Analysis of pesticide and veterinary drug residues in baby food by liquid chromatography coupled to Orbitrap high resolution 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.

Multi-class/residue method for determination of veterinary drug residues, mycotoxins and pesticide in urine using LC-MS/MS technique

BACKGROUND

Veterinary drugs are widely used in animals to prevent diseases and are a complex set of drugs with very different chemical properties. Multiclass and multi-residue methods for simultaneous detection of residues from veterinary drugs and contaminants in urine are very rare or non-existent. Therefore, the aim of this study was to develop and validate a sensitive and reliable quantitative LC-MS/MS method for simultaneous determination of a wide range of veterinary drug and pesticide residues and mycotoxins in bovine urine. This involved 42 veterinary drug residues (4 thyreostats, 6 anabolic hormones, 2 lactones, 10 beta agonists, 15 antibiotics, 5 sulphonamides), 28 pesticides and 2 mycotoxins. Stable isotopically labelled internal standards were used to facilitate effective quantification of the analytes. Analysis was performed in both positive and negative ionization modes with multiple reaction monitoring transitions over a period of 12 min.

RESULTS

The parameters validated included linearity, limit of detection (LOD), limit of quantification (LOQ), detection capability (CCβ), decision limit (CCα), stability, accuracy and precision. The process followed guidelines of the regulation 2021/808/EC. The calibration curves were linear with coefficient of correlation (R2) from 0.991 to 0.999. The LODs were from 0.01 to 2.71 µg/L, while the LOQs were from 0.05 to 7.52 µg/L. The CCα and CCβ were in range 0.05-12.11 µg/L and 0.08-15.16 µg/L. In addition, the average recoveries of the spiked urine samples were from 71.0 to 117.0% and coefficient of variation (CV) < 21.38% (intraday and interday).

CONCLUSION

A new isotopic LC-MS/MS method has been developed, validated and applied for identification and quantification of 72 residues of veterinary drugs and pesticides and other contaminants such as mycotoxins in bovine urine. The most appropriated sample preparation procedures involved sodium acetate buffer, enzymatic hydrolysis using β-glucuronidase and cleanup solid phase extraction with OASIS SPE cartridges. The parameters were satisfactorily validated fulfilling requirements under Regulation 2021/808/EC. Consequently, the method could be used in routine analysis of bovine urine samples for simultaneous detection of veterinary drug and pesticide residues as well as contaminants such as mycotoxins.

Simultaneous Determination of Multiple Contaminants in Chicken Liver Using Dispersive Liquid-Liquid Microextraction (DLLME) Detected by LC-HRMS/MS

Simultaneous determination of a mixture of food contaminants, including pesticides, sulphonamides, fluoroquinolones, anthelmintics, and aflatoxin B1, in solid biological samples (chicken liver) by dispersive liquid-liquid microextraction/liquid chromatography-high resolution mass spectrometry (DLLME/LC-HRMS) is presented. Previous work focused on the application of DLLME to single-class contaminants. In this work, the DLLME extraction method has been extended to complex multiresidues in the biological matrix. The first part of this study was the selection of an appropriate solvent that enabled the dissolution of analytes from the chicken livers. The matrix-matched calibration curves showed good linearity in the range 0.5-50.0 µg kg^-1 for aflatoxin B1 and 50-500 µg kg^-1 for pesticides, fluoroquinolones, sulphonamides, and anthelmintics, with a coefficient of determination (R²) values of 0.9916-0.9967. The mean recoveries were in the range of 80.4-96.3%, and the relative standard deviation (RSD) values were in the range of 1.53-8.98%. The limit of detection (LOD) and the limit of quantification (LOQ) values were 0.03 µg kg^-1 and 0.09 µg kg^-1, respectively, for aflatoxin B1, and for pesticides, fluoroquinolones, sulphonamides, and anthelmintics, they were in the range of 0.011-1.197 µg kg^-1 and 0.150-2.579 µg kg^-1, respectively. The developed method was compared with the standard solid phase extraction (SPE) method, and there was no significant difference between the two methods.

[Determination of multi-veterinary drug residues in complementary foods for infants and young children by ultra performance liquid chromatography-tandem mass spectrometry]

