Application and evaluation of a high-resolution mass spectrometry screening method for veterinary drug residues in incurred fish and imported aquaculture samples

Silybin protected from avermectin-induced carp (Cyprinus carpio) nephrotoxicity by regulating PPAR-γ-involved inflammation, oxidative stress, ferroptosis and autophagy

Avermectin, a widely used deworming drug, poses a significant threat to fisheries. Silybin is recognized for its antioxidant and anti-inflammatory properties. The kidney, being crucial for fish survival, plays a vital role in maintaining ion balance, nitrogen metabolism, and hormone regulation. While residual avermectin in water could pose a risk to carp (Cyprinus carpio), it remains unclear whether silybin can alleviate the renal tissue toxicity induced by avermectin in this species. In current study, we developed a model of long-term exposure of carp to avermectin to investigate the potential protective effect of silybin against avermectin-induced nephrotoxicity. The results indicated that avermectin induced renal inflammation, oxidative stress, ferroptosis, and autophagy in carp. Silybin suppressed the mRNA transcript levels of pro-inflammatory factors, increased catalase (CAT) activity, reduced glutathione (GSH) activity, diminished reactive oxygen species (ROS) accumulation in renal tissues, and promoted the activation of the Nrf2-Keap1 signaling pathway. Furthermore, the transcript levels of ferroptosis-associated proteins, including gpx4 and slc7a11, were significantly reduced, while those of cox2, ftl, and ncoa4 were elevated. The transcript levels of autophagy-related genes, including p62 and atg5, were also regulated. Network pharmacological analysis revealed that silybin inhibited ROS accumulation and mitigated avermectin-induced renal inflammation, oxidative stress, ferroptosis, and autophagy in carp through the involvement of PPAR-γ. Silybin exerted its anti-inflammatory effect through the NF-κB pathway and antioxidant effect through the Nrf2-Keap1 pathway, induced renal cell iron efflux through the SLC7A11/GSH/GPX4, and suppressed autophagy initiation via the PI3K/AKT pathway. This study provides evidence of the protective effect of silybin against avermectin-induced nephrotoxicity in carp, highlighting its potential as a therapeutic agent to alleviate the adverse effects of avermectin exposure in fish.

Analysis of chemical contaminants in fish using high resolution mass spectrometry - A review

High resolution mass spectrometry (HRMS) has become an important tool in environmental and food safety analysis. This review highlights how HRMS has been used to analyze chemical contaminants in fish. Measuring and documenting chemical contaminants in fish serves not only as an indicator of environmental conditions but can also monitor the health of these animals and help protect an important source of human food. The incidence and significance of contaminants including veterinary drugs, human drugs and personal care products, pesticides, persistent organic pollutants, per- and poly fluorinated substances, and marine toxins will be reviewed. The advantage of HRMS over traditional MS is its ability to expand the number of compounds that can be detected and identified. This is true whether HRMS is used for targeted analytes, or more broadly for suspect screening and nontargeted analyses. The classes of compounds, types of fish or seafood, options for data acquisition and analysis, and reports of unexpected findings from recent HMRS methods for chemical contaminants in fish are summarized.

Simultaneous Screening of 172 Veterinary Drugs by Modified QuEChERS-LC-MS/MS in TCM Galli Gigerii Endothelium Corneum

An analytical method was developed for the screening of 172 veterinary drugs in traditional Chinese medicine Galli Gigerii Endothelium Corneum by high-performance liquid chromatography tandem mass spectrometry. The samples were pretreated by a modified QuEChERS method. A Zorbax Eclipse plus C18 column (1.8 μm, 3.0 × 150 mm2, Agilent) was used for the separation of analytes by gradient elution. All analytes were detected by electrospray ionization mass spectrometry with multiple reaction monitoring mode. Good linearity with R ≥ 0.99 was exhibited for all analytes within the respective range. The recoveries of all monitored analytes ranged from 55.4 to 127.6% at three spiked levels (limit of quantitation-LOQ, 2-fold LOQ, 10-fold LOQ), with relative standard deviations <17.8%. The estimated LOQ levels were 0.2-20 μg/kg. The application of this method provides a reference for the safety control of traditional Chinese medicines.

