Selective solid-phase extraction based on molecularly imprinted technology for the simultaneous determination of 20 triazole pesticides in cucumber samples using high-performance liquid chromatography-tandem mass spectrometry

Trace-Level Determination of Triazole Fungicides Using Effervescence-Assisted Liquid-Liquid Microextraction Based on Ternary Deep Eutectic Solvent Prior to High-Performance Liquid Chromatography

A simple and sensitive preconcentration method, namely, effervescence-assisted liquid-liquid microextraction based on the ternary deep eutectic solvent method, was developed for enrichment of triazole fungicide residues prior to their determination by high-performance liquid chromatography coupled with UV detection. In this method, a ternary deep eutectic solvent (as extractant) was prepared by combination of octanoic acid, decanoic acid, and dodecanoic acid. The solution was well dispersed with sodium bicarbonate (as effervescence powder) without using auxiliary devices. In order to obtain relatively high extraction efficiency, analytical parameters were investigated and optimized. Under optimum conditions, the proposed method showed good linearity within the range of 1-1000 μg L^-1 with a coefficient for determination (R²) greater than 0.997. The low limits of detection (LODs) were in the range of 0.3-1.0 μg L^-1. The precisions were assessed from the relative standard deviations (RSDs) of retention time and peak area obtained from intra- (n = 3) and inter-day (n = 5 × 5) experiments, which were greater than 1.21 and 4.79%, respectively. Moreover, the proposed method provided high enrichment factors ranging from 112 to 142 folds. A matrix-match calibration method was used for analysis of real samples. Finally, the developed method was successfully applied for determination of the triazole fungicide in environmental water (near agricultural area), honey, and bean samples, and it represents a promising alternative method for analysis of triazoles. The recoveries of the studied triazoles were obtained in the range of 82-106% with an RSD less than 4.89.

Recent advances in emerging application of functional materials in sample pretreatment methods for liquid chromatography-mass spectrometry analysis of plant growth regulators: A mini-review

Plant growth regulators (PGRs) are a class of small molecular compounds, which can remarkably affect the physiological process of plants. The complex plant matrix along with a wide polarity range and unstable chemical properties of PGRs hinder their trace analysis. In order to obtain a reliable and accurate result, a sample pretreatment process must be carried out, including eliminating the interference of the matrix effect and pre-concentrating the analytes. In recent years, the research of functional materials in sample pretreatment has experienced rapid growth. This review comprehensively overviews recent development in functional materials covering one-dimensional materials, two-dimensional materials, and three-dimensional materials applied in the pretreatment of PGRs before liquid chromatography-mass spectrometry (LC-MS) analysis. Besides, the advantages and limitations of the above functionalized enrichment materials are discussed, and their future trends have been prospected. The work could be helpful to bring new insights for researchers engaged in functional materials in sample pretreatment of PGRs based on LC-MS.

In Silico Investigation of Selected Pesticides and Their Determination in Agricultural Products Using QuEChERS Methodology and HPLC-DAD

In this study, we considered some pesticides as active substances within formulations for the protection of plant-based food in the Republic of Serbia in silico, because these pesticides have not often been investigated in this way previously, and in an analytical way, because there are not very many available fast, cheap, and easy methods for their determination in real agricultural samples. Seven pesticides were detected in selected agricultural products (tomatoes, cucumbers, peppers, and grapes) using the QuEChERS methodology and HPLC-DAD. Standard curves for the investigated pesticides (chlorantraniliprole, methomyl, metalaxyl, thiacloprid, acetamiprid, emamectin benzoate, and cymoxanil) show good linearity, with R² values from 0.9785 to 0.9996. The HPLC-DAD method is fast, and these pesticides can be determined in real spiked samples in less than 15 min. We further characterized the pesticides we found in food based on physicochemical properties and molecular descriptors to predict the absorption, distribution, metabolism, elimination, and toxicity (ADMET) of the compounds. We summarized the data supporting their effects on humans using various computational tools to determine their potential adverse effects. The results of our prediction study show that all of the selected pesticides considered in this study have good oral bioavailability, and those with high toxicity, therefore, could be harmful to human health. Chlorantraniliprole was shown in a molecular docking study as a good starting point for a new Alzheimer's disease drug candidate.

