QuEChERS-based analytical methods developed for LC-MS/MS multiresidue determination of pesticides in representative crop fatty matrices: Olives and sunflower seeds

Facile preparation of hollow covalent organic frameworks as superior and universal matrix clean-up micro-structures for high throughout determination of food hazards

The complicated food matrix seriously limits the one-time test for the potential food hazards in non-targeted analysis. Accordingly, developing advanced sample pretreatment strategy to reduce matrix effects is of great significance. Herein, newly-integrated hollow-structured covalent organic frameworks (HCOFs) with large internal adsorption capacity and target-matched pore size were synthesized via etching the core-shell structured COFs. The as-prepared HCOFs could be directly applied for matrix clean-up of vegetable samples, while further modification of polydopamine (PDA) network facilitated application for animal samples. Both HCOFs and HCOFs@PDA with the comparable sizes to the matrix interference gave excellent adsorption performance to targets, achieving satisfied recoveries (70%-120%) toward 90 pesticides and 44 veterinary drugs in one-test, respectively. This work showed the great potential of the facile-integrated HCOFs with high stability and customized size to remove interference matrix and offered a universal strategy to achieve simultaneous screening of hazards with considerable quantity in high-throughput non-targeted analysis.

Pesticides in the environment: Degradation routes, pesticide transformation products and ecotoxicological considerations

Among rising environmental concerns, emerging contaminants constitute a variety of different chemicals and biological agents. The composition, residence time in environmental media, chemical interactions, and toxicity of emerging contaminants are not fully known, and hence, their regulation becomes problematic. Some of the important groups of emerging contaminants are pesticides and pesticide transformation products (PTPs), which present a considerable obstacle to maintaining and preserving ecosystem health. This review article aims to thoroughly comprehend the occurrence, fate, and ecotoxicological importance of pesticide transformation products (PTPs). The paper provides an overview of pesticides and PTPs as contaminants of emerging concern and discusses the modes of degradation of pesticides, their properties and associated risks. The degradation of pesticides, however, does not lead to complete destruction but can instead lead to the generation of PTPs. The review discusses the properties and toxicity of PTPs and presents the methods available for their detection. Moreover, the present study examines the existing regulatory framework and suggests the need for the development of new technologies for easy, routine detection of PTPs to regulate them effectively in the environment.

Development and validation of QuEChERS-based LC-MS/MS method for simultaneous quantification of eleven N-nitrosamines in processed fish meat, processed meat, and salted fish products

N-Nitrosamines (NAs) pose a threat to food safety due to their carcinogenic and mutagenic properties. In this study, we developed and validated a QuEChERS-based LC-MS/MS method for the simultaneous analysis of 11 NAs in 74 processed fish meat, processed meat, and salted fish products. Sample preparation was optimized by screening two versions of QuEChERS buffer, four extraction methods, and eight purification methods. The optimal analytical approach was validated for three product categories in terms of linearity, matrix effects, accuracy, and precision. Satisfactory precision and accuracy were demonstrated, with relative recoveries of 70-120% for the 11 NAs. The limits of detection for fish meat, processed meat, and salted fish products were 0.12-7.50, 0.12-4.14, and 0.10-7.81 ng·g-1, respectively. Among the 11 NAs, nine were detected in all 74 samples. This methodology could be applied to monitor NA levels to ensure the safety and quality of food products.

Neonicotinoid insecticides in plant-derived Foodstuffs: A review of separation and determination methods based on liquid chromatography

Neonicotinoids (NEOs) are the most widely used insecticides globally. They can contaminate or migrate into foodstuffs and exert severe neonic toxicity on humans. Therefore, lots of feasible analytical methods were developed to assure food safety. Nevertheless, there is a lack of evaluation that the impacts of food attributes on the accurate determination of NEOs. This review aims to provide a comprehensive overview of sample preparation methods regarding 6 categories of plant-derived foodstuffs. Currently, QuEChERS as the common strategy can effectively extract NEOs from plant-derived foodstuffs. Various enrichment technologies were developed for trace levels of NEOs in processed foodstuffs, and multifarious novel sorbents provided more possibility for removing complex matrices to lower matrix effects. Additionally, detection methods based on liquid chromatography were summarized and discussed in this review. Finally, some limitations were summarized and new directions were proposed for better advancement.