Suspect screening for chemical residues in aquacultured shrimp and fish using liquid chromatography-high resolution mass spectrometry: comparison of data evaluation approaches

High-resolution mass spectrometry (HRMS) has become an important tool for monitoring chemical residues in food, but the time and effort required to evaluate the large amount of data generated by HRMS can be a limiting factor in the widespread application of this tool. Suspect screening, i.e., searching HRMS data against large compound databases or mass lists, represents a practical compromise between using HRMS data to only look for target compounds and performing full non-target analysis. Several different approaches for suspect screening using HRMS data were tested using data from shrimp and eel spiked with veterinary drugs and pesticides as well as from imported aquaculture samples. Most of the analytes (>70%) in the spiked samples were detected and identified by searching against compound databases. To query larger databases and on-line resources such as mzCloud, it was necessary to use software capable of differential analysis and selective filtering, such as Compound Discoverer. Using selective filtering, the number of compounds detected in fish sample extracts could be reduced from tens of thousands to a few hundred by subtracting method blanks and comparing to matrix blank extracts. This smaller list of potential compounds could be further evaluated and compared to available databases and libraries. Analysis of imported aquaculture samples resulted in detection of unexpected contaminants including the dewormer levamisole, the insecticide buprofezin, and potentially the plant alkaloid ricinine.

Recent Advances in the Determination of Veterinary Drug Residues in Food

The presence of drug residues in food products has become a growing concern because of the adverse health risks and regulatory implications. Drug residues in food refer to the presence of pharmaceutical compounds or their metabolites in products such as meat, fish, eggs, poultry and ready-to-eat foods, which are intended for human consumption. These residues can come from the use of drugs in the field of veterinary medicine, such as antibiotics, antiparasitic agents, growth promoters and other veterinary drugs given to livestock and aquaculture with the aim of providing them as prophylaxis, therapy and for promoting growth. Various analytical techniques are used for this purpose to control the maximum residue limit. Compliance with the maximum residue limit is very important for food manufacturers according to the Food and Drug Administration (FDA) or European Union (EU) regulations. Effective monitoring and control of drug residues in food requires continuous advances in analytical techniques. Few studies have been reviewed on sample extraction and preparation techniques as well as challenges and future directions for the determination of veterinary drug residues in food. This current review focuses on the overview of regulations, classifications and types of food, as well as the latest analytical methods that have been used in recent years (2020-2023) for the determination of drug residues in food so that appropriate methods and accurate results can be used. The results show that chromatography is still a widely used technique for the determination of drug residue in food. Other approaches have been developed including immunoassay, biosensors, electrophoresis and molecular-based methods. This review provides a new development method that has been used to control veterinary drug residue limit in food.

Molecular mechanism of kidney damage caused by abamectin in carp: Oxidative stress, inflammation, mitochondrial damage, and apoptosis

Indiscriminate use of pesticides not only leads to environmental pollution problems, but also causes poisoning of non-target organisms. Abamectin (ABM), a widely used insecticide worldwide, is of wide concern due to its persistence in the environment and its high toxicity to fish. The kidney, as a key organ for detoxification, is more susceptible to the effects of ABM. Unfortunately, few studies investigated the mechanisms behind this connection. In this study, carp was used as an indicator organism for toxicological studies to investigate renal damage caused by ABM residues in carp. In this work, carp were exposed to ABM (0, 3.005, and 12.02 μg/L) for 4 d and the nephrotoxicity was assessed. Histopathological findings revealed that ABM exposure induced kidney damage in carp, as well as an increase Creatinine and BUN levels. Meanwhile, ABM as a reactive oxygen species (ROS) stimulator, boosted ROS bursts and lowered antioxidant enzyme activity while activating the body's antioxidant system, the Nrf2-Keap1 signaling pathway. The accumulation of ROS can also lead to the imbalance of the body's oxidation system, leading to oxidative stress. At the same time, NF-κB signaling pathway associated with inflammation was activated, which regulated expression levels of inflammatory cytokines (TNF-α, IL-6, IL-1β, and iNOS increased, while IL-10 and TGF-β1 decreased). In addition, ABM exposure caused structural damage to kidney mitochondria of carp, resulting in decreased mitochondrial membrane potential and ATP production capacity, and mediated apoptosis through endogenous pathways Bax/Bcl-2/Caspase-9/Caspase-3. In conclusion, ABM caused kidney damage in carp by inducing oxidative stress, inflammation, and apoptosis through mitochondrial pathway. These findings will be useful for future research into molecular mechanisms of ABM-induced nephrotoxicity in aquatic organisms.