Special attention must be paid to children and infants because health issues stemming from a poor immunologic system and low weight make them a vulnerable risk group. Complementary foods for infants and young children, which are a class of special dietary foods, are essential transitional foods for infants from lactation to adaptation to ordinary food. Some complementary foods for infants and young children are of animal origin such as fish, meat, and the liver, which may contain veterinary drug residues. Veterinary drugs are usually small-molecular-weight chemicals that are essential for treating infections, increasing production, and improving animal husbandry. However, abuse of these substances can provoke transfer to the food chain, leading to negative consequences for humans, especially infants and young children. For a more comprehensive safety supervision of infant supplementary foods, a method based on ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) was developed and used for the determination of 50 antibiotics and antivirals (grouped into six categories: fluoroquinolones, sulfonamides, macrolides, nitroimidazoles, chloramphenicols, and antivirals) in complementary foods for infants and young children. The matrix of complementary foods for infants and young children is complex and contains a large number of proteins and lipids, which poses a serious challenge for sample pretreatment. The Captiva EMR-Lipid solid-phase extraction (SPE) column is a new type of product that allows for selective and efficient lipid/matrix removal without negatively affecting the recovery of the analyte. In this study, samples were extracted with acidified acetonitrile and then purified using a Captiva EMR-Lipid SPE column. The target analytes were separated on a BEH C18 column by gradient elution using acetonitrile and water containing 0.1% (v/v) formic acid as the mobile phases. MS detection was performed with an electrospray source in the positive and negative modes in the multireaction monitoring (MRM) mode. The ion spray voltages were set at 5500 V and -4500 V in the positive and negative modes, respectively. The source temperature for both the ionization modes was set to 500 ℃. Instrumental parameters such as collision energy and declustering potential were optimized. The samples were quantified using the external standard method with matrix calibration curves to reduce the influence of the matrix effect on the quantitative results.The results showed that the 50 veterinary drug residues had good linear relationships in the range of 0.5 to 50 μg/L, with correlation coefficients higher than 0.995. The limits of detection (LODs) and quantification (LOQs) were in the range of 0.03-0.70 μg/kg and 0.09-2.33 μg/kg, respectively. The average recoveries for all the compounds under different matrices ranged from 64.37% to 119.3% at spiked levels of 5 μg/kg and 50 μg/kg, with relative standard deviations of less than 15%. Compared to QuEChERS, this method has a better purification effect. The recoveries of the 50 veterinary drugs extracted by this method were also much higher than those in the case of QuEChERS. This method was applied to the detection of 14 domestic and six imported infant supplementary foods. Sulfaquinoxaline, sulfamethazine, and tilmicosin were detected in one imported meat-based baby food. With its simple operation, high sensitivity and accuracy, and low sample quantity consumption, this method is suitable for the determination of multiveterinary drug residues in complementary foods for infants and young children. This study provides an effective analysis method for risk monitoring and troubleshooting of complementary foods for infants and young children, which is of great significance in ensuring the healthy growth of the next generation.

Application of LC-MS/MS and UHPLC-Q-Orbitrap methods for determining 54 steroids in illegal dietary supplements and other sample types

RATIONALE

With the development of the Internet and social network services, the public access to or use of illegal products has been increased via on/offline black markets. Steroids refer to the compounds yielding strong treatment effects on some diseases or muscle building, and are classified as the pharmaceutical compounds that are prohibited for personal use without a prescription. The prohibition is made for their potential risk to cause serious adverse effects along with their efficacies.

METHODS

To monitor the distribution of illicit products containing steroids, a simple and reliable analytical method was established and validated, allowing rapid and simultaneous determination of 54 steroids in them. During the screening, LC-Q-Orbitrap/MS was performed first followed by quantitative analysis using LC-MS/MS. For the accurate and reliable analysis, the samples were extracted using QuEChERS to reduce the matrix effect.

RESULTS

After the screening of 617 illegal samples advertised as being effective in alleviating various diseases or improving athletic performance with the established LC-Q-Orbitrap/MS method, the validated LC-MS/MS method was used to perform the quantitative analysis of the detected steroids. Of these, 142 samples were adulterated with steroids, and several samples with two or more steroids were detected. Due to the lack of previous studies on the toxicity of these illicit products, the side effects of consuming them are unpredictable and could be harmful.

CONCLUSIONS

The development of LC-Q-Orbitrap/MS method accompanied by LC-MS/MS could be successfully applied to the inspection of illegal steroid products for public health, enabling the rapid and accurate detection of analytes and incorporation of non-analyte components.

Multiclass and multi-residue screening of mycotoxins, pharmacologically active substances, and pesticides in infant milk formulas through ultra-high-performance liquid chromatography coupled with high-resolution mass spectrometry analysis

Infant milk formulas are designed to substitute human milk when breastfeeding is unavailable. In addition to human milk and milk-derived products, these formulas can be a vehicle of contaminants. In this work, a multiclass method based on the QuEChERS (quick, easy, cheap, effective, rugged, and safe) approach was developed for the simultaneous determination of contaminants (n = 45), including mycotoxins and veterinary drug residues, occurring in infant milk formulas. By using an ultra-high-performance liquid chromatography quadrupole-Orbitrap coupled with high-resolution mass spectrometry analysis (UHPLC-Q-Orbitrap HRMS; Thermo Fisher Scientific), further retrospective analysis of 337 contaminants, including pesticides, was achieved. The method was validated in accordance with European regulations and applied for the analysis of 54 infant milk samples. Risk assessment was also performed. Dexamethasone was detected in 16.6% of samples (range: 0.905-1.131 ng/mL), and procaine benzyl penicillin in 1 sample at a concentration of 0.295 ng/mL. Zearalenone was found in 55.5% of samples (range: 0.133-0.638 ng/mL) and α-zearalenol in 16.6% of samples (range: 1.534-10.408 ng/mL). Up to 49 pesticides, 11 veterinary drug residues, and 5 mycotoxins were tentatively identified via retrospective analysis based on the mass spectral library. These findings highlight the necessity of careful evaluation of contaminants in infant formulas, considering that they are intended for a vulnerable part of the population.

