Qualitative Multiresidue Screening Method for 143 Veterinary Drugs and Pharmaceuticals in Milk and Fish Tissue Using Liquid Chromatography Quadrupole-Time-of-Flight Mass Spectrometry

Development and evaluation of a comprehensive workflow for suspect screening of exposome-related xenobiotics and phase II metabolites in diverse human biofluids

Suspect and non-target screening (SNTS) methods are being promoted in order to decode the human exposome since a wide chemical space can be analysed in a diversity of human biofluids. However, SNTS approaches in the exposomics field are infra-studied in comparison to environmental or food monitoring studies. In this work, a comprehensive suspect screening workflow was developed to annotate exposome-related xenobiotics and phase II metabolites in diverse human biofluids. Precisely, human urine, breast milk, saliva and ovarian follicular fluid were employed as samples and analysed by means of ultra-high performance liquid chromatography coupled with high resolution tandem mass spectrometry (UHPLC-HRMS/MS). To automate the workflow, the "peak rating" parameter implemented in Compound Discoverer 3.3.2 was optimized to avoid time-consuming manual revision of chromatographic peaks. In addition, the presence of endogenous molecules that might interfere with the annotation of xenobiotics was carefully studied as the employment of inclusion and exclusion suspect lists. To evaluate the workflow, limits of identification (LOIs) and type I and II errors (i.e., false positives and negatives, respectively) were calculated in both standard solutions and spiked biofluids using 161 xenobiotics and 22 metabolites. For 80.3 % of the suspects, LOIs below 15 ng/mL were achieved. In terms of type I errors, only two cases were identified in standards and spiked samples. Regarding type II errors, the 7.7 % errors accounted in standards increased to 17.4 % in real samples. Lastly, the use of an inclusion list for endogens was favoured since it avoided 18.7 % of potential type I errors, while the exclusion list caused 7.2 % of type II errors despite making the annotation workflow less time-consuming.

Occurence of antimicrobial residues in milk and labneh consumed in Lebanon

Antimicrobials are administered in livestock for different uses leading to milk contamination and several undesirable effects. Because there is a lack of surveillance of antimicrobial residues (AMRs) in milk and dairy products in Lebanon, this study aims to determine the occurrence of AMRs in 90 Lebanese samples of milk and labneh (concentrated yoghurt). Multi-residue screening methods with suitable sample preparations were applied to detect 71 AMRs in milk and labneh, respectively, using LC-MS/MS. Of the total number of samples, 71% was contaminated with AMRs and (fluoro)quinolones and macrolides were the most detected families. Additional confirmation tests proved that 6.7% of the milk samples were non-compliant for the macrolides tilmicosin, tulathromycin and spiramycin. Moreover, some labneh prepared from contaminated milk samples was analysed to determine the fate of AMRs during the manufacturing process. The results showed that some AMRs could be concentrated, eliminated or degraded, based on their physicochemical characteristics.

Targeted Analysis of Veterinary Drugs in Food Samples by Developing a High-Resolution Tandem Mass Spectral Library

Veterinary drug residues present in foods can pose severe health threats to the population. The present study aims to develop a high-resolution mass spectral library of 158 veterinary drugs of 16 different classes for their rapid identification in food samples through liquid chromatography-high-resolution electrospray ionization-tandem mass spectrometry (LC-HR-ESI-MS/MS). Standard drugs were pooled according to their log P values and exact masses before analysis. Spectra were collected at system automated collision energy, i.e., of 25-60 eV and four predetermined collision energies (10, 20, 30, and 40 eV) for each compound using a schedule precursor list of [M + H]+, [M + Na]+, and [M + NH4]+ ions. The utility of the developed database was checked by analyzing food samples. A total of 17 veterinary drugs based on the reference standard retention times (RTs), HR-MS spectra, and MS/MS spectra were identified in the analyzed samples. Moreover, five veterinary drugs were selected for quantitative analysis, including doxycycline hyclate, lincomycin, sulfasalazine, moxifloxacin, and diphenoxylate, using liquid chromatography-ion trap mass-spectrometry (LC-IT-MS). Concentrations of the drug were obtained to vary from 0.0805 to 0.9731 mg/kg in food samples and were found to be exceeded in most of the cases as per the maximum residue levels described by Food and Agriculture Organization (FAO)/World Health Organization (WHO). The MS data were submitted to the MetaboLights online database (MTBLS2914). This study will help in the high-throughput screening of multiclass veterinary drugs in foodstuffs.

A Review on Pretreatment and Analysis Methods of Polyether Antibiotics in Complex Samples

Polyether antibiotics (PAs) are the anti-coccidiosis drugs used for treating and preventing coccidiosis. Studies show the residues of these antibiotics in food cause adversities and threaten human health. PAs thus need robust, rugged, and accurate methods for their analysis. This review encompasses pretreatment and detection methods of PAs in diverse matrices since 2010. Both conventional and developed methods are part of the pretreatments, such as dispersive liquid-liquid microextraction, solid-phase extraction, solid-phase microextraction, solvent front position extraction, QuEChERS (Quick Easy Cheap Effective Rugged and Safe), supercritical fluid extraction, and others. The analysis methods involve liquid chromatography coupled with detectors, sensors, etc. The pros and cons of various techniques for PAs have been discussed and future tendencies are proposed.

A review on recent advances in mass spectrometry analysis of harmful contaminants in food

Food safety is a widespread global concern with the emergence of foodborne diseases. Thus, establishing accurate and sensitive detection methods of harmful contaminants in different food matrices is essential to address and prevent the associated health risks. Among various analytical tools, mass spectrometry (MS) can quantify multiple impurities simultaneously due to high resolution and accuracy and can achieve non-target profiling of unknown pollutants in food. Therefore, MS has been widely used for determination of hazardous contaminants [e.g., mycotoxin, pesticide and veterinary drug residues, polychlorinated biphenyls (PCBs), dioxins, acrylamide, perfluorinated compounds (PFCs) and p-Phenylenediamine compounds (PPDs) in food samples]. This work summarizes MS applications in detecting harmful contaminants in food matrices, discusses advantages of MS for food safety study, and provides a perspective on future directions of MS development in food research. With the persistent occurrence of novel contaminants, MS will play a more and more critical role in food analysis.