Multiresidues Multiclass Analytical Methods for Determination of Antibiotics in Animal Origin Food: A Critical Analysis

Veterinary drugs are widely used to prevent and treat diseases. The European Union has forbidden the use of antibiotics as growth promoters since 2006. Its abusive use leads to the presence of antibiotic residues (AR) in foods of animal origin which is associated with antibiotic resistance. The monitoring of AR in food intended for human consumption is of utmost importance to assure Food Safety. A systematic bibliographic review was carried out on the analytical methodologies, published in 2013, for the determination of AR in foods of animal origin. The food processing effect in the AR detected in animal products is also addressed. However, there is a preference for multiresidues multiclass methods, i.e., methodologies that allow determining simultaneously different classes of antibiotics, which is still a challenge for researchers. The wide diversity of physico-chemical properties of these drugs is an obstacle to achieving excellent analytical performance for a vast number of molecules analyzed concurrently. New techniques in sample preparation continue to be developed in order to obtain a compromise between good recoveries and extracts without interferences (clean extracts). The most widely used analytical methodology for the determination of AR is liquid chromatography coupled with mass spectrometry. However, the current trend is focused on the use of powerful high-resolution MS detectors such as Time of Flight and Orbitrap with modern chromatographic systems. Cooking time and temperature control are the key processing conditions influencing the reduction of AR in foods.

Heterologous-coating antigen enhancing the sensitivity of enzyme-linked immunosorbent assay for detection of mebendazole residues

The heterologous strategy could improve the sensitivity of competitive enzyme-linked immunosorbent assay (ELISA) for detection of chemical contaminants in food samples. In this study, the heterologous coating antigen ELISA was developed to evaluate its sensitivity for mebendazole (MBZ). Results showed that the heterologous ELISA had a linear range of (IC₂₀-IC₈₀) 0.34-10.54 ng/mL, an IC₅₀ value of 1.83 ng/mL, and a limit of detection (LOD) of 0.13 ng/mL, in which the sensitivity of ELISA improved 1.7- and 2-fold (IC₅₀ value dropping from 7.41 and 3.65 ng/mL to 4.27 and 1.83 ng/mL) than that of rabbit IgG- and chicken IgY-based homologous ELISA for MBZ, respectively. The heterologous coating antigen ELISA showed negligible cross reactivity (<0.2%) with its structural analogues, including hydroxy-MBZ, albendazole, oxfendazole, fenbendazole, and flubendazole, except the value of 72.6% for amino-MBZ. The average recoveries of MBZ spiked in pork and chicken muscle samples by the assay ranged from 83.7% to 109.8% and agreed well with those of high-performance liquid chromatography. The results suggested that using heterologous coating antigen could distinctly improve the sensitivity of ELISA for routine screening of MBZ residues in food samples.

Metabolism and pharmacokinetics of mebendazole in Japanese pufferfish (Takifugu rubripes)

As a typical and broad-spectrum benzimidazole, mebendazole (MBZ) has long been used in human and veterinary medicine to treat parasitic infestations, and is widely employed in the aquaculture of Japanese pufferfish (Takifugu rubripes). However, there have been no studies examining the pharmacokinetic characteristics of MBZ in Japanese pufferfish. Furthermore, the presence of MBZ and its metabolites in animal-derived raw food represents a notable safety concern. Here, we investigated the metabolism of MBZ using a UPLC-Q-TOF system. Additionally, we evaluated the pharmacokinetics of MBZ and two metabolites, 2-amino-5(6)-benzoylbenzimidazole (MBZ-NH₂) and 5-hydroxymebendazole (MBZ-OH), in Japanese pufferfish following intramuscular injection of 20 mg/kg MBZ. We detected three metabolites of MBZ (M1-M3), among which, 2-amino-5(6)-(a-hydroxybenzyl) benzimidazole (M3) was detected in an aquatic animal for the first time. The plasma dispositions of MBZ, MBZ-NH₂, and MBZ-OH were characterized by low plasma clearance, medium distribution volume, and long terminal half-life. Moreover, these compounds were widely distributed in the muscle, from which they were rapidly cleared. The pharmacokinetics and metabolism of mebendazole in Japanese pufferfish are described for the first time in this study. Our findings provide a basis for the rational application of MBZ in Japanese pufferfish farming and contribute to our understanding of the metabolism of MBZ in cultured fish.

