Cyclodextrin-based dispersive liquid-liquid microextraction for the determination of fungicides in water, juice, and vinegar samples via HPLC

Quick synthesis of CoFe-PBA@GO with electrochemical method as a novel, sensitive, and degradable nanocomposite applied in nanofibers for triazole extraction before HPLC-UV analysis

Today, the wide use of triazole fungicides due to environmental damage and its side effects has raised global concern. Hence, in this research, poly-vinyl alcohol/polyacrylic-acid/CoFe-PBA@GO electrospun nanofiber was synthesized and applied as effective, degradable, and novel adsorbent at pipette-tip microextraction (PT-μSPE) method for the rapid and concurrent extraction of five of triazole fungicides in fruit and vegetable samples prior to quantitative analysis by high-performance liquid chromatography-ultraviolet. The incorporation of CoFe-PBA@GO with superporous structure and abundant functional groups in a polymer medium improves the extraction efficiency of nanofibers due to hydrogen bonding and π-π interactions formed between analytes and synthesized nano-adsorbent. Various important elements that affect the extraction yield of the target analytes were optimized utilizing a time-variable approach. Under the optimum conditions, dynamic range was attained in the range of 0.3-900.0 ng/mL with correlation coefficients ≥ 0.999. The identification limit of the PT-μSPE-HPLC-UV method ranged from 0.1 to 0.3 ng/mL.

High-throughput semi-automated emulsive liquid-liquid microextraction for detecting SDHI fungicides in water, juice, and alcoholic beverage samples via UHPLC-MS/MS

Herein, a High-Throughput Semi-automated Emulsive Liquid-Liquid Microextraction (HTSA-ELLME) method was developed to detect Succinate Dehydrogenase Inhibitor (SDHI) fungicides in food samples via UHPLC-MS/MS. The Oil-in-Water (O/W) emulsion comprising a hydrophobic extractant and water was dilutable with the aqueous sample solution. Upon injecting the primary emulsion into the sample solution, a secondary O/W emulsion was formed, allowing SDHI fungicides to be extracted. Subsequently, a NaCl-saturated solution was injected in the secondary O/W emulsion as a demulsifier to rapidly separate the extractant, eliminating the need for centrifugation. A 12-channel electronic micropipette was used to achieve a high-throughput semi-automation of the novel sample pretreatment. The linear range was 0.003-0.3 μg L-1 with R2 > 0.998. The limit of detection was 0.001 μg L-1. The HTSA-ELLME method successfully detected SDHI fungicides in water, juice, and alcoholic beverage samples, with recoveries and relative standard deviations of 82.6-106.9% and 0.8-5.8%, respectively. Unlike previously reported liquid-liquid microextraction approaches, the HTSA-ELLME method is the first to be both high-throughput and semi-automated and may aid in designing pesticide pretreatment processes in food samples.

Supramolecular deep eutectic solvent: a powerful tool for pre-concentration of trace metals in edible oil

The utilization of supramolecular deep eutectic solvent eddy-assisted liquid-liquid microextraction utilizing 2-hydroxypropyl β-cyclodextrin (SUPRADES) has been identified as a successful method for pre-enriching Cu, Zn, and Mn in vegetable oil samples. Determination of each element was conducted by inductively coupled plasma optical emission spectrometry (ICP-OES) after digestion of metal-enriched phases. Various parameters were examined, including the composition of SUPRADES species [2HP-β-CD: DL-lactic acid], a cyclodextrin mass ratio of 20 wt%, a water bath temperature of 75 °C, an extractor volume of 800 μL, a dispersant volume of 50 μL, and an eddy current time of 5 min. Optimal conditions resulted in extraction rates of 99.6% for Cu, 105.2% for Zn, and 101.5% for Mn. The method exhibits a broad linear range spanning from 10 to 20,000 μg L-1, with determination coefficients exceeding 0.99 for all analytes. Enrichment coefficients of 24, 21, and 35 were observed. Limits of detection ranged from 0.89 to 1.30 μg L-1, while limits of quantification ranged from 3.23 to 4.29 μg L-1. The unique structural characteristics of the method enable the successful determination of trace elements in a variety of edible vegetable oils.