Improving analytical performance for pesticides and mycotoxins determination in Brazilian table olives: one extraction and one analysis

This paper describes an extensive study in which a multiclass QuEChERS based approach was optimized for determination of 150 pesticides and 7 mycotoxins in table olives. Three versions of QuEChERS were evaluated and compared (unbuffered, citrate and acetate buffering). A combination of EMR-Lipid cartridges and liquid nitrogen or freezer freezing out were tested for clean-up of the oily olive extracts. Analysis of the extracts were performed by LC-MS/MS triple quadrupole. The best results were achieved using acetate QuEChERS with liquid nitrogen for clean-up. For validation, organic olives were ground and spiked at 4 concentrations with pesticides and mycotoxins (n = 5). The linearity of the calibration curves was assessed by analyzing calibration standards of 7 concentrations which were prepared separately in acetonitrile and in blank olive extract (n = 5). The validation study demonstrated that the calculated r2 was ≥0.99 for 144 pesticides and 6 mycotoxins, when the calibration curves were prepared in matrix extract, showing satisfactory linearity. Matrix effects were within the range of ±20% for only 46 pesticides and one mycotoxin. Then, to ensure reliable quantification, calibration standards had to be matrix-matched. In accuracy experiments 138 pesticides and 6 mycotoxins presented recoveries from 70 to 120% and RSD ≤ 20% for at least 2 of the 4 spike concentrations evaluated, being successfully validated. The integrated QuEChERS and LC-MS/MS method meet MRL for 11 of the 21 pesticides regulated for olives in Brazil and for 132 pesticides which are regulated in the EU law. Eleven commercial table olive samples were analyzed and 4 of them tested positive for pesticides. All the positive samples violate the Brazilian law and one sample violates also the European law.

Calixarene-Based Supramolecular Sensor Array for Pesticide Discrimination

The identification and detection of pesticides is crucial to protecting both the environment and human health. However, it can be challenging to conveniently and rapidly differentiate between different types of pesticides. We developed a supramolecular fluorescent sensor array, in which calixarenes with broad-spectrum encapsulation capacity served as recognition receptors. The sensor array exhibits distinct fluorescence change patterns for seven tested pesticides, encompassing herbicides, insecticides, and fungicides. With a reaction time of just three minutes, the sensor array proves to be a rapid and efficient tool for the discrimination of pesticides. Furthermore, this supramolecular sensing approach can be easily extended to enable real-time and on-site visual detection of varying concentrations of imazalil using a smartphone with a color scanning application. This work not only provides a simple and effective method for pesticide identification and quantification, but also offers a versatile and advantageous platform for the recognition of other analytes in relevant fields.

Simple and rapid ionic liquid-based one-, two-, three-phase transition microextraction for efficient extraction of trace organic pollutants and elimination of lipid co-extractives from fatty food matrices

Extraction of trace contaminants from fatty food matrices is challenging in food analysis. Herein, a new ionic liquid-based one-, two-, three-phase transition microextraction (IL-OTTPTME) was proposed to efficiently extract trace targets while simultaneously eliminating lipid co-extractives. The method performance was illustrated through the determination of chrysoidine in fatty soybean products using high-performance liquid chromatography-ultraviolet/visible detection. The strong interactions and infinite contact between IL and chrysoidine in the one-phase system ensured ultra-high extraction efficiency (∼100 %). Density functional theoretical calculations confirmed the presence of strong hydrogen bonding and π-π interactions. The formation of the three-phase system during extraction could completely eliminate lipid co-extractives. The IL-OTTPTME integrated extraction, enrichment and cleanup steps into one step, making it rapid and extremely easy to operate. The method had a wide linear range of 0.5-5000 μg/kg and low limit of detection (0.15 μg/kg). It also had satisfactory relative recoveries (95.1 %-104.0 %) and low RSDs (≤5.0 %, n = 5).