New Evidence of Rubber-Derived Quinones in Water, Air, and Soil

p-Phenylenediamines (PPDs) have been extensively used in the rubber industry and found to be pervasive in various environmental compartments for decades, while their transformation products and associated ecological and human health risks remain largely unknown. Herein, we developed and implemented a mass spectrometry-based platform combined with self-synthesized standards for the investigation of rubber-derived quinones formed from PPD antioxidants. Our results demonstrated that five quinones are ubiquitously present in urban runoff, roadside soils, and air particles. All of the identified sources are closely related to mankind's activities. Among the identified quinones, N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine quinone has been recently found to be highly toxic, causing acute mortality of coho salmon in the Pacific Northwest. Ultrahigh-performance liquid chromatography coupled with triple quadrupole mass spectrometry was then applied for quantification of the five quinones and their corresponding PPD antioxidants. The results revealed interesting distinct distribution and concentration patterns of PPD-derived quinones in different environmental matrices. Daily intake rates of these quinones in a compact city of Hong Kong were estimated to be varied from 1.08 ng/(kg·day) for adults to 7.30 ng/(kg·day) for children, which were higher than the exposure levels of their parent compounds. Considering the prevalence of the use of rubber products, the outcome of this study strongly suggests for additional toxicological studies to investigate potential ecological and human health risks of the newly discovered quinones.

Toxicity of avermectin to Eriocheir sinensis and the isolation of a avermectin-degrading bacterium, Ochrobactrum sp. AVM-2

Avermectin is widely used in the prevention and treatment of parasites diseases in aquaculture. However, the residual avermectin has a serious impact on the growth and quality of aquatic animals including Eriocheir sinensis. This study shows that the LC50 of avermectin to E. sinensis for 24, 48, 72 and 96 h was 21.88, 13.40, 9.11 and 7.10 mg/L, respectively. After avermectin stress, the activities of superoxide dismutase (SOD), catalase (CAT) and phenol oxidase (PO) in the hepatopancreas of E. sinensis increased and reached the peak on the 6th day. The content of malondialdehyde (MDA) accumulated with the increase of exposure time and concentration of avermectin. After 15 days of avermectin exposure, hepatopancreas was damaged seriously. These results indicated that avermectin had toxicity to E. sinensis. In order to solve the pollution problem caused by residual avermectin, a degrading bacterium AVM-2 was separated from the sediment of E. sinensis breeding pond. The strain was confirmed to be Ochrobactrum sp by morphology observation, physiological and biochemical identification and 16 S rDNA sequences analysis. When the pH value was 7, the temperature was 30 ℃, the concentration of substrate was low, the quantity of inoculation was high, Ochrobactrum sp. AVM-2 had better degradation effect on avermectin. When the addition of Ochrobactrum sp. AVM-2 was 2.34 × 108 CFU/L, the residual avermectin in muscle and hepatopancreatine significantly decreased, and the degradation rate was about 66%. In summary, Ochrobactrum sp. AVM-2 could be used to solve the residual problem of avermectin and ensure the food safety of E. sinensis.