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.

Advances on Hormones in Cosmetics: Illegal Addition Status, Sample Preparation, and Detection Technology

Owing to the rapid development of the cosmetic industry, cosmetic safety has become the focus of consumers' attention. However, in order to achieve the desired effects in the short term, the illegal addition of hormones in cosmetics has emerged frequently, which could induce skin problems and even skin cancer after long-term use. Therefore, it is of great significance to master the illegal addition in cosmetics and effectively detect the hormones that may exist in cosmetics. In this review, we analyze the illegally added hormone types, detection values, and cosmetic types, as well as discuss the hormone risks in cosmetics for human beings, according to the data in unqualified cosmetics in China from 2017 to 2022. Results showed that although the frequency of adding hormones in cosmetics has declined, hormones are still the main prohibited substances in illegal cosmetics, especially facial masks. Because of the complex composition and the low concentration of hormones in cosmetics, it is necessary to combine efficient sample preparation technology with instrumental analysis. In order to give the readers a comprehensive overview of hormone analytical technologies in cosmetics, we summarize the advanced sample preparation techniques and commonly used detection techniques of hormones in cosmetics in the last decade (2012-2022). We found that ultrasound-assisted extraction, solid phase extraction, and microextraction coupled with chromatographic analysis are still the most widely used analytical technologies for hormones in cosmetics. Through the investigation of market status, the summary of sample pretreatment and detection technologies, as well as the discussion of their development trends in the future, our purpose is to provide a reference for the supervision of illegal hormone residues in cosmetics.

Covalent organic framework in situ grown on Fe3O4 hollow microspheres for stir bar sorptive-dispersive microextraction of triazole pesticides

Based on covalent organic framework (COF) 1,3,5-tris-(4-formylphenyl)benzene-benzidine (TFPB-BD) in situ grown on Fe₃O₄ hollow microspheres and combined with gas chromatography-flame thermionic detector, a rapid and simple stir bar sorptive-dispersive microextraction method was developed for the determination of five triazole pesticides (paclobutrazol, hexaconazole, flusilazole, propiconazole, and tebuconazole). The synthesized TFPB-BD/Fe₃O₄ microspheres were characterized by transmission electron microscope, vibrating sample magnetometer, and thermogravimetric analysis, which showed that the material has strong magnetism and higher load capacity of COF. Under optimal conditions, the extraction equilibrium could be achieved within 9 min with detection limits of 0.17-1.48 μg L^-1 (S/N = 3) and a linear range of 5-1000 μg L^-1. The developed method was applied to the determination of trace triazole pesticides in apples, pears, and cabbages with recoveries from 81 to 117%.

Estimation of residue levels and dietary risk assessment of cyproconazole and azoxystrobin in cucumber after field application in China

Residue field trials in cucumber were conducted for the safe use of a commercial formulation of cyproconazole·azoxystrobin 28% suspension concentrate (SC 294 g a.i. ha^-1, three applications at a 7-day interval) in the year 2018, in China. To determine the residues of cyproconazole and azoxystrobin in cucumber, a quick, easy, cheap, effective, rugged, and safe (QuEChERS) method was developed using high-performance liquid chromatography coupled with tandem mass spectrometry. This validated method was applied to analyze cucumber samples collected from 12 specified regions. At the 3-day interval to harvest, the highest residue (HR) of azoxystrobin was 0.150 mg kg^-1, which was lower than the maximum residue limit (MRL; 0.5 mg kg^-1) permitted in China, and the HR of cyproconazole was 0.084 mg kg^-1, for which no MRL value has been set in China. The chronic risk quotient values of cyproconazole and azoxystrobin for Chinese adults at a 3-day interval to harvest were 2.56% and 13.72%, respectively. The acute risk quotient values of cyproconazole in cucumber were specified as 5.52% for children (1-6 years old) and 2.83% for the adults (> 18 years old) in China. These results indicate that cyproconazole·azoxystrobin 28% SC sprayed on cucumber at the pre-harvest interval of 3 days has no significant potential risk for Chinese consumers.