Optimization of QuEChERS method for determination of pesticide residues in vegetables and health risk assessment

The present study focused on the optimization of the QuEChERS extraction method for the determination of 61 pesticide residues and associated health risk assessment in 144 samples of commonly consumed vegetables, viz., eggplant, cabbage, green chilli, okra, and tomato. The samples were collected between January and April 2022 from three different districts within Gujarat, India. The QuEChERS method was optimized and utilized for the extraction of samples. The samples were analyzed by UHPLC-q-TOF/MS and GC-MS/MS. The modified QuEChERS method was successfully validated, and the obtained results were satisfactory as per the 2021 SANTE guidelines. The residue analysis of the vegetable samples showed that about 4% of total samples contained single pesticide residues. Pesticide residues below the quantitation limit (BQL) were observed in eggplant, cabbage, and okra samples. In total, 15.62% (n = 5) samples of green chilli showed the presence of pesticides such as azoxystrobin, bifenthrin, cypermethrin, fenpropathrin, and propargite whereas 3% (n = 1) tomato samples contained cyfluthrin. In total, 97.22% of the samples had residues that were below the European Union Maximum Residue Limit (EU MRL). Two samples of green chilli had pesticide residues above EU MRL. The Hazard Index (HI) and Hazard Quotient (HQ) were used to assess the health risks associated with green chilli and tomato consumption. The HI and HQ values for adolescents and adults were found to be less than 1. The modified QuEChERS method was found to be easy and effective and can be implemented for routine sample analysis. The study revealed the presence of pesticide residues in tomato and green chilli samples. Further, the outcome provided information pertaining to current pesticide status, concluding that consumption of these commodities is unlikely to pose any health risk, though long-term monitoring studies focusing on dietary health risk assessment must be initiated.

Optimization of a QuEChERS-LC-MS/MS method for 51 pesticide residues followed by determination of the residue levels and dietary intake risk assessment in foodstuffs

A modified QuEChERS purification-liquid chromatography-tandem mass spectrometry method has been developed to determine 51 pesticide residues with newly established maximum residue limits (MRLs) in foodstuffs. Samples were extracted with acetonitrile under citrate-buffered conditions and purified using a modified QuEChERS method employing hydroxylated MWCNTs, SAX, and C18. The limits of quantification ranged from 0.2 to 9.8 µg/kg. Recoveries in ten different foodstuffs ranged from 70.2% to 117.9%, with relative standard deviations between 2.3% and 19.9% at three spiking levels. This method was applied to analyze 352 market samples, detecting 14 pesticides in 97 samples. Notably, Afidopyropen, cyantraniliprole, and fluxapyroxad residues in vegetables exhibited a consistent pattern of higher levels in the spring and winter and lower levels in the summer and autumn. Moreover, the risk assessments for acute and chronic dietary exposure to the 14 detected pesticides indicated that the %ADI and %ARfD were well below 100%.

Profiling of Volatile Compounds in 'Muscat Hamburg' Contaminated with Aspergillus carbonarius before OTA Biosynthesis Based on HS-SPME-GC-MS and DLLME-GC-MS

Aspergillus carbonarius is known to produce the carcinogenic ochratoxin A (OTA) in grapes. The metabolism process before OTA biosynthesis influences the content and composition of the volatile compounds in grapes. In this study, a self-established method based on QuEChERS coupled with high-performance liquid chromatography-fluorescence detection (HPLC-FLD) was used to determine the OTA levels during a seven-day contamination period. The results showed that OTA was detected on the second day after contamination with A. carbonarius. Thus, the first day was considered as the critical sampling timepoint for analyzing the volatiles in grapes before OTA biosynthesis. Additionally, the volatile compounds in grapes were analyzed using headspace solid-phase microextraction gas chromatography-mass spectrometry (HS-SPME-GC-MS) and dispersive liquid-liquid microextraction gas chromatography-mass spectrometry (DLLME-GC-MS). The corresponding data were evaluated via multivariate data analysis using projection methods, including PCA and OPLS-DA. The results indicated significant differences in the nine volatile compounds in grapes contaminated with A. carbonarius before OTA biosynthesis. The results of the Pearson correlation analysis showed positive correlations between ethyl acetate, styrene, 1-hexanol and OTA; (E)-2-hexenal and nerolic acid were negatively correlated with OTA. Overall, these findings provide a theoretical basis for the early prediction of OTA formation in grape and grape products using GC-MS technology.

