composite substrate, where thinnest MOF coating produced the strongest SERS signal. Detection limit for 4-ATP improved 1000-fold on FP/Ag/ZIF-8 (3 pM) compared with that on FP/Ag (3 nM). Importantly, the FP/Ag/ZIF-8 with porous and flexible property can efficiently capture pesticide thiram in different real samples using soaking, filtration or swabbing operation. The subsequent SERS detection of thiram showed advantages of low detection limit (soaking, LOD: 0.04 nM in lake water), fast detection (filtration, within 1 min in peach juice) and suitable for curve surface analysis (swabbing, LOD: 0.1 ng/cm² on apple peel), respectively. The substrate also displayed good reproducibility, high stability and size-selective response for thiram detection. Such a layered plasmonic particle/MOF hybrid may hold great promise for toxicant analysis in environment and food.

Single-drop microextraction technique for the determination of antibiotics in environmental water

Growing concerns related to antibiotic residues in environmental water have encouraged the development of rapid, sensitive, and accurate analytical methods. Single-drop microextraction has been recognized as an efficient approach for the isolation and preconcentration of several analytes from a complex sample matrix. Thus, single-drop microextraction techniques are cost-effective and less harmful to the environment, subscribing to green analytical chemistry principles. Herein, an overview and the current advances in single-drop microextraction for the determination of antibiotics in environmental water are presented were included. In particular, two main approaches used to perform single-drop microextraction (direct immersion-single-drop microextraction and headspace-single-drop microextraction) are reviewed. Furthermore, the impressive analytical features and future perspectives of single-drop microextraction are discussed in this review. This article is protected by copyright. All rights reserved.

Facile and highly efficient three-phase single drop microextraction in-line coupled with capillary electrophoresis

A high-performance version of in-line, three-phase direct immersion-single drop microextraction (DI-SDME) coupled with capillary electrophoresis (CE) was demonstrated using a commercial CE instrument, and all the major and minor details were described to provide an easy-to-follow and user-friendly protocol. The excellent sample cleanup and enrichment power of this method was demonstrated with nonsteroidal anti-inflammatory drugs (NSAIDs) in human urine. The only preparation of urine samples was the addition of HCl to acidify the urine sample to pH 2. The acidic NSAIDs in the acidified urine sample were extracted into a basic acceptor drop covered with a thin organic layer attached to the inlet tip of a capillary immersed in the sample. A simple but powerful DI-SDME-CE method could be carried out automatically without any modification of the existing CE instrument. For improved performance, sample agitation and heating were employed by installing a microstirrer and a thermostating jacket in the sample tray. With 10 min of DI-SDME at 35°C with stirring, NSAIDs such as ketoprofen, ibuprofen, and naproxen in urine were enriched 340-970-fold with intraday and interday RSDs of 0.8-2.4% and 1.1-3.6%, respectively. The LODs obtained with in-line coupled CE/UV were 10-50 nM (2-10 µg/L). The performance of DI-SDME-CE/UV was also demonstrated by determining the naproxen level in human urine collected 24 h after taking a single oral dose of the drug. The spike recovery of naproxen from a single-point standard addition to the urine sample was 80%. Our high-performance three-phase DI-SDME-CE method is quite promising for the analysis of ionizable trace analytes in a complex sample matrix.

Binary Eluent Based Vortex-Assisted Matrix Solid-Phase Dispersion for the Extraction and Determination of Multicomponent from Musk by Gas Chromatography-Mass Spectrometry

A green, flexible, and effective strategy was proposed to quantify four target compounds (muscone, ethyl palmitate, ethyl oleate, and ethylparaben) from musk by binary eluent based vortex-assisted matrix solid-phase dispersion (MSPD) extraction coupled with GC/MS. Single-factor tests and orthogonal design were employed to optimize the MSPD parameters. In addition, the binary eluent system, methanol, and ethyl acetate 3 : 7 (v/v) were used to extract the target analytes. Finally, C ₁₈ was applied as the easily available dispersant and the sample powder was ground for 2 min. Thereafter, the mixture was rapidly extracted with the binary eluents under whirling for 3 min. Eventually, the analysis of the samples was completed within 12 min by GC/MS. All correlation coefficients (r) of four targets were more than 0.9991. The recoveries of all target compounds ranged from 92.8% to 101% while their RSDs were less than 6.94%. There was no significant matrix interference for the analysis. Thus, the combination of vortex-assisted MSPD with GC/MS was considered as a novel, rapid, and environmentally friendly quantitative approach for musk samples.

Current Applications of Magnetic Nanomaterials for Extraction of Mycotoxins, Pesticides, and Pharmaceuticals in Food Commodities

Environmental pollutants, such as mycotoxins, pesticides, and pharmaceuticals, are a group of contaminates that occur naturally, while others are produced from anthropogenic sources. With increased research on the adverse ecological and human health effects of these pollutants, there is an increasing need to regularly monitor their levels in food and the environment in order to ensure food safety and public health. The application of magnetic nanomaterials in the analyses of these pollutants could be promising and offers numerous advantages relative to conventional techniques. Due to their ability for the selective adsorption, and ease of separation as a result of magnetic susceptibility, surface modification, stability, cost-effectiveness, availability, and biodegradability, these unique magnetic nanomaterials exhibit great achievement in the improvement of the extraction of different analytes in food. On the other hand, conventional methods involve longer extraction procedures and utilize large quantities of environmentally unfriendly organic solvents. This review centers its attention on current applications of magnetic nanomaterials and their modifications in the extraction of pollutants in food commodities.