A one-step solid-phase extraction with UHPLC-MS/MS for fast and accurate determination of multi-class veterinary drugs in animal muscles

Excessive use of veterinary drugs in livestock growth poses a threat to food safety. It is, however, challenging to quantify these multi-class veterinary drugs within animal muscles, because of their varied physicochemical properties. In this work, we presented a simple, efficient and sensitive method for the simultaneous determination of multi-class veterinary drugs with ultra-high-performance liquid chromatography-tandem mass spectrometry (UHPLC-MS/MS). The method involves a highly efficient extraction using a EDTA (pH 7)-ACN (30:70, v/v) solvent system, followed by a one-step solid-phase extraction cleanup approach with PRiME HLB sorbent (Reversed-phase N-vinylpyrrolidone and divinylbenzene copolymer). For all the analytes, over a wide range of polarity, satisfactory recoveries were obtained between 70% and 120%, with relative standard deviations <15%. Excellent sensitivities were achieved with the limits of quantification ranging from 0.2 μg/kg to 3.0 μg/kg. This developed method provides a new targeted strategy for the analysis of multi-class veterinary drugs in muscle matrices.

Critical Evaluation of Two Qualitative Analytical Approaches for Multiclass Determination of Veterinary Drugs in Bovine Muscle Using UHPLC-Q-Orbitrap: The Wind of Change in Brazilian Monitoring

Food safety is recognized as a main requirement for consumers, food industries, and official laboratories. Here, we present the optimization and screening qualitative validation of two multianalyte methods in bovine muscle tissues by ultra-high-performance liquid chromatography coupled to high-resolution mass spectrometry with an Orbitrap-type analyzer, operated with a heated ionization source in positive and negative mode. This aims for not only the simultaneous detection of veterinary drugs regulated in Brazil but also the prospection of antimicrobials not yet monitored. Two different sample preparation procedures were applied: method A-generic solid-liquid extraction with 0.1% formic acid (v/v) in an aqueous solution of EDTA 0.1% (w/v)-acetonitrile-methanol (1:1:1, v/v/v), followed by an additional ultrasound-assisted extraction and method B-QuEChERS. In both procedures, selectivity showed satisfactory conformity. From a detection capability (CCβ) equivalent to ½ the maximum residue limit, >34% of the analyte resulted in a false positive rate of <5%, preponderant by the QuEChERS method, which exhibited a higher yield of the sample. The results showed the potential application of both procedures in the routine analysis of foods by official laboratories, enabling the expansion of this methodological portfolio as well as its analytical scopes, thus optimizing the control of residues of veterinary drugs in the country.

Advances in solid-phase extraction techniques: Role of nanosorbents for the enrichment of antibiotics for analytical quantification

Antibiotics are life-saving medications for treating bacterial infections; however it has been discovered that resistance developed by bacteria against these incredible agents is the primary contributing factor to rising global mortality rates. The fundamental cause of the emergence of antibiotic resistance in bacteria is the presence of antibiotic residues in various environmental matrices. Although antibiotics are present in diluted form in environmental matrices like water, consistent exposure of bacteria to these minute levels is enough for the resistance to develop. So, identifying these tiny concentrations of numerous antibiotics in various and complicated matrices will be a crucial step in controlling their disposal in those matrices. Solid phase extraction, a popular and customizable extraction technology, was developed according to the aspirations of the researchers. It is a unique alternative technique that could be implemented either alone or in combination with other approaches at different stages because of the multitude of sorbent varieties and techniques. Initially, sorbents are utilized for extraction in their natural state. The basic sorbent has been modified over time with nanoparticles and multilayer sorbents, which have indeed helped to accomplish the desired extraction efficiencies. Among the current traditional extraction techniques such as liquid-liquid extraction, protein precipitation, and salting out techniques, solid-phase extractions (SPE) with nanosorbents are most productive because, they can be automated, selective, and can be integrated with other extraction techniques. This review aims to provide a broad overview of advancements and developments in sorbents with a specific emphasis on the applications of SPE techniques used for antibiotic detection and quantification in various matrices in the last two decades.

Geraniol-a potential alternative to antibiotics for bovine mastitis treatment without disturbing the host microbial community or causing drug residues and resistance

Mastitis is one of the most prevalent diseases of dairy cows. Currently, mastitis treatment in dairy cows is mainly based on antibiotics. However, the use of antibiotics causes adverse effects, including drug resistance, drug residues, host-microbiome destruction, and environmental pollution. The present study sought to investigate the potentiality of geraniol as an alternative to antibiotics for bovine mastitis treatment in dairy cows. Additionally, the effectiveness of treatment, improvement in inflammatory factors, the influence on microbiome, presence of drug residues, and drug resistance induction were compared and analyzed comprehensively.Geraniol showed an equivalent therapeutic rate as antibiotics in the mouse infection model and cows with mastitis. Moreover, geraniol significantly inhibited the pathogenic bacteria and restored the microbial community while increasing the abundance of probiotics in milk. Notably, geraniol did not destroy the gut microbial communities in cows and mice, whereas antibiotics significantly reduced the diversity and destroyed the gut microbial community structure. Additionally, no geraniol residue was detected in milk four days after treatment discontinuation, but, antibiotic residues were detected in milk at the 7th day after drug withdrawal. In vitro experiments revealed that geraniol did not induce drug resistance in the Escherichia coli strain ATCC25922 and Staphylococcus aureus strain ATCC25923 after 150 generations of culturing, while antibiotics induced resistance after 10 generations. These results suggest that geraniol has antibacterial and anti-inflammatory effects similar to antibiotics without affecting the host-microbial community structure or causing drug residues and resistance. Therefore, geraniol can be a potential substitute for antibiotics to treat mastitis or other infectious diseases and be widely used in the dairy industry.

