Determination of pyrethrin and pyrethroid residues in animal fat using liquid chromatography coupled to tandem mass spectrometry

Pesticide residues in animal-derived food: Current state and perspectives

Pesticides are widely used in the cultivation and breeding of agricultural products all over the world. However, their direct use or indirect pollution in animal breeding may lead to residual accumulation, migration, and metabolism in animal-derived foods, posing potential health risks to humans through the food chain. Therefore, it is necessary to detect pesticide residues in animal-derived food using simple, reliable, and sensitive methods. This review summarizes sample extraction and clean-up methods, as well as the instrumental determination technologies such as chromatography and chromatography-mass spectrometry for residual analysis in animal-derived foods, including meat, eggs and milk. Additionally, we perspectives on the future of this field. This information aims to assist relevant researchers in this area, contribute to the development of ideas and novel technical methods for residual detection, metabolic research and risk assessment of pesticides in animal-derived food.

Surface-enhanced Raman spectroscopy as a powerful method for the analysis of Chinese herbal medicines

Chinese herbal medicines (CHMs) derived from nature have received increasing attention and become more popular. Due to their diverse production processes, complex ingredients, and different storage conditions, it is highly desirable to develop simple, rapid, efficient and trace detection methods to ensure the drug quality. Surface-enhanced Raman spectroscopy has the advantages of being time-saving, non-destructive, usable in aqueous environments, and highly compatible with various biomolecular samples, providing a promising analytical method for CHM. In this review, we outline the major advances in the application of SERS to the identification of raw materials, detection of bioactive constituents, characterization of adulterants, and detection of contaminants. This clearly shows that SERS has strong potential in the quality control of CHM, which greatly promotes the modernization of CHM.

Distribution and Elimination of Deltamethrin Toxicity in Laying Hens

Deltamethrin, an important pyrethroid insecticide, is frequently detected in human samples. This study aims to assess the potential effects of deltamethrin on human health and investigate the patterns of residue enrichment and elimination in 112 healthy laying hens. These hens were administered 20 mg·kg-1 deltamethrin based on their body weight. Gas chromatography-mass spectrometry (GC-MS) was used to investigate the residue enrichment pattern and elimination pattern of deltamethrin in the hens. The results indicated a significant increase in the concentration of deltamethrin in chicken manure during the treatment period. By the 14th day of administration, the concentration of deltamethrin in the stool reached 13,510.9 ± 172.24 μg·kg-1, with a fecal excretion rate of 67.56%. The pulmonary deltamethrin concentration was the second highest at 3844.98 ± 297.14 μg·kg-1. These findings suggest that chicken feces contain substantial amounts of deltamethrin after 14 days of continuous administration, and that it can easily transfer to the lungs. After 21 days of drug withdrawal, the residual concentration of deltamethrin in the fat of laying hens was 904.25 ± 295.32 μg·kg-1, with a half-life of 17 days and a slow elimination rate. In contrast, the lungs showed relatively low elimination half-lives of 0.2083 days, indicating faster elimination of deltamethrin in this tissue. These results highlight differences in the rate of deltamethrin elimination in different tissues during drug withdrawal. The fat of laying hens exhibited the highest residue of deltamethrin and the slowest elimination rate, while the lungs showed the fastest elimination rate. Moreover, deltamethrin was found to accumulate in the edible tissues of eggs and laying hens, suggesting that humans may be exposed to deltamethrin through food.