A new LC-MS/MS method for multiple residues/contaminants in bovine meat

A multi-class and multi-residue/contaminant method for the determination of veterinary drug and pesticide residues and mycotoxins in bovine meat has been developed and validated. The veterinary drug residues/contaminants included antimicrobials, anabolic hormones, lactones, β-agonists, mycotoxins, and pesticides. Isotopic labeled internal standards were included to compensate residual matrix effects. The calibrators used in the method demonstrated linearity with the R² > 0.98. The decision limit (CCα) values were in the range from 0.067 to 2103.84 μg/kg, while the range for detection capability (CCβ) was from 0.083 to 2482.13 μg/kg. The limit of detection (LOD) and limit of quantification (LOQ) were in the range from 0.059 to 291.36 μg/kg, and 0.081 to 328.13 μg/kg, respectively. The recovery of analytes ranged from 61.28% to 116.20%. The intra-day coefficient of variation (CV) was from 0.97 to 25.93% and the inter-day CV was 2.30-34.04%. The method has been used for the determination of 49 residues/contaminants in bovine meat. Application of the method in routine analysis in bovine samples, revealed in limited samples the presences of enrofloxacin, oxytetracycline and sulfadiazine at the concentration of 35.22 µg/kg, 27.35 µg/kg, and 36.20 µg/kg, respectively.

Recent Applications of Nano-Liquid Chromatography in Food Safety and Environmental Monitoring: A Review

In recent years, a trend toward instrument miniaturization has led to the development of new and sophisticated analytical systems, such as nano-liquid chromatography (nano-LC), which has enabled improvements of sensitivity, as well as chromatographic resolution. The growing interest in nano-LC methodology has resulted in a variety of innovative and promising applications. In this article, we review the applications of nano-LC separation methods coupled with mass spectrometry in the analysis of food and environmental samples. An assessment of sample preparation methods and analytical performance are provided, along with comparison to other, more established analytical techniques. Three main groups of compounds that are crucial for food safety assessment are considered in this review: pharmaceuticals (including antibiotics), pesticides, and mycotoxins. Recent practical applications of the nano-LC method in the determination of these compounds are discussed. Furthermore, we also focus on methods for the determination of various environmental contaminants using nano-LC methods. Future perspectives for the development of nano-LC methods are discussed.

Exploring miniaturized sample preparation approaches combined with LC-QToF-MS for the analysis of sulfonamide antibiotic residues in meat- and/or egg-based baby foods

Miniaturized and simplified sample preparation methods with reduced consumption of chemicals and non-halogenated solvents are presented for the determination of 12 sulfonamides in baby foods. Hydrophilic interaction liquid chromatography coupled to quadrupole time-of-flight mass spectrometry was used for the identification and quantification of the compounds based on the acquisition of full spectrum at high resolution with accurate mass for precursor and its fragment ions. Three miniaturized protocols based on QuEChERS, salting-out assisted liquid-liquid extraction or low-temperature cleanup were evaluated regarding the extraction efficiency and removal capability of matrix co-extractives. All approaches achieved satisfactory recoveries (70.0-120.0%); however, the miniaturized QuEChERS distinguished by lower co-extractives content in the final extract providing lower matrix effects. Thus, the performance characteristics of the miniaturized QuEChERS were established using different matrices: beef-, egg yolk- and vegetable-based baby food or chicken- and vegetable-based baby food, in compliance with the Codex Alimentarius Commission guidelines. The target compounds were investigated in 30 commercial baby foods.

Suitability of High-Resolution Mass Spectrometry for Routine Analysis of Small Molecules in Food, Feed and Water for Safety and Authenticity Purposes: A Review

During the last decade, food, feed and environmental analysis using high-resolution mass spectrometry became increasingly popular. Recent accessibility and technological improvements of this system make it a potential tool for routine laboratory work. However, this kind of instrument is still often considered a research tool. The wide range of potential contaminants and residues that must be monitored, including pesticides, veterinary drugs and natural toxins, is steadily increasing. Thanks to full-scan analysis and the theoretically unlimited number of compounds that can be screened in a single analysis, high-resolution mass spectrometry is particularly well-suited for food, feed and water analysis. This review aims, through a series of relevant selected studies and developed methods dedicated to the different classes of contaminants and residues, to demonstrate that high-resolution mass spectrometry can reach detection levels in compliance with current legislation and is a versatile and appropriate tool for routine testing.