An Overview of Analytical Methods to Determine Pharmaceutical Active Compounds in Aquatic Organisms

There is increasing scientific evidence that some pharmaceuticals are present in the marine ecosystems at concentrations that may cause adverse effects on the organisms that inhabit them. At present, there is still very little scientific literature on the (bio)accumulation of these compounds in different species, let alone on the relationship between the presence of these compounds and the adverse effects they produce. However, attempts have been made to optimize and validate analytical methods for the determination of residues of pharmaceuticals in marine biota by studying the stages of sample treatment, sample clean-up and subsequent analysis. The proposed bibliographic review includes a summary of the most commonly techniques, and its analytical features, proposed to determine pharmaceutical compounds in aquatic organisms at different levels of the trophic chain in the last 10 years.

High-throughput screening of 756 chemical contaminants in aquaculture products using liquid chromatography/quadrupole time-of-flight mass spectrometry

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A high-throughput screening method was developed for aquaculture products.

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Modified QuEChERS extraction was used in couple with LC/Q-TOF-HRMS.

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A mega-database was established for 756 multiclass chemical contaminants.

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The method had desirable sensitivity, recovery and repeatability.

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Analysis of real-life samples evidenced applicability of the proposed method.

A high-throughput screening method embracing 756 multiclass chemical contaminants in aquaculture products was developed using modified QuEChERS extraction coupled with liquid chromatography/quadrupole time-of-flight mass spectrometry. A mega-database with retention time/accurate mass data for 524 pesticides, 182 veterinary drugs, 32 persistent organic pollutants and 18 marine toxins was established for compound identification via retrospective library searching. In the four representative matrices (muscle tissues of tilapia and grouper, and edible portions of oyster and scallop), all the database compounds showed acceptable recovery and repeatability with the screening detection limit and limit of quantification below 0.01 mg/kg for >90% of them. The matrix-matched calibration revealed acceptable quantitative property of the method in terms of linear range, linearity, and matrix effect, and fish muscle samples showed stronger matrix effect than shellfish samples. Analysis of 64 real-life samples from aquaculture farms and retail markets evidenced applicability of the proposed method to high-throughput screening scenarios.

Rapid determination of 103 common veterinary drug residues in milk and dairy products by ultra performance liquid chromatography tandem mass spectrometry

A multi-residue method has been developed for the identification and quantification of 103 common veterinary drug residues in milk and dairy Products. This method was based on QuEChERS with dispersive solid-phase where C18 sorbent and anhydrous sodium sulfate were used to sample purification. After evaporation and reconstitution, the samples were analyzed by ultra-performance liquid chromatography-tandem mass spectrometry. The mean recovery results were all higher than 60% except ampicillin, pipemidic acid, enoxacin, and estriol, and the relative standard deviation was <20.0%. The limit of quantification ranged between 0.1 and 5 μg/kg for milk and between 0.5 and 25 μg/kg for milk powder. It was successfully used to detect residues of veterinary drug in real samples. This study proposes a simple and fast analytical method for monitoring multi-class veterinary drug residues to ensure food safety.

Multi-class, multi-residue determination of 132 veterinary drugs in milk by magnetic solid-phase extraction based on magnetic hypercrosslinked polystyrene prior to their determination by high-performance liquid chromatography-tandem mass spectrometry

A quantitative multi-class multi-residue analytical method was developed for the determination of veterinary drugs in milk by high-performance liquid chromatography - tandem mass spectrometry (HPLC-MS/MS). A total of 132 veterinary drugs investigated belonged to almost 15 classes including sulfonamides, β-lactams, tetracyclines, quinolones, macrolides, nitrofurans, nitroimidazoles, phenicols, lincosamides, pleuromutilins, macrocyclic lactones, quinoxaline antibiotics, benzimidazoles, anthelmintics, coccidiostats and some others. A magnetic solid-phase extraction procedure was developed using magnetic hypercrosslinked polystyrene (HCP/Fe₃O₄) for the sample preparation prior to HPLC-MS/MS without deproteinization step. The results indicated recoveries of 85-107% for 14 sulfonamides, 85-120% for 13 β-lactams, 89-115% for 4 tetracyclines, 82-119% for 14 quinolones, 82-115% for 8 macrolides, 97-109% for 4 nitrofurans, 84-115% for 10 nitroimidazoles, 89-114% for 3 phenicols, 86-111% for 3 lincosamides, 97-102% for 2 pleuromutilins, 72-88% for 4 macrocyclic lactones, 87-104% for 4 quinoxaline antibiotics, 76-119% for 21 benzimidazoles, 79-115% for 12 anthelmintics, 81-118% for 12 coccidiostats and 75-119 % for 5 unclassified drugs, with relative standard deviations (RSDs) of less than 20%, and the LOQs ranged from 0.05 to 1 μg kg^-1. This methodology was then applied to field-collected real milk samples and trace levels of some veterinary drugs were detected.

Multiclass Comparative Analysis of Veterinary Drugs, Mycotoxins, and Pesticides in Bovine Milk by Ultrahigh-Performance Liquid Chromatography-Hybrid Quadrupole-Linear Ion Trap Mass Spectrometry

A multiclass and multiresidue method for simultaneously screening and confirming veterinary drugs, mycotoxins, and pesticides in bovine milk was developed and validated with ultrahigh-performance liquid chromatography–hybrid quadrupole–linear ion trap mass spectrometry (UHPLC-Qtrap-MS). A total of 209 targeted contaminants were effectively extracted using an optimized QuEChERS method. Quantitative and qualitative confirmation were achieved simultaneously by multiple reaction monitoring–information-dependent acquisition–enhanced product ion (MRM-IDA-EPI) scan mode. The validation results exhibited a good sensitivity with the LOQs of 0.05–5 μg/kg, which was satisfactory for their MRLs in China or EU. The recoveries of in-house spiked samples were in the range of 51.20–129.76% with relative standard deviations (RSD) between replicates (n = 3) 0.82% and 19.76%. The test results of 140 milk samples from supermarkets and dairy farms in China showed that cloxacillin, aflatoxin M1, acetamiprid, and fipronil sulfone were found with lower concentrations. Combined with the residue results from the literature, penicillin G and cloxacillin (beta-lactams), enrofloxacin and ciprofloxacin (fluoroquinolones), and sulfamerazine (sulfonamides) were more frequently detected in different countries and need to receive more attention regarding their monitoring and control.