Determination of chiral prothioconazole and its chiral metabolite in water, juice, tea, and vinegar using emulsive liquid-liquid microextraction combined with ultra-high performance liquid chromatography

Emulsive liquid-liquid microextraction (ELLME), a simple, rapid, and environmentally friendly technique, was established to identify chiral prothioconazole and its chiral metabolite in water, juice, tea, and vinegar using ultra-high-performance liquid chromatography (UPLC). Environmentally friendly extractant was mixed with pure water to prepare a high-concentration emulsion, which was added to samples to complete the emulsification and extraction in 1 s. Afterward, an electrolyte solution was added to complete the demulsification without centrifugation. ELLME did not use dispersants compared to the familiar dispersive liquid-liquid microextraction (DLLME), thus reducing the use of toxic solvents and avoiding the effect of dispersants on the partition coefficient. The linear range was from 0.01 to 1 mg/L. The limit of detection was 0.003 mg/L. The extraction recoveries ranged from 82.4 % to 101.6 %, with relative standard deviations of 0.7-5.2 %. The ELLME method developed has the potential to serve as an alternative to DLLME.

Synthesis and evaluation of a chitosan nanomaterial as efficient sorbent for determination of fungicide residues in waters and wine by liquid chromatography high resolution mass spectrometry

In the present study a novel, cost-effective, environmentally friendly, and efficient analytical method was developed to analyze fungicide residues in water and wine. The method relies on the application of a newly developed sorbent nanomaterial named Nano-Cs-NAT, synthesized by modifying chitosan, a naturally occurring, low-cost polysaccharide, through grafting with two acrylic monomers and a cross-linker. Nano-Cs-NAT was introduced as analytical sorbent for Dispersive Micro Solid Phase Extraction (D-μ-SPE) before Liquid Chromatography-Orbitrap High-Resolution Mass Spectrometry (LC-Orbitrap HRMS) analysis of twelve fungicides commonly used in viticulture (among the others, triazoles, strobilurines and N-substituted imidazoles). Characterization of the sorbent was conducted, confirming the successful acrylation of chitosan. A multivariate approach was employed to optimize D-μ-SPE extraction parameters. The material was found to be highly effective in simultaneously purifying and concentrating the target analytes, enhancing overall analytical efficiency and sensitivity. The Nano-Cs-NAT-D-μ-SPE-LC-Orbitrap-HRMS method was thoroughly validated, exhibiting good recoveries (72-104%), reproducibility (average RSD ≤ 6%) and repeatability (average RSD ≤ 7%). It also achieved low limits of detection (LOD) in river water (average LOD of 0.04 μg L-1) and wine (average LOD of 0.72 μg kg-1), highlighting its potential for routine fungicide residue analysis. This developed method addresses environmental and food safety concerns by providing an efficient solution for detecting fungicide residues in waters and wine.

Magnetic deep eutectic solvent-based dispersive liquid-liquid microextraction for determination of strobilurin fungicides in water, juice, and vinegar by high-performance liquid chromatography

In this study, a magnetic deep eutectic solvent coupled with dispersive liquid-liquid microextraction using high-performance liquid chromatography (MDES-DLLME-HPLC) was developed to detect strobilurin fungicides. The green hydrophobic MDES synthesized by methyltrioctylammonium chloride, ferric chloride, and heptanoic acid was used as an extraction solvent, which was dispersed by vortex and separated by an external magnetic field. The use of toxic solvents was avoided, and the separation time was reduced. The best experimental results were obtained through single factor and response surface optimization. The method had a good linear relationship with R² > 0.996. The limit of detection (LOD) ranged from 0.001 to 0.002 mg L^-1. The extraction recoveries were 81.9-108.9%. The proposed method was rapid and green, and it has been successfully applied to detection of strobilurin fungicides in water, juice, and vinegar.

Combination of switchable hydrophilic solvent liquid-liquid microextraction with QuEChERS for trace determination of triazole fungicide pesticides by GC-MS

This work first proposed a novel green and efficient method based on Quick, Easy, Cheap, Efficient, Rugged, and Safe pretreatment (QuEChERS) combined with switchable hydrophilic solvent homogeneous liquid-liquid microextraction (SHS-HLLME) for trace determination of triazole fungicides (TFs) in agricultural products such as vegetables and fruits by gas chromatography-mass spectrometry (GC-MS). N,N-Dimethyl benzylamine was used for the synthesis of SHS. Box-Behnken design was applied for the optimization of extraction conditions and a mathematical model was obtained. Ultimately, 0.50 mL SHS, 1.0 mL 10 mol L^-1 sodium hydroxide, and 45 s ultrasonic time were determined as optimal conditions for the SHS-HLLME method. The limit of detection and limit of quantification determined using the optimal method (SHS-HLLME/GC-MS) were 0.13-0.27 ng mL^-1 and 0.43-0.90 ng mL^-1, respectively. In addition, the SHS-HLLME method under optimal conditions was combined with the traditional QuEChERS method to realize the advancement of the SHS-HLLME method from simple to complex matrix analysis, and the QuEChERS-SHS-HLLME method was successfully applied to the analysis of TFs in cucumbers, tomatoes, watermelon and grapes in agricultural products. Matrix-matched calibration standards were used to improve the accuracy of TFs in spiked cucumber samples to obtain recovery results close to 100%. It was shown that the new method is green and rapid, enabling fast and inexpensive sample pretreatment with up to 100-fold enrichment factor and low detection limit compared with the original QuEChERS method.