Development of a sensitive chicken IgY-based enzyme-linked immunosorbent assay for detection of mebendazole in pork and mutton

Chicken egg yolk IgY has proven to be qualified for analysis of targets in immunoassays. In order to explore the feasibility of chicken IgY-based ELISA for detection of mebendazole (MEB), the chicken IgY against MEB was generated in the laying hens. An enzyme-linked immunosorbent assay (ELISA) based on chicken IgY was developed for detection of MEB with a half-maximum signal inhibition concentration (IC₅₀) of 3.65 ng mL^-1 and a limit of detection of 0.25 ng mL^-1. The assay showed a lower cross reactivity (less than 1%) with other structures analogues (except amino-MEB with the values of 70.7%). The average recoveries of MEB spiked in pork and mutton muscle samples ranged from 93.6% to 106.3% with relative standard deviation less than 8.78% and 10.85% for intra-assay and inter-assay, respectively, and agreed well with those of high-performance liquid chromatography. Our results indicate that generated IgY could be used as a robust reagent for routine screening analysis of small molecular compounds residues in food samples.

Simultaneous determination of pharmaceuticals and metabolites in fish tissue by QuEChERS extraction and UHPLC Q/Orbitrap MS analysis

In recent years, the occurrence, fate, and adverse effects of pharmaceutically active compounds (PhACs) in aquatic organisms have become a noteworthy issue. In the present study, a rapid and sensitive multiresidue analytical method was developed for the determination of 18 parent PhACs and 5 metabolites in sea bream (Sparus aurata), by combining a modified QuEChERS (quick, easy, cheap, effective, rugged and safe) procedure with ultra-high performance liquid chromatography-Orbitrap-mass spectrometry (UHPLC-Orbitrap-MS). The method development involved optimization of extraction solvent, extraction salts, clean-up sorbents, and amount of sample evaluation, while identification on Orbitrap MS was based on accurate mass and further confirmation with MS/MS fragmentation. The developed method was validated, and linearity was higher than 0.99. Recoveries in all cases ranged between 62 and 107% (at 10, 50, and 100 ng g^-1), while intra-day and inter-day precision, expressed as relative standard deviation, RSD, was lower than 4% and 7%, respectively. In addition, limits of quantification (LOQs) ranged between 0.5 and 19 ng g^-1. The compounds presented a low matrix effect, between - 13 and 4%, while the expanded uncertainty U% estimated at the three spiking levels 10, 50, and 100 ng g^-1 was found below 49% in all cases. Finally, the validated method was applied to sea bream samples from an aquaculture farm located in the Mediterranean Sea, with one positive finding for the antibiotic trimethoprim at a concentration of 26 ng g^-1, presenting negligible human health risk.

Data analysis strategies for the characterization of chemical contaminant mixtures. Fish as a case study

Thousands of chemicals are potentially contaminating the environment and food resources, covering a wide spectrum of molecular structures, physico-chemical properties, sources, environmental behavior and toxic profiles. Beyond the description of the individual chemicals, characterizing contaminant mixtures in related matrices has become a major challenge in ecological and human health risk assessments. Continuous analytical developments, in the fields of targeted (TA) and non-targeted analysis (NTA), have resulted in ever larger sets of data on associated chemical profiles. More than ever, the implementation of advanced data analysis strategies is essential to elucidate profiles and extract new knowledge from these large data sets. Specifically focusing on the data analysis step, this review summarizes the recent progress in integrating data analysis tools into TA and NTA workflows to address the challenging characterization of chemical mixtures in environmental and food matrices. As fish matrices are relevant in both aquatic pollution and consumer exposure perspectives, fish was chosen as the main theme to illustrate this review, although the present document is equally relevant to other food and environmental matrices. The key features of TA and NTA data sets were reviewed to illustrate the challenges associated with their analysis. Advanced filtering strategies to mine NTA data sets are presented, with a particular focus on chemical filters and discriminant analysis. Further, the applications of supervised and unsupervised multivariate analysis methods to characterize exposure to chemical mixtures, and their associated challenges, is discussed.