[Rapid screening and confirmation of 415 pesticide residues in red cabbages by liquid chromatography-quadrupole-time of flight-mass spectrometry]

An analytical method for the simultaneous rapid screening and accurate confirmation of 415 pesticide residues in red cabbages was established using liquid chromatography-quadrupole-time of flight-mass spectrometry (LC-QTOF/MS) with single acquisition. In the established method, the pesticides in red cabbage were extracted using acetonitrile-acetic acid (99∶1, v/v) and salted-out using anhydrous magnesium sulfate and sodium chloride. The resultant solution was then cleaned-up by automatic solid phase extraction using a Carbon/NH2 cartridge. The SPE cartridge was activated with 4 mL acetonitrile-toluene (3∶1, v/v) and the effluents were discarded. The resultant solution was transferred to the Carbon/NH2 cartridge, using 3×2 mL acetonitrile-toluene (3∶1, v/v) to wash the test sample concentrate bottle, and waited until the surface of the test sample concentrate liquid reached the top layer of anhydrous Na2SO4 before transferring the washing liquid to the cartridge. A 30-mL reservoir was attached to the upper part of the SPE cartridge and 25 mL acetonitrile-toluene (3∶1, v/v) was used to wash the SPE cartridge again. The eluent was evaporated in the glass tube in a water bath at 37 ℃ and shaking speed 150 r/min to reduce the volume to 0.5 mL. Nitrogen was used to dry the concentrates, and the residues were dissolved in 1.0 mL acetonitrile-water (3∶2, v/v), homogenized by ultrasonication, and passed through 0.22-μm filtering membrane before determination. The dissolved sample solution was loaded onto a ZORBAX SB-C18 column (100 mm×2.1 mm, 3.5 μm) and separated under gradient elution using 0.1% (v/v) formic acid aqueous solution containing 5 mmol/L ammonium acetate and acetonitrile as the binary mobile phase. The eluent from the column was further detected by QTOF/MS under electrospray positive ionization in the MS/MS scanning mode. A matrix-matched external calibration method was used for quantitation. By optimizing the different parameters under Auto MS/MS and All Ions MS/MS acquisition modes, the optimal conditions for All Ions MS/MS under each acquisition mode were obtained, which were then compared for selection of a better mode. The results demonstrated that the developed method can be used to accurately screen and quantify all 415 pesticides in red cabbage. The linear regression correlation coefficients (r2) for the 415 pesticides were all greater than 0.990 in the corresponding linear concentration range. In addition, the screening detection limits (SDL) of 411 pesticides were no more than 5 μg/kg, and the limits of quantification (LOQs) of 413 pesticides were no more than 10 μg/kg. At the spiked levels of LOQ, two-fold LOQ, and 10-fold LOQ, the recoveries were in the ranges of 65.7%-118.4%, 72.0%-118.8% and 70.2%-111.2%, with relative standard deviations (RSDs) in the ranges of 0.9%-19.7%, 0.2%-19.9% and 0.6%-19.9%, respectively. The method was applied to detect pesticide residues in the red cabbage samples provided by the 2019 European proficiency test project for unknown pesticide screening (EUPT-SM-11) and accurate quantitation (EUPT-FV-21). For EUPT-SM-11, all the spiked and incurred pesticides in red cabbage were qualified accurately, without false positives or false negatives. This is completely consistent with the final results published by the EU official. For EUPT-FV-21, there were 19 non-volatile pesticides that can be detected by LC-MS, which were then accurately quantitated with the corresponding pesticide standard. The results demonstrate that the proposed method is accurate and reliable. It is also rapid and time-saving, and can be used for high-throughput screening and quantitative determination of pesticide residues in cabbage. It can also be extended to other fruits and vegetable matrices.

Wide-scope screening for pharmaceutically active substances in a leafy vegetable cultivated under biogas slurry irrigation

The use of livestock waste for the production of biogas and the application of biogas slurry to agricultural soil can resolve livestock waste problems and reduce synthetic fertiliser use. However, the migration of veterinary drugs to land and crops resulting from biogas slurry irrigation is a potential food safety concern. This study employed an ultra-performance liquid chromatography coupled with quadrupole-time of flight high-resolution mass spectrometry system for wide-scope suspect screening of pharmaceutically active substances on crop cultivated under biogas slurry irrigation. Briefly, a total of 22 pak choi samples were obtained from a greenhouse farmed in tropical south Taiwan between March 2019 and March 2020. Molecular spectra and fragmented ions (between m/z 70 and 1100) were acquired. Ion features were searched and matched with a library consisting of 1068 compounds. The matrixes in the crop production environment including soil, livestock wastewater, biogas slurry, and groundwater were included in this study to elucidate potential sources of the pharmaceutically active substances. Results demonstrated 23 suspects were matched with high mass accuracy (mass error within ±5.0 ppm) in pak choi. The detection of both bufexamac and nandrolone were confirmed using standards, where a new system of identification points was applied. Nandrolone was detected throughout the pak choi samples as well as livestock wastewater. Tetracycline, macrolide, and sulfonamide antibiotics were presented in biogas slurry and soil but not pak choi. This is the first study to reveal the presence of multiclass pharmaceutically active substances in a crop supplied as food. Such findings suggest that anabolics and antibiotics should be closely monitored in the corps irrigated by biogas slurry in future.