Simultaneous Determination of Pyrethrins, Pyrethroids, and Piperonyl Butoxide in Animal Feeds by Liquid Chromatography-Tandem Mass Spectrometry

The presence of insecticides like pyrethrins and synthetic pyrethroids, combined with the synergist piperonyl butoxide, in animal feeds can pose a risk to both animal and human health by contaminating the food chain. In this study, a simple and fast method was developed for the simultaneous determination of these compounds in contaminated animal feeds using liquid chromatography-tandem mass spectrometry (LC-MS/MS). Sample preparation was carried out using a QuEChERS-based approach, and the method was validated with acceptable accuracy ranging from 84 to 115% and precision below 10%. The limit of detection (LOD) and limit of quantification (LOQ) were between 0.15 and 3 and 1 and 10 µg/kg, respectively. The method detected insecticide contaminations in various livestock and poultry feeds. Furthermore, the method was applied to a toxicology case, where it identified and quantified piperonyl butoxide and deltamethrin in the submitted horse feed sample. These results demonstrate that the method can be a valuable tool in animal health and food safety diagnostic applications, as well as veterinary toxicology investigations concerning pyrethrin-related feed contamination.

Simultaneous Determination of Pyrethroid Insecticides in Foods of Animal Origins Using the Modified QuEChERS Method and Gas Chromatography-Mass Spectrometry

Pyrethroid insecticides are used in agriculture to treat parasites in livestock. This study developed a simultaneous residue analysis method to measure seventeen pyrethroid insecticides in foods of animal origin, including beef, pork, chicken, milk, and eggs. The method, which comprises instrumental analysis using gas chromatography-tandem mass spectrometry and a modified QuEChERS (quick, easy, cheap, effective, rugged, and safe) method for pretreatment, was optimized to verify the applicability of the method. A mixture of acetonitrile, ethyl acetate, and original salt (MgSO4 4 g, NaCl 1 g) was used as the extraction solvent and salt. MgSO4 (150 mg) primary secondary amine (25 mg) and graphitized carbon black (25 mg) were selected for dispersive solid phase extraction (d-SPE). The method limit of quantitation was 0.01 mg/L, and the linearity of the matrix-matched calibration curves was reasonable (R2 > 0.99). Recovery tests were performed at three concentrations (LOQ, 10 LOQ, and 50 LOQ). Good recoveries (75.2109.8%) and reproducibility (coefficient of variation <10%) were obtained. The matrix effects were in the range of −35.8 to 56.0%. The established method was fully validated and can be used as an official analytical method for quantifying pyrethroid insecticides in animal commodities.

Hydrogen bonds-triggered differential extraction efficiencies for bifenthrin by three polymeric ionic liquids with varying anions based on FT-IR spectroscopy

Herein, we fabricated three imidazolium-based polymeric ionic liquids (PILs) with different anions (P[VEIM]BF4, P[VEIM]PF6 and P[VEIM]Br), and analyzed their differential extraction efficiencies for bifenthrin through H-bonding induced effects. Three PILs all presented an irregular block structure with rough surface and lower specific-surface area (SSA, 11.2-18.7 m2 g-1) than carbon-based nanomaterials. They formed hydrogen bonds with free-water molecules in the lattice of PILs, including C2,4,5-H⋯O-H, Br⋯H-O-H⋯Br, O-H⋯Br, C2,4,5-H⋯F-P, P-F⋯H-O-H⋯F-P, C2,4,5-H⋯F-B and B-F⋯H-O-H⋯F-B. After extraction, the O-H stretching-vibration peak was prominently intensified, whereas the C-H bond varied slightly concomitant with reduced B-F and P-F vibration. Theoretically, the C-H vibration should become more intense in the C4,5-H⋯H2O and C2-H⋯H2O bonds after extraction in contrast to before extraction. These contrary spectral changes demonstrated that the hydrogen bonds between cations in the PILs and free-water molecules were broken after extraction, yielding the H-bonding occurrence between bifenthrin and H-O-H in the lattice. As a time indicator for the free-water binding and releasing process, the highest slope for the plot of I t /I 0 against time implied that the shortest time was required for P[VEIM]PF6 to reach an adsorption equilibrium. Overall, the strong hydrophobicity, small SSA and electrostatic-repulsion force for P[VEIM]PF6 are all not conducive to its efficient adsorption. Beyond our anticipation, P[VEIM]PF6 provided the highest extraction recovery for bifenthrin up to 92.4% among three PILs. Therefore, these data lead us to posit that the above high efficiency results from the strongest H-bonding effect between P[VEIM]PF6 and bifenthrin. These findings promote our deep understanding of PILs-triggered differential efficiency through a H-bonding induced effect.