Comparison of four different multiclass, multiresidue sample preparation methods in the analysis of veterinary drugs in fish and other food matrices

In 2018, AOAC International issued Standard Method Performance Requirements (SPMR) 2018.010 - Screening and Identification Method for Regulated Veterinary Drug Residues in Food. In response, we compared 4 different multiresidue methods of sample preparation using the same analytical method entailing ultrahigh-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). Tilapia was chosen for testing, and the analytes and monitoring levels were from SPMR 2018.010. The methods consist of efficient procedures with published validation results from the US Department of Agriculture (USDA), Food and Drug Administration (FDA), and Canadian Food Inspection Agency (CFIA), and an enhanced-matrix removal (EMR)-Lipid protocol from China. Each method was used to prepare 102 final extracts of tilapia spiked or not at different levels with the 78 targeted analytes plus metabolites. The same FDA/USDA rules of mass spectral identification were employed in all analyses to assess rates of false positives and negatives. Quantitative accuracy of the methods was also compared in terms of recoveries and reproducibility of spiked tilapia, incurred catfish, and spiked and certified reference material of bovine muscle. Each method yielded generally acceptable results for the targeted veterinary drugs, but the USDA "extract & inject" method was the fastest, simplest, and cheapest to achieve equally or more acceptable results for the widest scope of analytes for the tested food matrices.

Development of an enzyme-linked immunosorbent assay for the detection of mebendazole in chicken and mutton

Mebendazole (MBZ), a synthetic benzimidazole, is most widely used for the treatment of intestinal helminthiasis. In the present study, a hapten mimicking the MBZ structure was designed by introducing propanoic acid and coupling to carrier proteins by the active ester method to immunize New Zealand rabbits. A sensitive enzyme-linked immunosorbent assay (ELISA) was developed for the analysis of MBZ in food samples. The rabbit IgG based ELISA had a half-maximum inhibition concentration (IC₅₀) of 7.41 ng mL^-1, with a limit of detection of 0.27 ng mL^-1. The ELISA showed negligible cross reactivity (<1%) with structural analogs, including hydroxy-MBZ, albendazole, oxfendazole, fenbendazole, flubendazole and oxfendazole, except the value of 90.5% for amino-MBZ. The average recoveries of MBZ spiked in chicken and mutton muscle samples by the assay ranged from 84.31% to 106.28% and agreed well with those of high-performance liquid chromatography. The above results indicated that the generated anti-MBZ IgG-based ELISA showed promise in routine screening analysis of MBZ residues in food samples.

Focused ultrasound-based extraction for target analysis and suspect screening of organic xenobiotics in fish muscle

The development of multitarget and/or suspect screening methods for the analysis of xenobiotics in fish samples is compulsory due to the lack of works in the literature where a deep evaluation of the variables affecting extraction and clean-up steps is performed. The aim of the present work was to optimize and validate a multitarget (180 compounds) method for the analysis of priority and emerging xenobiotics in fish muscle using focused ultrasound-assisted solid-liquid extraction. From the different extraction solvents studied, a single extraction in cold acetonitrile rendered the best consensus results in terms of absolute recoveries and the number of target compounds extracted. Matrix effect was minimized using commercially available Captiva ND-Lipid filters, which provided clean extracts and satisfactory repeatability compared to other approaches. Absolute recoveries were corrected using matrix-matched calibration and apparent recoveries in the 43%-105%, 73%-131% and 78%-128% ranges were obtained at low (20 ng g^-1), medium (100 ng g^-1), and high (200 ng g^-1) spiking levels, respectively. A 60% of the xenobiotics showed limits of identification lower than 20 ng g^-1. The developed method was successfully applied to the quantification and suspect screening of samples bought in a local market (hake, gilt-head bream, sea bass and prawn) and fished (thicklip grey mullet) at the Urdaibai estuary (north of Spain). Food additives, antiparasitic drugs and PFOS were quantified at ng g^-1 level. Moreover, the targeted method was extended to the suspect screening, revealing the presence of plastic related products (caprolactam, phthalates, polyethylenglycols), pharmaceutical products (albendazole, mebendazole, valpromide) and pesticides or insect repellents (icaridin, myristyl sulfate, nootkatone). Therefore, FUSLE in cold acetonitrile combined with Captiva ND-Lipid filters and liquid chromatography tandem high-resolution mass spectrometry (LC-q-Orbitrap) were successfully applied to both multitarget quantitative analysis and suspect screening of approx. 17,800 compounds.