A Novel and Highly Efficient Microextraction Method for the Determination of Aflatoxin Precursor Averantin in Fatty Grain Samples

Averantin (AVN) is an important aflatoxin biosynthetic precursor and has been listed in the screening range of mycotoxins. Herein, a novel ionic liquid-based one-, two-, and three-phase transition microextraction (IL-OTTPTME) method was combined with high-performance liquid chromatography for the extraction and determination of AVN in fatty grain samples. The formation of a homogeneous solution and three-phase system during the IL-OTTPTME process allowed both efficient extraction and coextracted lipid cleanup. Density functional theory calculations and distribution coefficient determination results demonstrated that AVN extraction by IL mainly occurred through hydrogen-bond and π-π interactions. Under optimized conditions, the LOD and LOQ of the proposed method were 0.5 and 1.5 ng/g, respectively. Finally, the method was used to determine AVN in several grains with different fat contents, achieving satisfactory relative recoveries (86.0-107.8%) and RSDs (1.2-6.2%, n = 3).

Developments in food neonicotinoids detection: novel recognition strategies, advanced chemical sensing techniques, and recent applications

Neonicotinoid insecticides (NEOs) are a new class of neurotoxic pesticides primarily used for pest control on fruits and vegetables, cereals, and other crops after organophosphorus pesticides (OPPs), carbamate pesticides (CBPs), and pyrethroid pesticides. However, chronic abuse and illegal use have led to the contamination of food and water sources as well as damage to ecological and environmental systems. Long-term exposure to NEOs may pose potential risks to animals (especially bees) and even human health. Consequently, it is necessary to develop effective, robust, and rapid methods for NEOs detection. Specific recognition-based chemical sensing has been regarded as one of the most promising detection tools for NEOs due to their excellent selectivity, sensitivity, and robust interference resistance. In this review, we introduce the novel recognition strategies-enabled chemical sensing in food neonicotinoids detection in the past years (2017-2023). The properties and advantages of molecular imprinting recognition (MIR), host-guest recognition (HGR), electron-catalyzed recognition (ECR), immune recognition (IR), aptamer recognition (AR), and enzyme inhibition recognition (EIR) in the development of NEOs sensing platforms are discussed in detail. Recent applications of chemical sensing platforms in various food products, including fruits and vegetables, cereals, teas, honey, aquatic products, and others are highlighted. In addition, the future trends of applying chemical sensing with specific recognition strategies for NEOs analysis are discussed.

Matrix effects demystified: Strategies for resolving challenges in analytical separations of complex samples

Matrix effects can significantly impede the accuracy, sensitivity, and reliability of separation techniques presenting a formidable challenge to the analytical process. It is crucial to address matrix effects to achieve accurate and precise measurements in complex matrices. The multifaceted nature of matrix effects which can be influenced by factors such as target analyte, sample preparation protocol, composition, and choice of instrument necessitates a pragmatic approach when analyzing complex matrices. This review aims to highlight common challenges associated with matrix effects throughout the entire analytical process with emphasis on gas chromatography-mass spectrometry, liquid chromatography-mass spectrometry, and sample preparation techniques. These techniques are susceptible to matrix effects that could lead to ion suppression/enhancement or impact the analyte signal at various stages of the analytical workflow. The assessment, quantification, and mitigation of matrix effects are necessary in developing any analytical method. Strategies can be implemented to reduce or eliminate the matrix effect by changing the type of ionization, improving extraction and clean-up methods, optimization of chromatography conditions, and corrective calibration methods. While development of an effective strategy to completely mitigate matrix effects remains elusive, an integrated approach that combines sample preparation, analytical extraction, and effective instrumental analysis remains the most promising avenue for identifying and resolving matrix effects.

Analysis of Migrant Cyclic PET Oligomers in Olive Oil and Food Simulants Using UHPLC-qTOF-MS

Oligomers are a particular category of non-intentionally added substances (NIAS) that may be present in food contact materials (FCMs), such as polyethylene terephthalate (PET), and consequently migrate into foods. Here, an ultra-high-pressure liquid chromatography quadruple time-of-flight mass spectrometry (UHPLC-qTOF-MS) method was developed for the analysis of 1st series cyclic PET oligomers in virgin olive oil (VOO) following a QuEChERS clean-up protocol. Oligomer migration was evaluated with two different migration experiments using bottles from virgin and recycled PET: one with VOO samples stored in household conditions for a year and one using the food simulant D2 (95% v/v ethanol in water) at 60 °C for 10 days. Calibration curves were constructed with fortified VOO samples, with the LOQs ranging from 10 to 50 µg L^-1 and the recoveries ranging from 86.6 to 113.0%. Results showed no migration of PET oligomers in VOO. However, in the simulated study, significant amounts of all oligomers were detected, with the migration of cyclic PET trimers from recycled bottles being the most abundant. Additional substances were tentatively identified as linear derivatives of PET oligomers. Again, open trimer structures in recycled bottles gave the most significant signals.