Facile preparation of magnetic covalent organic framework-metal organic framework composite materials as effective adsorbents for the extraction and determination of sedatives by high-performance liquid chromatography/tandem mass spectrometry in meat samples

RATIONALE

Sedatives, which are prone to cause residues in animals, have been abused in modern animal husbandry. Long-term consumption of contaminated meat products would be unfavorable to the human nervous system. Taking into account public health and food safety, it was essential to develop an effective method for the enrichment and detection of sedatives in meat.

METHODS

Fe₃ O₄ @TbBd@ZIF-8 composites were synthesized by using Fe₃ O₄ nanoparticles as a magnetic core and 1,3,5-triformylbenzene (Tb) and benzidine (Bd) as two building blocks to form Fe₃ O₄ @TbBd. Furthermore, the zeolitic imidazolate framework-8 (ZIF-8) was modified on the surface of the Fe₃ O₄ @TbBd. In addition, Fe₃ O₄ @TbBd@ZIF-8 was used as a magnetic solid-phase extraction (MSPE) adsorbent of typical animal sedatives in pork samples. Mass spectrometry analysis was conducted by electrospray ionization triple-quadrupole mass spectrometry in positive-ion multiple reaction monitoring mode.

RESULTS

By combining the optimized MSPE approach with high-performance liquid chromatography/tandem mass spectrometry (HPLC/MS/MS), an accurate and sensitive method for the determination of sedatives was developed. The method exhibited good linearity in the range of 0.03-70 μg/kg with the correlation coefficient (R² ) ranging from 0.9982 to 0.9999, high sensitivity with limits of detection (LODs) ranging from 0.04 to 0.2 μg/kg, and high precision with relative standard deviation (RSD) less than 5.5%. The adsorption behaviors of Fe₃ O₄ @TbBd@ZIF-8 towards sedatives were more suitably described by a pseudo-second-order kinetic and Freundlich isotherm model.

CONCLUSIONS

The proposed MSPE-HPLC/MS/MS method was successfully applied to the determination of sedatives in real samples and showed excellent applicability. Several sedatives were detected in the selected meat samples. The developed method was shown to be facile, sensitive and accurate for sedative detection and also showed great prospects for determination of sedatives from other complex samples.

Multiclass and multiresidue screening of veterinary drugs and pesticides in infant formula using Quadrupole-Orbitrap MS with PRM scan mode

A multiclass and multiresidue method for screening veterinary drugs and pesticides in infant formula was developed and validated using ultrahigh-performance liquid chromatography coupled to Quadrupole-Orbitrap high-resolution mass spectrometry (UHPLC-HRMS). A total of 49 veterinary drugs and pesticides investigated belong to 11 classes including antivirals, anticoccidials, macrolides, pyrethroids, insecticides, sulfonamides, beta-agonists, sedatives, thyreostats, nonsteroidal anti-inflammatory drugs, and other pharmacologically active substances. A generic sample preparation and highly selective acquisition mode of parallel reaction monitoring (PRM) were deliberately incorporated to perform efficient screening analysis. As a result, the screening target concentrations of the analytes varied from 1 to 500 μg/kg with ≤5% of false compliant rate as specified in Decision 2002/657/EC for screening analysis. The average recoveries ranged from 40.7 to 124.9% as well as the relative standard deviations from 4.2 to 26.6%, respectively. The matrix effects and interferences were effectively controlled by integrated application of dispersive solid phase extraction, PRM scan mode, and matrix-matched standard calibration. The proposed method will be helpful to provide applicable strategy for screening residues in infant formula with surveillance purpose.