Analysis of peptide antibiotic residues in milk using liquid chromatography-high resolution mass spectrometry (LC-HRMS)

A liquid chromatography-high resolution mass spectrometry (LC-HRMS) method was developed and validated for the determination of residual peptide antibiotics (bacitracin A, colistin A and B, enramycin A and B, virginiamycin M1 and S1) in bovine milk. LC-HRMS accurate mass data provided the necessary selectivity and sensitivity to quantitate and identify these important antibiotics in milk at residue levels without extensive sample preparation. Milk samples were extracted using 0.3% formic acid in acetonitrile with 0.06% trifluoroacetic acid added to improve peptide recoveries. Sample clean-up was minimal with an aliquot of the extract evaporated and reconstituted in a formic acid/water-acetonitrile mixture and then filtered. LC separation was performed with 0.3% formic acid in the gradient to improve the peak shape and reproducibility of the peptide analytes. A Quadruple-Orbitrap HRMS instrument with full-scan MS1 data collection followed by all-ion-fragmentation was used to obtain the exact mass of the precursor and confirmatory product ions. One advantage of LC-HRMS is that a combination of multiple precursor ions, including different charge states or adducts, can be used for quantification. The method was validated at four concentration levels ranging from 12.5 to 200 ng/g in three types of bovine milk. For bacitracin A, colistins and enramycins, the average recoveries compared to solvent standards ranged between 70% and 120%. Average recoveries for virginiamycin residues in milk extracts were unacceptably high (up to 138%) using solvent standards, but recoveries using matrix-matched calibration were determined to be 90-115%. Matrix effects were found to be less than 25% for the other analytes when internal standard correction was used for the colistins. Intra-day relative standard deviations were generally below 15%. The method detection limits for the peptide antibiotic residues in milk (0.5 to 5.5 ng/g) were well below regulatory levels of concern.

Comparison of data acquisition modes with Orbitrap high-resolution mass spectrometry for targeted and non-targeted residue screening in aquacultured eel

RATIONALE

A current trend in monitoring chemical contaminants in animal products is to use high-resolution mass spectrometry (HRMS). In this study, several HRMS data acquistion modes using Orbitrap MS for simultaneous full-scan MS in combination with MS2 analysis were evaulated for their effectiveness in detecting and identifying both targeted and non-targeted veterinary drug residues in aquacultured eel samples.

METHODS

Sample preparation consisted of an acidic acetonitrile extraction with solid-phase extraction cleanup for analysis using LC/HRMS. Different data acquisition methods, including full-scan MS with non-targeted all ion fragmentation (AIF), multiplexed or variable data-independent analysis (mDIA or vDIA), targeted data-dependent MS2 (DDMS2), and parallel reaction monitoring (PRM) acquisition, were explored. The methods were evaluated with fortified eel tissue and imported eel samples to determine how many analytes could be detected and identified.

RESULTS

For non-targeted data acquisition, the number of analytes detected using DIA methods matched the results obtained by AIF, but the resulting product ion scans were more diagnostic because characteristic ions were predominant in the DIA MS2 spectra. In targeted analysis for a limited list of 68 compounds, full-scan MS followed by PRM was advantageous compared with DDMS2 because high-quality MS2 spectra were generated for almost all the analytes at target testing levels.

CONCLUSIONS

For residue screening, AIF has fast MS1 scan speed with adequate detection of product ions but may lead to false positive findings. DIA methods are better suited to monitor for both targeted and non-targeted compounds because they generate more characteristic MS2 spectra for retrospective library searching. For follow-up targeted analysis, PRM is prefered over DDMS2 when searching for a limited set of compounds.

Rapid screening of amitraz and its metabolite residues in honey using a quick, easy, cheap, effective, rugged, and safe extraction method coupled with UHPLC and Q Exactive

A method for determining amitraz and 2,4-dimethylaniline in honey was established by using ultra-high-performance liquid chromatoghaphy and Q Exactive after applying quick, easy, cheap, effective, rugged, and safe extracting process. A suitable extraction method was designed to extract the amitraz and 2,4-dimethylaniline after a suitable amount of honey samples was dissolved. A Thermo Syncronis C₁₈ column (100 × 2.1 mm, 1.7 μm) was used for chromatographic separation of the samples. Then the two compounds were quantitatively analyzed via a program of Q Exactive. The linearity of amitraz and 2,4-dimethylaniline was good in the concentration range of 0.5-100 μg/L, and the correlation coefficient R² was >0.99. The average recovery and relative standard deviation of each component were 81.3-90.0% and 5.1-7.2%. The 24- and 48-h test results showed that the sample needed to be tested within 24 h. The limit of detection was 0.1 μg/kg for amitraz and 2,4-dimethylaniline, whereas for both the limit of quantitation was 0.3 μg/kg.