Efficient analyses of triazole fungicides in water, honey and soy milk samples by popping candy-generated CO2 and sugaring-out-assisted supramolecular solvent-based microextraction prior to HPLC determinations

An enrichment method, namely popping candy-generated CO₂ and sugaring-out-assisted supramolecular solvent-based microextraction (PGS-SUPRA), was investigated for the determination of triazole fungicide residues in water, honey and soy milk samples. The extraction process was carried out by adding popping candies into a centrifuge tube. Consequently, rapid dispersion and mass transfer of extractants can be achieved without using dispersants and auxiliary devices, and therefore, the extraction efficiency increased. The extraction parameters affecting the efficiency of the developed method were investigated. The presented method was then analysed by high-performance liquid chromatography. Under the selected condition, the wide linearity of triazole fungicides after preconcentration by the proposed microextraction method ranged from 30 to 1000 μg L^-1 for triadimefon and from 90 to 1000 μg L^-1 for myclobutanil, tebuconazole and hexaconazole, with a coefficient for determination (R ²) greater than 0.992. The limits of detection (LODs) and limits of quantitation (LOQs) were in the range of 10-30 μg L^-1 and 30-90 μg L^-1, respectively. The precisions were assessed from the relative standard deviations (RSDs) of the retention time and peak area obtained from intra- (n = 3) and inter-day (n = 3 × 5) experiments, and were greater than 1.66% and 13.52%, respectively. Moreover, the proposed method provided high enhancement factors (EnFs) ranging from 14 to 51 folds. This technique has been prosperously applied for the extraction of fungicide residues in water, honey and soy milk samples with a recovery within the range of 60-114%. Overall, the developed method was found to be advantageous as compared with other sample preparation methods.

Direct solidification of switchable-hydrophilicity salicylic acid: A design for the on-site dispersive liquid-liquid microextraction of benzoylurea insecticides in water and honey samples

This study describes the development of a fully manual method for on-site dispersive liquid-liquid microextraction based on the direct solidification of switchable-hydrophilicity salicylic acid (on-site DLLME-DSSA) coupled with high-performance liquid chromatography with an ultraviolet detector (HPLC-UVD) and its utilization for the detection of benzoylurea insecticides (BUs) in water and honey samples. Salicylic acid (SA), a switchable hydrophilic aromatic acid, was used as an extraction solvent. It can be converted into the hydrophobic/hydrophilic forms in pH-changeable solutions, facilitating facile and effective dispersion and phase separation. Moreover, the melting point of SA (significantly higher than room temperature) enables its direct solidification without an ice-water bath, facilitating its collection by filtration. The dispersion, separation, and collection of the extraction solvent were carried out entirely in a plastic syringe without requiring special apparatus or additional energy. Univariate and response surface analyses were used to optimize various parameters of the on-site DLLME-DSSA method. Under optimal conditions, the limits of determination (LODs) were 1.50 µg L^-1 and 0.03-0.09 mg kg^-1 in water and honey, respectively. The relative standard deviations (RSDs) for inter-day (n = 5) and intra-day (n = 5) precision were ≤8.4%, whereas the extraction recoveries and enrichment factors for the BUs ranged from 67.0 to 97.1% and 29 to 34, respectively. Furthermore, the proposed method was used for the on-site extraction and laboratory detection of BUs from real water and honey samples. Theoretical analyses indicated non-covalent interactions (such as hydrogen bonds, electrostatic interactions, van der Waals forces, and π-π interactions) to be the main driving force for extraction. This study introduces a switchable hydrophilic aromatic acid capable of direct solidification into on-site DLLME for the first time, opening new frontiers in the development of on-site sample pretreatment methods.