Occurrence of pharmaceuticals in seafood from two Brazilian coastal areas: Implication for human risk assessment

Pharmaceuticals (PhACs) are considered emerging contaminants with potential accumulation in aquatic organisms. Thus, seafood consumption may cause long-term effects and health risk for consumers. In the present study, the occurrence of PhACs in seafood from two Brazilian coastal areas, Sepetiba Bay (n = 43) and Parnaiba Delta River (n = 48), was determined for the first time, and their potential risk for human health was assessed. An eco-friendly multi-analytes method was used, after being validated for the different types of matrices (mussels, fatty and lean fish). All compounds under study were detected at least in four seafood species, including chloramphenicol, an antibiotic prohibited in animal foods. Most PhACs had mean concentrations below limit of quantification. Ibuprofen and other nonsteroidal anti-inflammatory drugs (NSAIDs), as well as simvastatin and carbamazepine were the main PhACs bioaccumulated in edible parts of seafood species from Brazil. The high trophic level carnivorous species, snook, was the most contaminated by NSAIDs, while bivalves were the seafood more contaminated by lipid regulators. The profile of contamination did not vary among different types of matrix, except in relation to carbamazepine and ketoprofen. These PhACs were more abundant in species from Sepetiba Bay, an area highly impacted by human influence. The estimated daily exposure for Brazilian population that consumes the studied species was up to 20.3 ng/kg bw/day via carib pointed-venus and 25.7 ng/kg bw/day via snooks, lower than acceptable daily intake. Thus, consumption of seafood species from Sepetiba Bay and Parnaiba Delta River seems to be safe to the population in what concerns the PhACs studied.

Lanthanide type of cerium sulfide embedded carbon nitride composite modified electrode for potential electrochemical detection of sulfaguanidine

Environmental sustainability is threatened by the widespread exploitation and unfettered release of chemical pollutants that require immediate detection and eradication. An instantaneous quantification technique is essential to understand the physiological roles of the antibacterial drug sulfaguanidine (SGN) in biological systems. The present work features the green and environmentally benign synthesis of rare earth metal sulfide nanorods incorporated carbon nitrides sheets (Ce₂S₃@CNS) by deep eutectic solvent-based fabrication with remarkable electrochemical properties. The morphological and structural analyses of the prepared electrocatalyst were characterized using various techniques including SEM, XRD, XPS, and EIS. The heterojunction of regimented structures bids synergistic quantum confinement effects and refines charge carriers endorsing enormous active sites. Furthermore, the obtained Ce₂S₃@CNS/GCE possess an exceedingly lower limit of detection (0.0053 μM) and high sensitivity of 8.685 μA·μM^-1·cm^-2 with superior electrocatalytic action and virtuous stability for the detection of SGN. This modified electrode could afford linearity in the range 0.01-1131.5 μM measured at 0.95 V (vs. Ag/AgCl) correlated to the concentration of SGN. Examining the real samples with this advanced electrocatalyst would support its hands-on applications in everyday life. Development of such innovative architectures with fewer energy necessities and nominal by-products scripts the superiority in characteristic synthetic methodology following the guidelines of green chemistry.

Determination of Anthelmintic and Antiprotozoal Drug Residues in Fish Using Liquid Chromatography-Tandem Mass Spectrometry

The objective of this study is to develop a comprehensive and simple method for the simultaneous determination of anthelmintic and antiprotozoal drug residues in fish. For sample preparation, we used the "quick, easy, cheap, effective, rugged, and safe" (QuEChERS) method with a simple modification. The sample was extracted with water and 1% formic acid in acetonitrile/methanol (MeCN/MeOH) (95:5, v/v), followed by phase separation (salting out) with MgSO4 and NaCl (4:1, w/w). After centrifugation, an aliquot of the extract was purified by dispersive solid-phase extraction (d-SPE) prior to liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysis. The method was validated at three concentration levels for all matrices, in accordance with the Codex guidelines (CAC/GL-71). Quantitative analysis was performed using the method of matrix-matched calibration. The recoveries were between 60.6% and 119.9%, with coefficients of variation (CV) <30% for all matrices. The limit of quantitation (LOQ) of the method ranged from 0.02 μg kg-1 to 4.8 μg kg-1 for all matrices. This comprehensive method can be used for the investigation of both anthelmintic and antiprotozoal drugs belonging to different chemical families in fishery products.

Veterinary Drug Residues in Animal-Derived Foods: Sample Preparation and Analytical Methods

Veterinary drugs are used to treat livestock and aquatic diseases and thus are introduced into animal-derived foods, endangering consumer health and safety. Antibiotic resistance is rapidly becoming a major worldwide problem, and there has been a steady increase in the number of pathogens that show multi-drug resistance. Illegal and excessive use of veterinary drugs in animals and aquaculture has serious adverse effects on humans and on all other environmental organisms. It is necessary to develop simple extraction methods and fast analytical methods to effectively detect veterinary drug residues in animal-derived foods. This review summarizes the application of various sample extraction techniques and detection and quantification methods for veterinary drug residues reported in the last decade (2010-2020). This review compares the advantages and disadvantages of various extraction techniques and detection methods and describes advanced methods, such as those that use electrochemical biosensors, piezoelectric biosensors, optical biosensors, and molecularly imprinted polymer biosensors. Finally, the future prospects and trends related to extraction methods, detection methods and advanced methods for the analysis of veterinary drug residues in animal-derived foods are summarized.