Extended liquid chromatography high resolution mass spectrometry screening method for veterinary drug, pesticide and human pharmaceutical residues in aquaculture fish

A liquid chromatography high resolution mass spectrometry (LC-HRMS) screening method was developed previously to analyze for veterinary drug residues commonly found in different types of aquaculture products. This method has been further evaluated for its feasibility to detect several other classes of compounds that might also be a concern as possible contaminants in farmed tilapia, salmon, eel and shrimp. Some chemicals could contaminate water sources used in aquaculture production through agricultural run-off. These compounds include several widely used triazine herbicides, organophosphate and carbamate pesticides, as well as various discarded human pharmaceuticals. Other possible contaminants investigated were selected disinfectants, some newer antibiotics, growth promoters, and various parasiticides. The sample preparation consisted of an acidic acetonitrile extraction followed by solid-phase extraction clean-up. Data were collected with a quadrupole-Orbitrap MS using both non-targeted and targeted acquisition. This rapid clean-up procedure and HRMS detection method described previously for veterinary drug residues also worked well for many other types of compounds. Most analytes had screening limit levels between 0.5-10 ng/g in the matrices examined using exact mass identification criteria. The strategy described in this paper for testing the performance of additional analytes will help expand the applicability of the HRMS procedure as aquaculture samples can now be analyzed for a wider range of contaminants.

Detection and quantification of 47 antibiotic residues in farmed European sea bass (Dicentrarchus labrax) using a multi-class and multi-residue UHPLC-MS/MS method

In the present study, a multi-class multi-residue method for the simultaneous detection and determination of antibiotics in European sea bass (Dicentrarchus labrax) was developed and validated. The method based on UHPLC-MS/MS proved to be a rapid, highly selective and sensitive tool, requiring minimum sample preparation, for screening and detection of 47 compounds from eight different classes. The validation was performed according to EU regulation 2002/657/EC, proving the method's suitability for application in routine analysis. The method was applied to the analysis of 30 samples of farmed European sea bass purchased in different supermarkets in Portugal. Antibacterial residues were detected in 6 of the 30 analysed samples, namely enrofloxacin and oxytetracycline, in concentrations ranging from 0.1 to 12 µg kg^-1.

Comprehensive characterization of in vivo metabolic profile of Polygalae radix based on ultra-high-performance liquid chromatography-tandem mass spectrometry

In this study, a novel analysis strategy for progressively targeted screening and characterization of drug ingredients from in vitro to in vivo was proposed based on ultra-high performance liquid chromatography-tandem mass spectrometry for comprehensive characterization of in vivo metabolic profile of Polygalae radix (PR). First, an in vitro chemical profile of PR was described with the assistance of UNIFI™ software. The characteristic neutral small molecule losses were summarized to distinguish different chemical structures in the PR extract. Second, the in vitro intestinal microflora metabolism model was applied to describe an in vitro metabolic profile of the main ingredients of PR. The metabolic rule and metabolites were integrated for subsequent targeted screening of metabolites in vivo. Finally, an integrated strategy was established and applied to screen and characterize the major absorbed components in vivo, including blood, urine, brain, feces, and liver, based on the prototypes and metabolic rules obtained in vitro. As a result, in vitro and in vivo metabolic profiles of PR were effectively depicted. A total of 136 compounds were isolated and identified from the crude extract in vitro, and 12 compounds were reported for the first time based on the proposed fragmentations. A total of 13, 32, and 3 compounds were identified and characterized in the dosed plasma, liver, and brain, respectively. A total of 40 and 73 compounds were identified in urine and feces, respectively. This strategy not only provided a comprehensive insight into the chemical and metabolic profiles of PR but also presented a new perspective for the discovery of new drugs for medicinal application.