A multi-class multi-residue method for the analysis of polyether ionophores, tetracyclines and sulfonamides in multi-matrices of animal and aquaculture fish tissues by ultra-high performance liquid chromatography tandem mass spectrometry

An ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS) based multiclass multi-residue method for the simultaneous analysis of 5 polyether ionophores, 4 tetracycline and 10 sulfonamides in animal and aquaculture fish tissues was developed and validated. Sample extraction and clean-up were based on a modified QuEChERS method. The method was validated using an in-house validation based on performance characteristics modified from Commission Decision 2002/657/EC. Both matrix effect and uncertainties associated with sample preparation and instrumental analysis were minimised by the use of matrix-matched calibrations. Recoveries of analytes were generally satisfactory and typically fell between 80% and 113%. The repeatability and intermediate reproducibility measured as relative standard deviations were in most cases less than 15% (n = 63). The decision limit (CCα) and detection capability (CCβ) ranged from 110.7 to 125.8 and 121.5 to 151.7 µg kg^-1 for tetracyclines, 113.4 to 118.3 and 116.8 to 126.5 µg kg^-1 for sulfonamides and 50.8 to 52.4 and 51.5 to 55.6 µg kg^-1 for polyether ionophores, respectively. The method displayed its fitness for purpose through satisfactory results obtained in international proficiency testing schemes. The method was applied to animal and aquaculture fish tissues obtained from different sources in South Africa. Polyether ionophores were predominantly detected in samples in the range 4.26-290.10 µg/kg. Oxytetracycline was found in one porcine liver sample; however, none of the targeted analytes were present above the detection limit in the aquaculture samples.

A high-throughput metabolomics approach for the comprehensive differentiation of four Pulsatilla Adans herbs combined with a nontargeted bidirectional screen for rapid identification of triterpenoid saponins

Pulsatilla Adans (PSA) herbs (Ranunculaceae) have been widely used in traditional medicine in China and other countries. However, the authentication and quality control of PSA herbs have always been a challenging task due to their similar morphological characteristics and the diversity of the multiple components that exist in the complicated matrix. Herein, a novel integrated strategy combining UHPLC/Q-Orbitrap-MS techniques with chemometrics analysis is proposed for the discrimination of PSA materials. We developed a comprehensive method integrating a nontargeted bidirectionally screened (NTBDS) MS data set and a targeted extraction peak area analysis for the characterization of triterpenoid saponins of PSA from different species. After that, partial least-squares discriminant analysis (PLS-DA) was performed on the obtained MS data set and the parameter variable importance for the projection (VIP) value and P value were employed to screen the valuable MS features to discriminate PSA from different species. In addition, the receiver operating characteristic (ROC) curve is used to verify the reliability of MS features. Finally, heatmap visualization was employed to clarify the distribution of the identified triterpenoid saponins, and four medicinal species of PSA were successfully differentiated. Additionally, 34 constituents were reported in PSAs for the first time, 81 triterpenoid saponins were identified as differential components, and 12 chemical ingredients were characterized as potential chemical markers to differentiate the four officinal PSA herbs. This is the first time that the differences in different PSA herbs have been observed systematically at the chemical level. The results suggested that using the identified characteristic components as chemical markers to identify different PSA herbs was effective and viable. This method provides promising perspectives in the analysis and identification of the ingredients of Chinese herbal medicines, and the identification of similar herbs from the same species.

Screening of multiclass pesticide residues in honey by SPE-GC/MSD: a pilot study

Analytical method for the monitoring of residues of multiclass pesticides (variable chemical structure and chromatographic behavior) in honey has been optimized and in-house validated in the present study. Chemical confirmation of 35 selected pesticides (in-hive-treated pesticides and pesticides applied for agricultural practices in vicinity of apiaries) has been successfully achieved with the acetonitrile extraction/partitioning and cleanup by modified US EPA solid-phase extraction (SPE) protocol following analysis on the GC/MS DRS Pesticide Screener. The applied extraction procedure has given acceptable recoveries with an associated precision (RSD) for selected pesticides within the range as suggested by SANTE at MQL of 10 μg kg^-1. Potential matrix effect for selected analytes was calculated by using honey from five different floral sources. The optimized method was used to determine levels of pesticide residues in honey samples randomly collected from 26 different apiaries in Pakistan. Residues of nine selected pesticide (dichlorvos, mevinphos, ethalfluralin, trifluralin, lindane, chlorpyrifos-methyl, dieldrin, profenofos, 4,4-DDE) were frequently detected in the ranges of 3-48.8 μg kg^-1 in 26.9% of analyzed samples (n = 26) and 15.3% of the studied samples exceeded maximum residue limits (MRLs). In-hive-treated acaricides, i.e., coumaphos, tau-fluvalinate, and malathion, were not detected in any of the analyzed honey samples.