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.

[Advances in application of molecularly imprinted polymers to the detection of polar pesticide residues]

Polar pesticides can be primarily classified as fungicides, herbicides, and insecticides; their rich variety and low cost have led to their extensive utilization in agriculture. However, the overuse of polar pesticides can lead to environmental contamination, such as water or soil pollution, which can also increase the risk of pesticide exposure among human life directly, or indirectly through contact with animal and plant-derived food. There are considerable differences in the physical and chemical properties of polar pesticides, as well as their trace amounts in complex food and environmental samples, posing immense challenges to their accurate detection. As a kind of artificially prepared selective adsorbent, molecularly imprinted polymers (MIPs) possess specific recognition sites complementary to template molecules in terms of the spatial structure, size, and chemical functional groups. With many advantages such as easy preparation, low cost, as well as good chemical and mechanical stability, MIPs have been widely applied in sample pretreatment and the analysis of polar pesticide residues. MIPs are typically used as adsorption materials in solid phase extraction (SPE) methods, including magnetic solid phase extraction (MSPE), dispersed solid phase extraction (DSPE), and stir bar sorptive extraction (SBSE). To rapidly detect polar pesticide residues with high sensitivity, MIPs are also used in the preparation of fluorescent sensors and electrochemical sensors. Furthermore, MIPs can be employed as the substrate in surface-enhanced Raman spectroscopy and as the substrate for the ion source in mass spectrometry for polar pesticide residue analysis. Thus far, various molecularly imprinted materials have been reported for the efficient separation and analysis of polar pesticide residues in various complex matrices. However, there is no review that summarizes the recent advances in MIPs for the determination of polar pesticides. This review introduces imprinting strategies and polymerization methods for MIPs, and briefly summarizes some new molecular imprinting strategies and preparation technologies. The application of MIPs in recent years (particularly the last five years) to the detection of polar pesticide residues including neonicotinoids, organophosphorus, triazines, azoles, and urea is then systematically summarized. Finally, the future development direction and trends for MIPs are proposed considering existing challenges, with the aim of providing reference to guide future research on MIPs in the field of polar pesticide residue detection.

Partially carbonized cellulose filter paper as a green adsorbent for the extraction of pesticides from fruit juices

In this study, a new solid phase extraction method based on the use of a low-cost funnel-shaped partially carbonized cellulose filter paper as a sorbent has been developed. The sorbent is easily prepared by heating the folded filter paper wetted with sulfuric acid solution and can be reused for several times. It is combined with dispersive liquid-liquid microextraction and used for the extraction of some pesticide residues from fruit juice samples prior to their analysis by gas chromatography-flame ionization detection. In this work, limits of detection and quantification were in the ranges of 0.30-0.61 and 1.0-2.0 µg L^-1, respectively, and relative standard deviations ranged between 3 and 6% for intra- (n=5) and inter-day (n=5) precisions at a concentration of 25 µg L^-1 of each pesticide. The enrichment factors of 452-751 were achieved. Extraction recoveries were in the range of 45-75%. The calibration curves had wide linear ranges with a good linearity (coefficient of determination ≥ 0.994). Finally, efficiency of the method was apprised by determining the analytes in fruit juice samples and relative recoveries were found to be in the range of 85-101%.