Cyclodextrin Inclusion Complexes and Their Application in Food Safety Analysis: Recent Developments and Future Prospects

Food safety issues are a major threat to public health and have attracted much attention. Therefore, exploring accurate, efficient, sensitive, and economical detection methods is necessary to ensure consumers' health. In this regard, cyclodextrins (CDs) are promising candidates because they are nontoxic and noncaloric. The main body of CDs is a ring structure with hydrophobic cavity and hydrophilic exterior wall. Due to the above characteristics, CDs can encapsulate small guest molecules into their cavities, enhance their stability, avoid agglomeration and oxidation, and, at the same time, interact through hydrogen bonding and electrostatic interactions. Additionally, they can selectively capture the target molecules to be detected and improve the sensitivity of food detection. This review highlights recent advances in CD inclusion technology in food safety analysis, covering various applications from small molecule and heavy metal sensing to amino acid and microbial sensing. Finally, challenges and prospects for CDs and their derivatives are presented. The current review can provide a reference and guidance for current research on CDs in the food industry and may inspire breakthroughs in this field.

Simultaneous Preconcentration of Triazole Fungicide Residues Using In-Situ Coacervative Extraction Based on a Double-Solvent Supramolecular System Prior to High Performance Liquid Chromatographic Analysis

An in situ coacervative extraction (IS-CAE) based on a double-solvent supramolecular system coupled to liquid–liquid microextraction is investigated for extraction and enrichment of triazole fungicides. The formation of a double-solvent supramolecular system was generated by in situ formation and used as an extraction solvent for the coacervative extraction method. No disperser solvent was required. This new double-solvent supramolecular system has a higher extraction ability than any of its components alone. The different factors that could affect the extraction capability were studied and optimized, including the type of double extractant and its volume, salt addition, vortex time, and centrifugation time. Under optimum extraction conditions, this method provides high enrichment factors (EFs) of 73–318 with low limits of detection (LODs) of 0.3–1 μg L⁻¹ and limits of quantitation (LOQs) of 1–3 μg L⁻¹. In addition, the proposed method was prosperously applied for the determination of triazole fungicides in water, fruit juice, and soy milk samples.

Construction of a magnetic solid-phase extraction method for the analysis of azole pesticides residue in medicinal plants

In this work, a sensitive and cost-effective method for the quantitative analysis of azole pesticides residues in six medicinal plants was established based on magnetic cyclodextrin crosslinked with tetrafluoroterephthalonitrile (Fe₃O₄@TFN-CDPs) coupled with high-performance liquid chromatography (HPLC). Through characterization analysis, the outer shell of Fe₃O₄@TFN-CDPs has observed coating with a network of the polymer and forming a core-shell structure. Under the optimum conditions, the limits of detection (LODs) and limits of qualification (LOQs) of target pesticides were ranged from 0.011 to 0.106 µg Kg^-1 and from 0.036 to 0.354 µg Kg^-1, respectively. Finally, the achieved recoveries of pesticides in six medicinal samples fluctuated from 60.1% to 102.3%. Altogether, this method based on Fe₃O₄@TFN-CDPs composites provided a new idea for the analysis of trace pesticides in complicated matrices.

Preparation of metal-organic framework @molecularly imprinted polymers for extracting strobilurin fungicides from agricultural products

The core-shell metal-organic framework coated with molecularly imprinted polymers (ZIF-8@MIPs) were successfully synthesized by surface imprinting technique, and applied as adsorbents for solid-phase extraction of strobilurin fungicides. The obtained hybrid complex was characterized in detail, and their adsorbing and recognition performance were evaluated. The results showed that ZIF-8@MIPs presented typically core-shell structure with MIP shell (about 20 nm), and exhibited larger adsorption capacity (102.5 mg g^-1) and fast adsorption ability (only 5 min). Under the optimized conditions, a sensitive, efficient and reliable method for determining six strobilurin fungicides in different agricultural products based on ZIF-8@MIPs coupling with high performance liquid chromatography-tandem mass spectrometry was established. This method showed good linearity with correlation coefficients higher than 0.9990. With spiked at three different concentration levels in agricultural products (apple, pear, banana, Chinese cabbage, cabbage, cucumber), the good recoveries (83.5-129.0%) with relative standard deviations from 0.5 to 10.2% were obtained. The limit of detections and the limit of quantifications were 0.01-1.12 ng g^-1 and 0.03-3.73 ng g^-1, respectively. Those results demonstrated good potential application of ZIF-8@MIPs for enriching and separating trace strobilurin fungicides in agricultural samples.