Development and validation of a quantitative method for 15 antiviral drugs in poultry muscle using liquid chromatography coupled to tandem mass spectrometry

The objective of this work was to develop a quantitative multi-residue method for analysing antiviral drug residues and their metabolites in poultry meat samples. Antiviral drugs are not licensed for the treatment of influenza in food producing animals. However, there have been some reports indicating their illegal use in poultry. In this study, a method was developed for the analysis of 15 antiviral drug residues in poultry muscle (chicken, duck, quail and turkey) using liquid chromatography coupled to tandem mass spectrometry. This included 13 drugs against influenza and associated metabolites, but also two drugs employed for the treatment of herpes (acyclovir and ganciclovir). The method required the development of a novel chromatographic separation using a hydrophilic interaction chromatographic (HILIC) BEH amide column, which was necessary to retain the highly polar compounds. The analytes were detected using a triple quadrupole mass spectrometer operating in positive electrospray ionization mode. A range of different sample preparation protocols suitable for polar compounds were evaluated. The most effective procedure was based on a simple acetonitrile-based protein precipitation step followed by a further dilution in a methanol/water solution. The confirmatory method was validated according to the EU 2021/808 guidelines on different species including chicken, duck, turkey and quail. The validation was performed using various calibration curves ranging from 0.1 µg kg^-1to 200 µg kg^-1, according to the analyte. Depending on the analyte sensitivity, decision limits achieved ranged from 0.12 µg kg^-1 for arbidol to 34.7 µg kg^-1 for ribavirin. Overall, the reproducibility precision values ranged from 2.8% to 22.7% and the recoveries from 84% to 127%. The method was applied to 120 commercial poultry samples from the Irish market, which were all found to be residue-free.

Solution decomposition of deep eutectic solvents in pH-induced solidification of floating organic droplet homogeneous liquid-liquid microextraction for the extraction of pyrethroid pesticides from milk

In this study, a pH-induced solidification of floating organic droplet homogeneous liquid-liquid microextraction procedure using deep eutectic solvent decomposition was developed for the extraction of five pyrethroid insecticides from milk samples prior to their analysis by using a gas chromatography-flame ionization detector. To reach this goal, the sample was transferred into a glass test tube and its proteins were precipitated with trichloroacetic acid. After centrifugation, the supernatant phase was transferred into another test tube and a few microliters of menthol: p-aminophenol deep eutectic solvent were dissolved in the solution and shaken to obtain a homogeneous solution. Then a few microliters of ammonia solution were added to the solution and the mixture was sonicated to break down the homogeneous solution. By doing so, the deep eutectic solvent was decomposed and menthol was formed throughout the solution as tiny droplets. In the following, the tube was transferred into an ice bath to solidify the extraction solvent on the solution surface. The collected phase was removed and melted at room temperature and an aliquot of it was analyzed by using a determination system. The validation outcomes confirmed that the method provides high extraction recoveries (72-84%) and high enrichment factors (257-299) with acceptable repeatability (relative standard deviations ≤6.4%). Low limits of detection (1.1-2.4 ng mL^-1) and quantification (3.6-8.1 ng mL^-1) were obtained using this approach. Finally, several milk samples were analyzed and deltamethrin was successfully determined in some samples.