Pharmacokinetics, bioavailability, and tissue disposal profiles of Tiamulin fumarate in Nile tilapia (Oreochromis niloticus) following oral and intravenous administrations

Tiamulin fumarate (TIF) is a pleuromutilin antibiotic and has high activity against animal bacterial pathogens including aquatic bacterial pathogens. However, its pharmacokinetic profiles, tissue distribution characteristics and bioavailability in aquatic animals remain unknown. The objective of this study was to investigate the pharmacokinetics and tissue distribution regularities of TIF in tilapia (Oreochromis niloticus) following a single oral (PO) dose of 20 mg/kg body weight (bw) and a single intravenous (IV) dose of 5 mg/kg bw at 22 ± 1°C, respectively. TIF concentrations in tilapia plasma and tissues were determined using the isotope dilution HPLC-HESI-MS/MS procedure, which was validated according to the guidelines defined by US Food and Drug Administration. TIF was well distributed throughout the body compartments of tilapia judged by the apparent volume of distribution (V_d ) >1 L/kg (6.69 L/kg PO and 1.78 L/kg IV). TIF had a short mean residence time (MRT; 22.82 h PO and 14.61 h IV) and quick total body clearance (CL_b ) (0.62 L kg^-1  h^-1 PO and 0.60 L kg^-1  h^-1 IV). The total area under the curve (AUC_tot ) of plasma were 32.25 μg h^-1  ml^-1 (PO) and 8.30 μg h^-1  ml (IV), respectively, and the oral absolute bioavailability (F%) of TIF was calculated to be approximately 97.1%. For tissue distribution, high concentrations of TIF were found in kidney, and the longest MRT was recorded in bile. The withdrawal time (WT) of TIF in muscle, skin, liver, kidney, gill, and bile was 3.75 (4) and 1.79 (2), 1.77 (2) and 2.06 (3), 6.41 (7) and 1.97 (2), 6.95 (7) and 3.98 (4), 4.92 (5) and 2.36 (3), and 7.06 (8) and 6.16 (7) days after PO and IV administration, respectively. The present investigations indicated that TIF was quickly absorbed, well distributed, rapidly eliminated in tilapia, and it could serve as reference data for establishing use regimen and provide useful information for the further development of TIF in aquaculture.

FoodOmicsGR_RI. A Consortium for Comprehensive Molecular Characterisation of Food Products

The national infrastructure FoodOmicsGR_RI coordinates research efforts from eight Greek Universities and Research Centers in a network aiming to support research and development (R&D) in the agri-food sector. The goals of FoodOmicsGR_RI are the comprehensive in-depth characterization of foods using cutting-edge omics technologies and the support of dietary/nutrition studies. The network combines strong omics expertise with expert field/application scientists (food/nutrition sciences, plant protection/plant growth, animal husbandry, apiculture and 10 other fields). Human resources involve more than 60 staff scientists and more than 30 recruits. State-of-the-art technologies and instrumentation is available for the comprehensive mapping of the food composition and available genetic resources, the assessment of the distinct value of foods, and the effect of nutritional intervention on the metabolic profile of biological samples of consumers and animal models. The consortium has the know-how and expertise that covers the breadth of the Greek agri-food sector. Metabolomics teams have developed and implemented a variety of methods for profiling and quantitative analysis. The implementation plan includes the following research axes: development of a detailed database of Greek food constituents; exploitation of "omics" technologies to assess domestic agricultural biodiversity aiding authenticity-traceability control/certification of geographical/genetic origin; highlighting unique characteristics of Greek products with an emphasis on quality, sustainability and food safety; assessment of diet's effect on health and well-being; creating added value from agri-food waste. FoodOmicsGR_RI develops new tools to evaluate the nutritional value of Greek foods, study the role of traditional foods and Greek functional foods in the prevention of chronic diseases and support health claims of Greek traditional products. FoodOmicsGR_RI provides access to state-of-the-art facilities, unique, well-characterised sample sets, obtained from precision/experimental farming/breeding (milk, honey, meat, olive oil and so forth) along with more than 20 complementary scientific disciplines. FoodOmicsGR_RI is open for collaboration with national and international stakeholders.

Characteristics of veterinary antibiotics in intensive livestock farming watersheds with different liquid manure application programs using UHPLC-q-orbitrap HRMS combined with on-line SPE

Composted livestock manures, in both solid and liquid form, are used as fertilizers in cropland. However, excess solid and liquid manures in agricultural watersheds are considered as nonpoint pollution sources because of their high nutrient and heavy metal contents of, as well as their antibiotic contents, especially veterinary antibiotics (VAs). In this study, 21 VAs under nine classes (i.e., cephems, ionophores, lincosamides, penicillins, pleuromutilins, quinolones, streptogramins, sulfonamides, and tetracyclines) found in agricultural watersheds were simultaneously analyzed via UHPLC-q-orbitrap high-resolution mass spectrometry using an on-line solid-phase extraction system. The residues of VAs in the surface water of two intensive livestock rearing watersheds (Cheongmi and Gwangcheon streams) in Korea were successfully quantified, and the values were found to range from 1.84 ± 0.42 ng L^-1 to 835.6 ± 31.9 ng L^-1. Time lags of 2-3 months were observed between the periods of liquid manure application and the periods with the maximum concentrations of VAs. In both watersheds, samples from points close to areas with extensive application of liquid manure exhibited high concentrations of most of the 21 VAs. Between the watersheds, the one with heavier application of liquid manure showed higher concentrations of the target VAs. To the best of our knowledge, this study represents the first attempt at evaluating the correlation between liquid manure application and environmental occurrence of VAs in surface water. The findings reveal that liquid manure application plays an important role in introducing VAs into aquatic environments.

Untargeted multi-residue method for the simultaneous determination of 141 veterinary drugs and their metabolites in pork by high-performance liquid chromatography time-of-flight mass spectrometry

A rapid, simple and generic analytical method has been developed for the analysis of veterinary drugs in pork by a quadrupole time-of-flight mass spectrometry (Q-TOF MS). This method allows for the simultaneous identification, screening and quantitation of 141 veterinary drug residues and metabolites from eighteen different classes. After extraction with acetonitrile/water and clean-up with C₁₈ cartridges, the samples were analyzed by HPLC-Q-TOF MS. Validation of this method consisted of confirmation of identity, selectivity, linearity, limit of detection (LOD), lowest limit of quantification (LLOQ), matrix effect, recovery, precision and applicability of the method. Identification of the analytes was based on accurate mass measurements. The characteristic fragments were obtained by collisional experiments for a more reliable identification. The procedure was then applied to real pork samples. Sulfamethazine was detected in one sample and its metabolites were successfully found in one single run. This approach proved to be satisfactory for routine analysis.