Review: Microextraction Technique Based New Trends in Food Analysis

Food chemistry is the study and classification of the quality and origin of foods. The identification of definite biomarkers and the determination of residue contaminants such as toxins, pesticides, metals, human and veterinary drugs, which are a very common source of food-borne diseases. The food analysis is continuously demanding the improvement of more robust, sensitive, highly efficient, and economically beneficial analytical approaches to promise the traceability, safety, and quality of foods in the acquiescence with the consumers and legislation demands. The traditional methods have been used at the starting of the 20th century based on wet chemical methods. Now it existing the powerful analytical techniques used in food analysis and safety. This development has led to substantial enhancements in the analytical accuracy, precision, sensitivity, selectivity, thereby mounting the applied range of food applications. In the present decade, microextraction (micro-scale extraction) pays more attention due to its futures such as low consumption of solvent and sample, throughput analysis easy to operate, greener, robotics, and miniaturization, different adsorbents have been used in the microextraction process with unique nature recognized with wide range applications.

Direct immersion single-drop microextraction of semi-volatile organic compounds in environmental samples: A review

Single-drop microextraction (SDME) techniques are efficient approaches to pretreatment of aqueous samples. The main advantage of SDME lies in the miniaturization of the solvent extraction process, minimizing the hazards associated with the use of toxic organic solvents. Thus, SDME techniques are cost-effective, and represent less harm to the environment, subscribing to green analytical chemistry principles. In practice, two main approaches can be used to perform SDME - direct immersion (DI)-SDME and headspace (HS)-SDME. Even though the DI-SDME has been shown to be quite effective for extraction and enrichment of various organic compounds, applications of DI-SDME are normally more suitable for moderately polar and non-polar semi-volatile organic compounds (SVOCs) using organic solvents which are immiscible with water. In this review, we present a historical overview and current advances in DI-SDME, including the common analytical tools which are usually coupled with DI-SDME. The review also focuses on applications concerning SVOCs in environmental samples. Currents trends in DI-SDME and possible future direction of the procedure are discussed.

In Situ Recyclable Surface-Enhanced Raman Scattering-Based Detection of Multicomponent Pesticide Residues on Fruits and Vegetables by the Flower-like MoS2@Ag Hybrid Substrate

Pesticides, extensively used in agriculture production, have received enormous attention because of their potential threats to the environment and human health. Hence, in this study, a kind of highly sensitive and stable hybrid surface-enhanced Raman scattering (SERS)-active substrates constructed with flower-like two-dimensional molybdenum sulfide and Ag (MoS₂@Ag) has been developed, and then the above substrate was sequentially utilized in the recyclable detection of pesticide residues on several kinds of fruits and vegetables. In the first place, the excellent photocatalytic performance of the MoS₂@Ag hybrid substrate was demonstrated, which was attributed to the inhibition of electron-hole combination after the formation of Schottky barrier between the Ag NPs and MoS₂ matrix. Thereafter, two calibration curves with ultra-low limits of detection (LOD) as 6.4 × 10^-7 and 9.8 × 10^-7 mg/mL were established for the standard solutions of thiram (tetramethylthiuram disulfide, TMTD) and methyl parathion (MP), and then the recyclable assay of their single and mixed residues on eggplant, Chinese cabbage, grape, and strawberry was successfully realized. It is interesting to note that the detection recoveries from 95.5 to 63.1% for TMTD and 92.3 to 62.6% for MP are greatly dependent on the size and surface roughness of these foods. In a word, the MoS₂@Ag composite matrix shows attractive SERS and photocatalysis performance, and it is expected to have the potential application on food safety monitoring.

Determination of homocysteine thiolactone in human urine by capillary zone electrophoresis and single drop microextraction

A simple, fast, sensitive and reproducible capillary zone electrophoresis (CZE) method with single drop microextraction (SDME) for determination of homocysteine thiolactone (HTL) in human urine has been developed and validated. The method is characterized by good precision, high accuracy, short analysis time and low consumption of reagents. The procedure consists only of few steps: urine sample centrifugation, dilution with phosphate buffer and methanol, chloroform addition onto the top of donor phase, on-line SDME in CE system, sample separation by CZE and ultraviolet detection of HTL at 240 nm. The background electrolyte was 0.1 M pH 4.75 phosphate buffer. Effective separation was achieved within 6.04 min under the separation voltage of 24 kV (~110 μA). The LOQ and LOD for HTL were 50 and 25 nM urine, respectively. The calibration curve in urine showed linearity in the range of 50-200 nM, with R² 0.9995. The intra- and inter-day precision and recovery were 4.0-14.5% (average 8.7% and 9.3%) and 92.7-115.5% (average 103.6% and 104.8%), respectively. The procedure was successfully applied to analysis of urine samples.

Magnetic solid phase extraction using Fe3O4@β-cyclodextrin–lipid bilayers as adsorbents followed by GC-QTOF-MS for the analysis of nine pesticides

A rapid method for the analysis of trace organochlorine pesticides in a complex matrix.

Matrix solid-phase dispersion based on magnetic ionic liquids: An alternative sample preparation approach for the extraction of pesticides from vegetables

In this study, we propose, for the first time, the direct use of a magnetic ionic liquid (MIL) in a matrix solid-phase extraction procedure. Because of the magnetic properties, the MIL can be harvested directly after the extraction step, using a magnet, while its hydrophobic nature makes feasible the extraction of analytes. Raw vegetables of high water content can be analyzed without any pretreatment. The viscous nature of the selected MIL assists in blending with the matrix, while its hydrophobicity facilitates easier separation and retrieval. Additionally, no solid dispersing materials or co-sorbents are needed. A simple, low-cost analytical method for the determination of multi-class pesticides residues in raw vegetables was developed, with satisfactory recoveries.