Z-sep+ based QuEChERS technique for the pre-concentration of malathion pesticide in fruits followed by analysis using UV-Vis spectroscopy

In this work, the concentrations of malathion in fruits were determined using UV-Vis spectrophotometry prior to pre-concentration using QuEChERS. The Z-sep⁺/PSA sorbent combination was used for the d-SPE clean-up and extraction was done using acetonitrile during QuEChERS. The absorbance of malathion was measured using a UV-Vis spectrophotometer at a wavelength of 415 nm. The QuEChERS parameters, which included type and volume of extraction solvent, type and mass of sorbents, and centrifugation rate, were optimised prior to application of the developed method to real fruit samples. The linear range was from 0.1 to 0.9 mg kg^-1 while the coefficient of determination (R²) was 0.9999. The limit of detection (LOD) for malathion was found to be 0.017 mg kg^-1 and the limit of quantification was 0.05 mg kg^-1. Orange samples were found to have no malathion residues when the developed method was applied to them while the concentrations of malathion in apple and pear samples were 0.07 mg kg^-1 and 0.09 mg kg^-1 respectively.

Quantification of deltamethrin residues in wheat by Ag@ZnO NFs-based surface-enhanced Raman spectroscopy coupling chemometric models

Deltamethrin, one of the most toxic pyrethroids, is commonly used to inhibit pests in wheat. However, the trace levels of deltamethrin in wheat is alarming to human health. In this study, surface-enhanced Raman spectroscopy (SERS)-active silver nanoparticles-plated-zinc oxide nanoflowers (Ag@ZnO NFs) nano-sensor were employed for rapid and sensitive quantification of deltamethrin in wheat. To sufficiently utilize the chemical-related information in SERS spectra, various spectral pretreatment and chemometric models were studied. The mean centering (MC) coupling successive projection algorithm-partial least squares regression (SPA-PLS) provided optimal predictive performance (correlation coefficient of prediction (Rp) = 0.9736 and residual predictive deviation (RPD) = 4.75). The proposed method achieved the limit of detection (LOD) = 0.16 μg·kg^-1, the recovery of predicted results was in the range of 96.33-109.17% and the relative standard deviation (RSD) was < 5%. The overall results suggested that SERS based Ag@ZnO NFs combined with MC-SPA-PLS could be an easy and efficient method to quantify deltamethrin residue levels in wheat.

Multi-Residue Screening of Pesticides in Aquaculture Waters through Ultra-High-Performance Liquid Chromatography-Q/Orbitrap Mass Spectrometry

Pesticide residues in foodstuffs can lead to several undesirable effects. A simple and high-throughput targeted screening method analyzing multi-residue pesticide in aquaculture water based on ultra-high-performance liquid chromatography-Q/Orbitrap mass spectrometry (UHPLC-Q/Orbi MS) was developed and validated. In this technique, the peaks of the compound using precursor ions were recorded by the full scan, which was used for rough quantitative analysis with single point matrix matched calibration. The qualitative identification was performed following the stringent confirmation criteria with fragment ions, retention time, and an isotopic pattern. Additionally, solid-phase extraction with an HLB (Hydrophilic/Lipophilic Balanced) column was selected to enrich and separate target pesticides from water. The screening detection limit of 33 compounds are less than 2 ng·L−1, while 26 compounds range from 2 ng·L−1 to 10 ng·L−1, 19 compounds are at the range of 10–200 ng·L−1, and the other two compounds are 200 ng·L−1 and 1000 ng·L−1. Most of the recovery results were found to be between 60~130%. Finally, the method was successfully applied to the analysis of pesticide residues in 30 water samples from aquaculture environment in Shanghai, indicating its applicability in pesticide screening for environmental monitoring.

Supercritical Fluid Chromatography and Gas Chromatography Coupled to Tandem Mass Spectrometry for the Analysis of Pyrethroids in Vegetable Matrices: A Comparative Study

This study describes a comprehensive comparison between supercritical fluid chromatography (SFC) and gas chromatography (GC) coupled to mass spectrometry for the analysis of pyrethroids in vegetable matrices. The ionization process used was electrospray ionization (ESI) in SFC and electron ionization in GC. In general, liquid chromatography coupled to mass spectrometry with ESI sources provides poor results for pyrethroid detection, as described in previous literature. A total of 14 pyrethroids were selected, together with 6 representative matrices. The differences in chromatographic separation and ionization process were assessed. Similar results were obtained in terms of sensitivity (limits of quantification close to 2 μg/kg, injecting the same amount of sample), matrix effect, and linearity. A total of 17 real samples were analyzed by both systems, obtaining similar results. These data suggest that SFC offers a suitable alternative to GC in the analysis of pyrethroids and allows for their inclusion in a wider multiresidue method.