Rapid Screening and Quantification of Multi-Class Multi-Residue Veterinary Drugs in Pork by a Modified Quechers Protocol Coupled to UPLC-QOrbitrap HRMS

Background:

A rapid and simple analytical method for the screening and quantification of multi-residues was established by a quick, easy, cheap, effective, rugged and safe (QuEChERS) approach coupled to ultra-performance liquid chromatography and electrospray ionization quadrupole orbitrap high-resolution mass spectrometry (UPLC-Q-Orbitrap HRMS). A total number of 59 veterinary drugs were investigated, which belonged to 12 classes, such as β-agonist, quinolones, sulfonamides, tetracyclines, lincomycin series, triphenylmethane, nitroimidazoles, macrolides, amide alcohols, quinoxalines, steroid hormone and sedatives.

Methods:

The factors which influence the determination of veterinary drugs residues, such as mobile phase, extract solvent, clean up sorbent, and re-dissolved solvent, were optimized by the single factor experiment. The method was sufficiently validated by using the parameters of linearity, sensitivity, accuracy, and repeatability.

Results:

The response of the detector was linear for 59 veterinary drug residues in extensive range (two to three orders of magnitude) with a high coefficient of determination (R2) (0.9995-0.9998). The limit of quantification (LOQ) ranged from 0.1μg/kg to 2.0μg/kg for 59 veterinary drug residues in pork samples. The repeatability was in the range of 1.0%-9.5%. Average recoveries of 59 veterinary drugs at three spiked levels ranged from 53.7%-117.8% with relative standard deviation (RSD) of 1.9%-13.9%. The full MS scan coupled with data-dependent MS/MS mode was applied for screening the target compounds to simultaneously obtain the accurate mass of parent ion and the mass spectrum of fragments. Elemental composition, accurate mass, and retention time and characteristic fragment ions were used to establish a homemade database.

Conclusion:

The ability of the homemade database was verified by analyzing the real pork samples, and the result was satisfactory.

An Easy Efficient Method of Veterinary Drug Residue Analysis in Raw Milk by RP-HPLC-UV with Application to Raw Milk

Background:

This study reports an easy method of a veterinary drug investigation in raw milk, based on QuECHERS extraction followed by RP-HPLC-UV analysis. Use of this benchtop system was motivated by its availability and moderate cost relatively to other sophisticated methods such as LC-MS which are more efficient.

Methods:

This developed method has been optimized and then after validation according to EU legislation, it demonstrated good linearity with R²>0.997, acceptable peak resolution within a short time (<9.5 min) and good recovery of the analyzed drugs (OXY, ALZ and IVR, respectively 87.08, 99.02 and 92.01 %). Additionally, we applied the method to the analysis of cow milk, collected in Nouakchott, capital of Mauritania.

Results:

The obtained results indicated a mixed level of drug use according to targeted molecules. In 42% of sampled farms, the anti-parasitics IVR and ALZ were detected whereas the antibiotic OXY was detected in 50%.

Conclusion:

This investigation shows that 17% of the sampled farms exceeded European standards for IVR drug.

The use of ultra-high-pressure-liquid-chromatography tandem time-of-flight mass spectrometry as a confirmatory method in drug residue analysis: Application to the determination of antibiotics in piglet liver

Consumption of food containing antibiotic residues can cause direct toxic effects, such as allergic reactions, or indirect effects, like the possibility to contribute to the development of antimicrobial resistance. It is essential for consumer food safety, as well as for public health, to monitor antibiotics in foods of animal origin intended for human consumption, particularly in piglets, a highly consumed meat in Portugal. Concerning the lack of regulations regarding the validation criteria for the ToF-MS (time-of-flight mass spectrometry) drug residues determination, this study presents an approach for the use of UHPLC (ultra-high-pressure-liquid-chromatography)-ToF-MS not only for screening but also for confirmatory purposes of 45 antibiotics from 7 different classes. Thus, a method was optimized and validated in accordance with Decision 2002/657/EC by evaluating CCα, CCβ, specificity, selectivity, recovery, ruggedness, repeatability and reproducibility. For antibiotics with no MRL set, the lowest values achieved for CCα and CCβ were, respectively, of 0.1 μg kg^-1 and 0.2 μg kg^-1 for cinoxacin. Regarding precision, the CV values obtained ranged from 5% to 21% for repeatability and from 6% to 22% for reproducibility. Recoveries were calculated falling between 82% and 120%. After validation, the method was used to analyse piglet liver samples. Antibiotic residues were determined in 47% of the 21 analysed samples. Nevertheless, all the antibiotics were detected at concentrations below the MRLs.

Simultaneous determination of multi-class antibiotics and steroid hormones drugs in livestock and poultry faeces using liquid chromatography-quadrupole time-of-flight mass spectrometry

A method for simultaneous determination of multi-class antibiotics and steroid hormone analysis in faeces of livestock and poultry was developed using liquid chromatography-quadrupole time-of-flight mass spectrometry (LC-QTOF MS). An in-house database was built for 156 detected drugs using Personal Compound Database Library software (PCDL) including compound name, monoisotopic mass, chemical formula, RT, chemical structure and three CID MS/MS spectra. The linearity result showed that all the drugs exhibited good linearity with determination coefficients (R²) higher than 0.99. The drug recoveries and their RSDs for all three faeces samples (pig, cattle and chicken) were tested and 81, 96 and 92 drugs were chosen for analysis in pig, cattle and chicken faeces, respectively. Further validation showed that 73 veterinary drugs in all three kinds of faeces samples can be quantified in one analytical run. This work shows that qualitative and quantitative analysis using LC-QTOF MS represents a simple, sensitive, low-cost and high-throughput methodology in routine laboratory analyses.