A high-performance Calix@ZnO based bifunctional nanomaterial for selective detection and degradation of toxic azinphos methyl in environmental samples

One of the key tenets of sustainable agriculture and food safety is the removal of toxic pesticides from the environment. However, developing reliable, affordable, and efficient methods for detecting and degrading pesticides into non-toxic degradable products remains an immediate matter of concern. Herein, we attempt to develop a strategy for the detection as well as degradation of highly toxic phosphorodithioate pesticide, Azinphos methyl (AZM), using hybrid zinc oxide nanoparticles (ZnO NPs). Considering the non-selectivity of bare ZnO and receptor R1, we have fabricated the heterocalixarene-based Calix (R1) over zinc oxide (ZnO) surface in situ via the sol-gel process. The synthesized heterocaliaxrene-modified ZnO (R1@ZnO) NPs show an excellent affinity for the selective and sensitive detection of AZM with a tremendously low limit of detection (68 mg L^-1) and no interference from other pesticides. Degradation of AZM was fully supported by fluorescence spectroscopy, scanning electron microscopy (SEM), ¹H NMR titrations, FTIR spectroscopy, cyclic voltammetry, and mass spectroscopy, which unequivocally confirmed the formation of non-toxic products. According to our findings, R1@ZnO NPs are sustainable nanomaterials that can be employed for environmental remediation since they operate in an aqueous medium.

Quality Control of Pesticide Residue Measurements and Evaluation of Their Results

Pesticide residues are monitored in many countries around the world. The main aims of the programs are to provide data for dietary exposure assessment of consumers to pesticide residues and for verifying the compliance of the residue concentrations in food with the national or international maximum residue limits. Accurate residue data are required to reach valid conclusions in both cases. The validity of the analytical results can be achieved by the implementation of suitable quality control protocols during sampling and determination of pesticide residues. To enable the evaluation of the reliability of the results, it is not sufficient to test and report the recovery, linearity of calibration, the limit of detection/quantification, and MS detection conditions. The analysts should also pay attention to and possibly report the selection of the portion of sample material extracted and the residue components according to the purpose of the work, quality of calibration, accuracy of standard solutions, and reproducibility of the entire laboratory phase of the determination of pesticide residues. The sources of errors potentially affecting the measured residue values and the methods for controlling them are considered in this article.

Residue and Risk Assessment of Fluopyram in Carrot Tissues

This study describes the variation in residue behavior of fluopyram in soil, carrot root, and carrot leaf samples after the application of fluopyram (41.7% suspension, Bayer) by foliar spray or root irrigation at the standard of 250.00 g active ingredient per hectare (a.i./ha) and double-dose treatment (500.00 g a.i./ha). Fluopyram and its metabolite fluopyram-benzamide were extracted and cleaned up using the QuEChERS method and subsequently quantified with LC-QQQ-MS/MS. The LOD and LOQ of the developed method were in the range of 0.05–2.65 ug/kg and 0.16–8.82 ug/kg, respectively. After root irrigation, the final residues detected in edible parts were 0.60 and 1.80 mg/kg, respectively, when 250.00 and 500.00 g a.i./ha were applied, which is much higher than the maximum residue limit in China (0.40 mg/kg). In contrast, after spray application, most of the fluopyram dissipated from the surface of carrot leaves, and the final residues in carrot roots were both only 0.05 mg/kg. Dietary risk assessments revealed a 23–40% risk quotient for the root irrigation method, which was higher than that for the foliar spray method (8–14%). This is the first report comparing the residue behavior of fluopyram applied by root irrigation and foliar spray. This study demonstrates the difference in risk associated with the two application methods and can serve as a reference for the safe application of fluopyram.