Novel Liquid Chromatography-Tandem Mass Spectrometry Method for Enantioseparation of Tefluthrin via a Box-Behnken Design and Its Stereoselective Degradation in Soil

A simple and eco-friendly dispersive solid-phase extraction method coupled with ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed for the determination of the chiral pesticide tefluthrin in food and environmental samples. The response surface methodology was applied to optimize separation conditions. The elution order of tefluthrin enantiomers was Z-cis-(1S,3S)-(-)-tefluthrin and Z-cis-(1R,3R)-(+)-tefluthrin on a Lux Cellulose-1 chiral column was identified via a polarimeter and vibrating circular dichroism. The average recoveries in five matrices ranged from 76.9 to 107.6%, with intraday relative standard deviations (RSDs) less than 15.6% and interday RSDs less than 12.5% for two enantiomers. The enantioselective degradation was investigated via laboratory incubation experiments. Slightly enantioselective degradation was observed under aerobic conditions; (1S,3S)-tefluthrin degraded preferentially with the enantiomer fraction value of 0.57 at 120 days of incubation. No remarkable enantioselective degradation was observed under anaerobic and sterile conditions. It was the first time that pyrethroid pesticides were determined at the enantiomer levels via UPLC-MS/MS. This novel method was successfully applied for the enantioselective analysis of tefluthrin enantiomers in authentic samples, indicating its efficacy in investigating the environmental stereochemistry of tefluthrin in the food web and environment. It is of crucial importance to improve risk assessment and regulation of chiral pesticides in an agricultural system.

Vibrational extraction QuEChERS for analysis of antiparasitic agents in fish by liquid chromatography coupled with tandem mass spectrometry

A method was developed for the analysis of 22 antiparasitic residues belonging to the benzoylurea, organophosphate, pyrimidinamine, pyrethrin and pyrethroid classes in salmon by liquid chromatography coupled with tandem mass spectrometry. Samples were extracted with acetonitrile-water as the extraction solvent with use of a vibrational shaking apparatus with a ceramic homogenizer. After extraction, the acetonitrile extracts were cleaned up by incubation at low temperature (-20 °C, 1 h) to remove fat, followed by dispersive solid-phase extraction using Z-Sep+ and primary-secondary amine as sorbents. Validation was performed following the 2002/657/EC and SANTE/11813/2017 guidelines. The trueness of the method ranged from 87% to 121% and precision ranged from 4.1% to 23.7%, with the exception of cyphenothrin, dicyclanil and azamethiphos. The method developed is particularly advantageous because the use of a vibrational shaker allows unattended extraction of samples and eliminates a laborious tissue disruption step, which increases sample throughput in the laboratory. The sample preparation and chromatographic separations can be performed in 5 and 4 h, respectively, for 36 samples. Graphical abstract.

Development and validation of a method for the analysis of pyrethroid residues in fish using GC-MS

The presence of the pyrethroids residues in different samples and the impact on human health is an increasing concern due to their widespread use. So, a method to determine eighteen pyrethroids in fish samples using a modified QuEChERS was developed. The clean-up procedure was performed by freezing samples overnight followed by dispersive solid phase extraction. The combination of C₁₈, PSA and Z-Sep+ was optimized using a mixture design approach and samples were analysed using gas chromatography mass spectrometry. The method was validated using trahira samples and a scope extension was performed for tilapia and tainha. Recoveries were within 63-129%, relative standard deviation was ≤21.5% and the quantification limits were 5 µg kg^-1 or 10 µg kg^-1. The applicability of the method was assessed by analysis of fourteen real samples, in which residues were detected in four samples. Such detections demonstrate the importance of this sensitive method.