Human pharmaceutical and pesticide residues in Israeli dairy milk in association with dietary risk assessment

Throughout the world, more than six billion people consume milk and milk products yearly. The safety and quality of dairy milk are regularly monitored in most countries worldwide. The Israeli monitoring program of chemical residues in milk has not changed in the last decades, focusing only on major veterinary drugs and few selected environmental contaminants such as heavy metals and persistent organic pollutants. Consequently, a knowledge gap exists regarding the potential occurrence of other chemicals such as human pharmaceuticals and non-monitored pesticides in milk. In this survey, 51 commercial bovine and goat milk samples were analysed by LC-MS/MS and pharmaceutical and pesticide residues are reported in the range of 0.1-93 µg/L. Israeli milk samples revealed at least one and up to five chemical residues simultaneously. The pesticides found in milk were below the European maximum residue limit values. The risk assessment performed, indicated negligible risk.

Simultaneous Determination of Pesticides and Veterinary Pharmaceuticals in Environmental Water Samples by UHPLC–Quadrupole-Orbitrap HRMS Combined with On-Line Solid-Phase Extraction

Pesticides and veterinary pharmaceuticals are used for effective crop production and prevention of livestock diseases; these chemicals are released into the environment via various pathways. Although the chemicals are typically present in trace amounts post-release, they could disturb aquatic ecosystems and public health through resistance development toward drugs or diseases, e.g., reproductive disorders. Thus, the residues of pesticides and veterinary pharmaceuticals in the environment must be managed and monitored. To that end, we developed a simultaneous analysis method for 41 target chemicals in environmental water samples using ultra-high-performance liquid chromatography (UHPLC)–quadrupole-orbitrap high-resolution mass spectrometry (HRMS) coupled with an on-line solid-phase extraction system. Calibration curves for determining linearity were constructed for 10–750 ng∙L−1, and the coefficient of determination for each chemical exceeded 0.99. The method’s detection and quantitation limits were 0.32–1.72 ng∙L−1 and 1.02–5.47 ng∙L−1, respectively. The on-line solid-phase extraction system exhibited excellent method reproducibility and reduced experimental error. As the proposed method is applicable to the monitoring of pesticides and veterinary pharmaceuticals in surface water and groundwater samples acquired near agricultural areas, it allows for the management of chemicals released into the environment.

Suspect screening of plastic-related chemicals in northern pike (Esox lucius) from the St. Lawrence River, Canada

Environmental contaminant monitoring traditionally relies on targeted analysis, and very few tools are currently available to monitor "unexpected" or "unknown" compounds. In the present study, a non-targeted workflow (suspect screening) was developed to investigate plastic-related chemicals and other environmental contaminants in a top predator freshwater fish species, the northern pike, from the St. Lawrence River, Canada. Samples were extracted using sonication-assisted liquid extraction and analyzed by high performance liquid chromatography coupled with quadrupole time of flight mass spectrometry (HPLC-QTOF-MS). Ten bisphenol compounds were used to test the analytical performances of the method, and satisfactory results were obtained in terms of instrumental linearity (r² > 0.97), recoveries, (86.53-119.32%), inter-day precision and method detection limits. The non-targeted workflow data processing parameters were studied, and the peak height filters (peak filtering step) were found to influence significantly the capacity to detect and identify trace chemicals in pike muscle extracts. None of the ten bisphenol analogues were detected in pike extracts suggesting the absence of accumulation for these chemicals in pike muscle. However, the non-targeted workflow enabled the identification of diethyl phthalate (DEP) and perfluorooctanesulfonic acid (PFOS) in pike extracts. This approach thus can be also applied to various contaminants in other biological matrices and environmental samples.

Comparison of Solid-Phase Microextraction to Solvent Extraction and QuEChERS for Quantitative Analysis of Veterinary Drug Residues in Chicken and Beef Matrices

A fully automated high-throughput method using solid-phase microextraction (SPME) was developed and validated for quantitative analysis of more than 100 veterinary drugs in chicken and beef tissue. The work also encompassed a comparison of the SPME method to two well-documented sample preparation procedures, solvent extraction (SE) and quick, easy, cheap, effective, rugged, and safe (QuEChERS). SPME showed considerably less matrix effects, with only two compounds showing significant matrix effects in comparison to 30% of analytes in QuEChERS and 42% in SE in beef tissue. Excellent accuracy and precision results were achieved with all methods in the chicken matrix, with more than 91% of analytes falling within the 70-120% range of their true concentrations and relative standard deviation of ≤25% at 0.75X and 1.5X, where X is the maximum residue level. Similar results were achieved in beef tissue. All methods were able to meet regulatory limit of quantitation levels for the majority of target analytes.

Development of a liquid chromatography-quadrupole-time-of-flight-mass spectrometry based method for the targeted and suspect screening of contaminants in the pearl oyster Pinctada imbricata radiata

A rapid method based on solvent extraction followed by direct injection in liquid chromatography-quadrupole-time-of-flight-mass spectrometry (LC-Q-TOF-MS) was developed for the targeted and suspect screening of contaminants in the soft tissues of the pearl oyster Pinctada imbricata radiata. The quantification method was first validated for the targeted analysis of 21 contaminants including some pharmaceutically active compounds, with the relative recoveries ranging from 88 to 123%, and method detection limits generally below 1 ng g^-1 on the wet weight (ww) basis. This targeted analysis method was then applied to oyster samples collected around the Qatari coast between 2017/2018, and none of the 21 compounds were detected in these samples. The post-acquisition data treatment based on the accurate mass measurement in both full MS scan and All Ions MS/MS was further used for mining other contaminants in oyster extracts, as well as 21 targeted compounds spiked in oyster extracts (suspect screening). The 21 spiked compounds were identified successfully and the estimated limit of identification for the individual 21 compounds ranged from 0.5 to 117 ng g^-1 ww of oyster tissues. A phthalate, di(2-ethylhexyl) phthalate (DEHP) was identified to be present in oyster extracts from 2018 batches, at a concentration level significantly higher than that in procedure blanks. These results confirmed that high resolution MS data obtained using the targeted method can be exploited through suspect screening workflows to identify contaminants in the tissues of bioindicator mollusks. However, a number of false identifications could be obtained and future work will be on improving the success rate of the correct identifications using this workflow.