Hydrolysis of Amisulbrom in Buffer Solutions and Natural Water Samples: Kinetics and Products Identification

In this study, the hydrolysis of amisulbrom in buffer solutions and natural water samples were investigated. Effects of pH and temperature were tested in buffer solutions. Amisulbrom was stable in acidic and neutral aqueous solutions at 25°C, while quickly hydrolyzed with a half-life of 4.5 days (25°C) at pH 9.0. The kinetics rate equation was determined as k = 1.0234 × 10¹⁰ exp (-61.3760/R·T) (R² = 0.9642) for hydrolysis of amisulbrom at pH 9.0. The pH, ionic strength, and solubility were important factors influencing the hydrolysis of amisulbrom in natural water samples. Furthermore, three hydrolysis products were separated and identified in buffer solution (pH 9.0) and natural water samples. A tentative transformation mechanism of amisulbrom was proposed to rationalize the formation of HPs (hydrolysis products) based on their structural identification, DFT (density functional theory), and hydrolysis profiles. Toxicity prediction using the quantitative structure-activity relationship model revealed that the HP-I, and HP-II were more toxic than the parent amisulbrom. This investigation was the first to evaluate the behavior of amisulbrom hydrolysis in aquatic systems.

Preparation and application of simetryn-imprinted nanoparticles in triazine herbicide residue analysis

This work provides a simple and rapid method for synthesis uniform simetryn imprinted nanoparticles, which can be used to pretreat the tested samples before detecting. A series of computational approach were employed for design simetryn-imprinted polymer. Based on the conclusion of theoretical calculation, the simetryn imprinted nanoparticles were synthesized using simetryn as template, methacrylic acid as monomer with different solvent volume and synthesis conditions. The obtained nanoparticles have small size, uniform distribution and high imprinted factor. Scatchard analysis and quantum chemical calculations were applied for evaluating the interaction of simetryn with methacrylic acid in the imprinting process. The selectivity and recognition ability of the simetryn imprinted nanoparticles for six triazine herbicides and two other type herbicides were investigated. The results show that the simetryn imprinted nanoparticles had high selectivity and binding capacity and could be used for the separation and enrichment of four triazine pesticide residues from actual samples. A method of molecularly imprinted matrix solid phase extraction ultra-performance liquid chromatography tandem mass spectrometry was established for detecting four kinds of triazine herbicide residues in tobacco. The recovery rate of terbuthylazine, simetryn, atrazine, and prometryn in tobacco was 84.03-119.05%, and the relative standard deviation was 0.35-10.12%.

Development of fluorescent lateral flow test strips based on an electrospun molecularly imprinted membrane for detection of triazophos residues in tap water

Herein, a molecularly imprinted membrane chromatography strip using a combination of electrospinning, molecular imprinting, and fluorescent lateral flow test strips (LFTS) was developed for specific recognition of triazophos residues in tap water.

Sensitive and Simple Competitive Biomimetic Nanozyme-Linked Immunosorbent Assay for Colorimetric and Surface-Enhanced Raman Scattering Sensing of Triazophos

The biomimetic enzyme-linked immunosorbent assay (BELISA) is widely used for detection of small-molecule compounds as a result of low cost and reagent stability of molecularly imprinted polymers (MIPs). However, enzyme labels used in BELISA still suffer some drawbacks, such as high production cost and limited stability. To overcome the drawbacks, a biomimetic nanozyme-linked immunosorbent assay (BNLISA) based on MIPs and nanozyme labels was first proposed. For nanozyme labels, platinum nanoparticles (PtNPs) acted as peroxidase by catalyzing the oxidation of colorless 3,3',5,5'-tetramethylbenzidine (TMB) into an ideal surface-enhanced Raman scattering (SERS) marker. Blue TMB²⁺ and bovine serum albumin (BSA)-hapten showed superior selectivity when competing with targets for binding sites on MIPs, named the Pt@BSA-hapten probe. The BNLISA method was employed to detect triazophos with a limit of detection of 1 ng mL^-1 via colorimetric and SERS methods. Replacing traditional enzymes with nanozymes for combination with MIPs may bring about a new prospect for other compound analyses.