Facile and Selective Determination of Total Phthalic Acid Esters Level in Soft Drinks by Molecular Fluorescence Based on Petroleum Ether Microextraction and Selective Derivation by H2SO4

Determining the level of phthalic acid esters (PAEs) in packaged carbonated beverages is a current need to ensure food safety. High-selectivity and -accuracy identification of individual PAEs can be achieved by chromatographic and mass spectrometric (MS) techniques. However, these methods are slow; involve complicated, expensive instruments in professional laboratories; and consume a large amount of organic solvents. As such, a food analysis method is needed to conveniently and rapidly evaluate multiple contaminants on site. In this study, with the assistance of ultrasound, we quickly determined the total PAEs in soft drinks using 1.5 mL of petroleum ether in one step. Then, we determined the characteristic molecular fluorescence spectrum of all PAEs in samples (excitation (Ex)/emission (Em) at 218/351 nm) using selectively concentrated sulfuric acid derivatization. The relative standard deviations of the fluorescent intensities of mixed solutions with five different PAEs were lower than 7.1% at three concentration levels. The limit of detection of the proposed method is 0.10 μmol L−1, which matches that of some of the chromatographic methods, but the proposed method uses less organic solvent and cheaper instruments. These microextraction devices and the fluorescence spectrometer are portable and provide an instant result, which shows promise for the evaluation of the total level of PAEs in beverages on site. The proposed method successfully detected the total level of PAEs in 38 kinds of soft drink samples from local supermarkets, indicating its potential for applications in the packaged beverage industry.

Rapid analysis of triazine herbicides in fruit juices using evaporation-assisted dispersive liquid-liquid microextraction with solidification of floating organic droplets and HPLC-DAD

A rapid and convenient analytical procedure (evaporation-assisted dispersive liquid-liquid microextraction with solidification of floating organic droplets) is advanced for determining the concentrations of triazine herbicide residues (e.g. simazine and atrazine) in fruit juices via HPLC-DAD. The technique involves adding 1-dodecanol (low density) and dichloromethane (high density) to the test solution to act as the extraction and volatile solvents, respectively. Calcium oxide is added to generate heat to accelerate the evaporation of dichloromethane, whereupon the 1-dodecanol quickly disperses into small droplets to complete the microextraction process. Thus, there is no need to use a dispersive solvent and heating equipment is also not required. The floating 1-dodecanol is subsequently frozen using an ice bath to facilitate its separation from the sample. Under optimal conditions (250 μL of 1-dodecanol (extraction solvent), 150 μL of CH₂Cl₂ (volatile solvent), 1250 mg of CaO, and an extraction time of 60 s) the detection procedure is linear over the range 0.05-5 μg mL^-1 (with R > 0.99). The limits of detection (LOD) and quantification (LOQ) were determined to be 0.0022-0.0034 μg mL^-1 and 0.0073-0.0113 μg mL^-1, respectively. The recovery of simazine and atrazine in three fruit juices ranged between 78.5% and 96.4% with a relative standard deviation <8.2%. Therefore, the proposed approach can be effectively adopted to analyze the triazine herbicide content in fruit juices. The method has been proved to be simple, reliable, and remarkably efficient.

Ultrasound-assisted switchable hydrophilic solvent-based homogeneous liquid-liquid microextraction for the determination of triazole fungicides in environmental water by GC-MS

A new method was developed for the determination of three triazole fungicides in environmental water samples by gas chromatography-mass spectrometry (GC-MS) based on ultrasonic assisted switchable hydrophilic solvent homogeneous liquid-liquid microextraction. As a switchable hydrophilic solvent, N,N-dimethylcyclohexylamine (DMCHA) does not require a dispersant or centrifugation. Ultrasound assistance is helpful to speed up the extraction of target compounds and can reduce the pretreatment time. The entire pretreatment process of this method only takes 5 minutes. Using the Box-Behnken design as the means of optimization, optimal extraction conditions were obtained through a mathematical model. Good linearity was obtained in the range of 5-500 μg L^-1, and the correlation coefficient of target compounds was greater than 0.999. The matrix spiked recoveries were between 81.3% and 111.1% and the detection limit was between 0.46 and 0.99 μg L^-1. Intraday relative standard deviation (n = 3) was 13.0-13.9% at 100 μg L^-1. Finally, it was concluded that the method is a rapid, efficient and simple method for the analysis of triazole fungicides in water.