Screening of drugs and homeopathic products from Atropa belladonna seed extracts: Tropane alkaloids determination and untargeted analysis

Homeopathic products are still a controversial issue in modern medicine, understood as complementary or alternative medicine (CAM). In this particular case, homeopathic products prepared from Atropa belladonna extracts may present specific problems due to the effects derived from its components. This article applies a simple, rapid, reliable method to the analysis of different homeopathic products obtained from Atropa belladonna; drugs containing high concentration of plant extracts; and Atropa belladonna seeds. The method was based on a simple solid-phase preconcentration method followed by ultra-high pressure liquid chromatography (UHPLC) coupled to high resolution mass spectrometry using Exactive-Orbitrap as an analyser. An in-house database was set and atropine and scopolamine were the compounds detected at highest concentrations in homeopathic products from Atropa belladonna extracts (4.57 and 2.56 μg/kg, respectively), in Belladonna ointment (4007 and 1139 μg/kg, respectively) and Belladonna seeds (338 and 32.1 mg/kg, respectively). Other tropane alkaloids such as tropine, apoatropine, aposcopolamine, tropinone, homatropine, and anisodamine were detected at lower concentrations (0.04-1.36 μg/kg). When untargeted analysis was performed, other tropane alkaloids were identified in the tested samples, such as ecgonine (0.003 μg/kg), benzoylecgonine (0.56 μg/kg), calystegines A (19.6 μg/kg), B (33.1 μg/kg), and C (1.01 μg/kg). Finally other compounds present in the homeopathic products, such as sugars (fructose, glucose, and lactose) or amino acids (valine, ornithine, leucine, and phenylalanine), were identified.

Screening of veterinary drug residues in food by LC-MS/MS. Background and challenges

Regulatory agencies and government authorities have established maximum residue limits (MRL) in various food matrices of animal origin for supporting governments and food operators in the monitoring of veterinary drug residues in the food chain, and ultimately in the consumer's plate. Today, about 200 veterinary drug residues from several families, mainly with antibiotic, antiparasitic or antiinflammatory activities, are regulated in a variety of food matrices such as milk, meat or egg. This article provides a review of the regulatory framework in milk and muscle including data from Codex Alimentarius, Europe, the U.S.A., Canada and China for about 220 veterinary drugs. The article also provides a comprehensive overview of the challenge for food control, and emphasizes the pivotal role of liquid chromatography-mass spectrometry (LC-MS), either in tandem with quadrupoles (LC-MS/MS) or high resolution MS (LC-HRMS), for ensuring an adequate consumer protection combined with an affordable cost. The capability of a streamlined LC-MS/MS platform for screening 152 veterinary drug residues in a broad range of raw materials and finished products is highlighted in a production line perspective. The rationale for a suite of four methods intended to achieve appropriate performance in terms of scope and sensitivity is presented. Overall, the platform encompasses one stream for the determination of 105 compounds in a run (based on acidic QuEChERS-like), plus two streams for 23 β-lactams (alkaline QuEChERS-like) and 10 tetracyclines (low-temperature partitioning), respectively, and a dedicated stream for 14 aminoglycosides (molecularly-imprinted polymer).

Development of Multiple Heart-Cutting Two-Dimensional Liquid Chromatography Coupled to Quadrupole-Orbitrap High Resolution Mass Spectrometry for Simultaneous Determination of Aflatoxin B1, B2, G1, G2, and Ochratoxin A in Snus, a Smokeless Tobacco Product

The combination of multiple heart-cutting two-dimensional liquid chromatography (MHC-LC/LC) and quadrupole-orbitrap high-resolution mass spectrometry (HRMS) for simultaneous determination of the aflatoxins and ochratoxin A in snus is presented in this work. A C18 capillary column was used as the first dimension (1D) to isolate the aflatoxins and ochratoxin A from the complex matrices; then, a 2-position/10-port high-pressure valve equipped with two 60 μL loops was employed to transfer the heart-cuts of 1D-LC into a pentafluorophenyl (PFP) column for the second dimension (2D) separation. With the better separation of the MHC-LC/LC system, the sensitivity of the method was improved, which is essential for the trace mycotoxins analysis. Furthermore, HRMS performed in parallel reaction monitoring mode was employed to eliminate the interferences, and the sample pretreatment procedure was simplified. A new approach utilizing ethyl acetate with 1% formic acid/water solution was adopted to extract aflatoxins and ochratoxin A in snus, which provided parallel recoveries for aflatoxins and ochratoxin A with higher responses in comparison with the QuEChERS method. A dynamic range between 0.2 and 20 μg/kg was achieved with LOQs of 0.05 μg/kg for aflatoxin B₁, 0.1 μg/kg for aflatoxin B₂, G₁, G₂, and 1.0 μg/kg for ochratoxin A in dry mass of product. The results revealed that the established method exhibited good repeatability and recovery and could be used as a rapid and reliable approach for routine analysis of aflatoxins and ochratoxin A in snus.

LC-MS/MS determination of pesticide residues in fruits and vegetables

The aim of the research is to evaluate pesticide residue contamination of fresh and frozen fruits and vegetables, agricultural raw material, purchased from Polish farmers for production of frozen fruits and vegetables, and the estimation of the multiresidue method effectiveness expressed as the proportion of pesticides detected in food samples to the total number of pesticides analyzed by multiresidue methods. A total of 144 samples (of black currants, red currants, raspberries, cherries, strawberries, blackberries, cauliflowers and broccoli) were analyzed using LC-MS/MS method for the determination of 60 pesticides. QuEChERS extraction, matrix-matched calibration and dynamic multiple reaction monitoring method were used. Residues of 15 compounds, mainly fungicides and insecticides, were detected in 46 samples. The percentage of samples with residues above the maximum residue levels (MRL) was 15%, whereas samples with residues below MRL were 17%. A total of 13 samples contained more than one pesticide residue. Pesticide residues were detected most often in samples of black currants (50%), broccoli (36.4%), raspberries (29%) and red currants (21.8%). The most frequently detected pesticides were carbendazim and acetamiprid. The proportion of pesticides detected during our study to the total number of analyzed pesticides amounted to 25%. It was compared to literature findings. For three fourth of multiresidue methods, the proportion was below 50% for methods developed for the analysis of less than 100 pesticides, and below 30% for methods developed for the analysis of more than 100 pesticides. It appears that a lot of efforts and means is lost on pesticides never or rarely detected in examined samples. The workload and cost effectiveness of the development and application of multiresidue methods along with the range of pesticides covered by the method should be carefully and thoroughly considered anytime when a new method or workflow is developed. Including non-targeted screenings in pesticide residue control seems to be an alternative worth considering.

Veterinary drugs residues: a review of the latest analytical research on sample preparation and LC-MS based methods

The world population is increasing and there is a growing demand for food, leading to intensification of farming methods and a requirement for more coadjuvants. Potential high profits sometimes lead to fraudulent use of drugs and pesticides. Veterinary drugs in particular can pose a real risk to human health if their residues are allowed to enter the food chain. Parent drugs and their metabolites can occur in foodstuffs individually or as multicomponent mixtures with enhanced adverse effects. In order to protect consumer safety, the European Union has established lists of forbidden substances, maximum residue limits for authorised drugs and precise criteria for confirmation analyses and interpretation of the results. Due to their nature and potential danger, the 'best available technique' should always be applied. Following this principle, this review examines the procedures and techniques applied to monitoring pharmaceutical products of major concern (e.g. anthelmintics, NSAIDs, corticosteroids, coccidiostats) in foods of animal origin, discussing advances over the past five years and future trends in the field of food safety. Our goal was both to focus attention on this important topic and to provide a selection of the most relevant recent papers on drug residues in foodstuffs.

Determination of rodenticides and related metabolites in rabbit liver and biological matrices by liquid chromatography coupled to Orbitrap high resolution mass spectrometry

An analytical method based on ultra-high performance liquid chromatography (UHPLC) coupled to Orbitrap high resolution mass spectrometry was developed for the determination of rodenticides (bromadiolone, brodifacoum, difenacoum, chlorophacinone, diphacinone, coumachlor and warfarin) in liver matrix. Different extraction conditions were tested, obtaining the best results when the "dilute and shoot" method (acidified acetonitrile as extraction solvent) and a clean-up step with primary secondary amine (PSA) were used. The optimized method was validated, obtaining recoveries ranging from 60 to 120%. Repeatability and reproducibility were evaluated obtaining values lower than 20%, except for brodifacoum at 10μg/kg. Limits of quantification (LOQs) ranged from 0.1 to 0.5μg/kg, except for brodifacoum, which was 100μg/kg. Six liver samples were analyzed and diphacinone and chlorophacinone were detected in three samples at concentrations ranging from 4μg/kg to 13μg/kg. Moreover a retrospective screening of rodenticide metabolites in those samples and in animal forensic samples was developed based on Orbitrap capabilities. Brodifacoum was detected in three samples, and warfarin alcohol, which is a metabolite of warfarin, was also detected in one sample.

A Quantitative Structure Activity Relationship for acute oral toxicity of pesticides on rats: Validation, domain of application and prediction

Quantitative Structure Activity Relationship (QSAR) models are expected to play an important role in the risk assessment of chemicals on humans and the environment. In this study, we developed a validated QSAR model to predict acute oral toxicity of 329 pesticides to rats because a few QSAR models have been devoted to predict the Lethal Dose 50 (LD50) of pesticides on rats. This QSAR model is based on 17 molecular descriptors, and is robust, externally predictive and characterized by a good applicability domain. The best results were obtained with a 17/9/1 Artificial Neural Network model trained with the Quasi Newton back propagation (BFGS) algorithm. The prediction accuracy for the external validation set was estimated by the Q(2)ext and the root mean square error (RMS) which are equal to 0.948 and 0.201, respectively. 98.6% of external validation set is correctly predicted and the present model proved to be superior to models previously published. Accordingly, the model developed in this study provides excellent predictions and can be used to predict the acute oral toxicity of pesticides, particularly for those that have not been tested as well as new pesticides.