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.

Occurrences, levels and risk assessment studies of emerging pollutants (pharmaceuticals, perfluoroalkyl and endocrine disrupting compounds) in fish samples from Kalk Bay harbour, South Africa

A comprehensive analysis of 15 target chemical compounds (pharmaceuticals and personal care product, perfluoroalkyl compounds and industrial chemicals) were carried out to determine their concentrations in selected commercially exploited, wild caught small and medium sized pelagic fish species and their organs (Thyrsites atun (snoek), Sarda orientalis (bonito), Pachymetopon blochii (panga) and Pterogymnus laniarius (hottentot)) obtained from Kalk Bay harbour, Cape Town. Solid phase extraction (SPE) method based on Oasis HLB cartridges were used to concentrate and clean-up the samples. Liquid chromatography-mass spectrometry analysis of these chemical compounds revealed the simultaneous presence of at least 12 compounds in different parts of the selected fish species in nanogram-per-gram dry weight (ng/g dw) concentrations. The results revealed that perfluorodecanoic acid, perfluorononanoic acid and perfluoroheptanoic acid were the most predominant among the perfluorinated compounds and ranged between: (20.13-179.2 ng/g), (21.22-114.0 ng/g) and (40.06-138.3 ng/g). Also, diclofenac had the highest concentration in these edible fish species out of all the pharmaceuticals detected (range: 551.8-1812 ng/g). The risk assessment values were above 0.5 and 1.0 for acute and chronic risk respectively which shows that these chemicals have a high health risk to the pelagic fish, aquatic organisms and to humans who consume them. Therefore, there is an urgent need for a precautionary approach and the adequate regulation of the use and disposal of synthetic chemicals that persist in aquatic/marine environment in this province and other parts of South Africa, to prevent impacts on the sustainability of our marine environment, livelihood and lives.

A simple and high-throughput method for multiresidue and multiclass quantitation of antimicrobials in pangasius (Pangasionodon hypophthalmus) fillet by liquid chromatography coupled with tandem mass spectrometry

The development and validation of a throughput method for the determination of 25 antibacterial drugs (two β-lactams, eight quinolones, two macrolides, five sulfonamides, trimethoprim, four tetracyclines and three amphenicols) in pangasius fish muscle by LC-MS/MS were performed. A simple, efficient and fast extraction procedure was developed using acetonitrile and a 0.1 M EDTA solution as solvents for extraction. All compounds were determined in a single run, and chromatographic separation was achieved using a Zorbax SB C18 column with a mobile phase comprised of purified water +0.1% formic acid (A) and acetonitrile +0.1% formic acid (B) in a linear gradient program. The method was validated aαording to the requirements of European Decision 2002/657/EC. To quantify the analytes, matrix-matched analytical curves were constructed with spiked blank tissues and showed linearity (r²) higher than 0.99. For all analytes, the precision and accuracy were determined at the levels of 3 ng/g (low), 10 ng/g (low-middle), 50 ng/g (high-middle) and 100 ng/g (high). The precision (CV%) was lower than 18.6% and the accuracy (determined as recovery) was between 65% and 119%. The limit of quantitation was 3.0 ng/g, with the exception of chloramphenicol, which was 0.3 ng/g, and amoxicillin and doxycycline, which were 10 ng/g. The method was successfully applied to analyze pangasius muscle samples from Vietnam available at the Brazilian retail market, and 5 out of 40 samples showed the presence of low-residue levels of enrofloxacin and, consequently, must be considered out of conformity. It is recommended that competent authorities should avoid the commercialization of pangasius fillet contaminated with residues of this veterinary drug.

Optimization of the Data Treatment Steps of a Non-targeted LC-MS-Based Workflow for the Identification of Trace Chemical Residues in Honey

Non-targeted screening (e.g., suspected-target) is emerging as an attractive tool to investigate the occurrence of contaminants in food. The sample preparation and instrument analysis steps are known to influence the identification of analytes with non-targeted workflows, especially for complex matrices. However, for methods based on mass spectrometry, the impact of the post-analysis data treatment (e.g., feature extraction) on the capacity to correctly identify a contaminant at trace level is currently not well understood. The aim of the study was to investigate the influence of seven post-analysis data treatment parameters on the non-targeted identification of trace contaminants in honey using high-performance liquid chromatography coupled to hybrid quadrupole time-of-flight mass spectrometry (HPLC-QTOF-MS). Seven compounds reported as veterinary drugs for honeybees were applied as model compounds. Among the parameters studied, the expansion window for chromatogram extraction and the average scans included in the spectra influenced significantly the identification process results. The optimized data treatment was applied to the non-targeted screening of veterinary drugs, pesticides, and other contaminants in 55 honey samples as a proof of concept. Among the 43 compounds included in a library of honey-related compounds that was used for screening, eight compounds were tentatively identified in at least one honey sample. The tentative identity of two of these compounds (tylosin A and hydroxymethylfurfural) was further confirmed with analytical standards. Graphical Abstract.

Development and validation of a multi-residue and multi-class screening method of 44 antibiotics in salmon (Salmo salar) using ultra-high-performance liquid chromatography/time-of-flight mass spectrometry: Application to farmed salmon

A fast and sensitive multi-residue and multiclass screening method for the simultaneous determination of 44 antimicrobials in salmon muscle, using ultra- high-performance liquid chromatography/time-of-flight mass spectrometry (UHPLC-TOF/MS), was develop and validated. Two different procedures for the extraction step were tested, and an extraction with acetonitrile, ethylenediaminetetra acetic acid (EDTA) and n-hexane proved to be the best alternative. The method was validated, in accordance with Decision 2002/657/EC, using a qualitative approach at the CCβ level. The detection of the analytes was accomplished by retention time and accurate mass, whose maximum error should not exceed 5 ppm. All the compounds were successfully detected and identified at concentration levels corresponding to ½ maximum residue limit (MRL). The screening method was applied to 39 store bought samples of farmed salmon purchased in Portugal, originating from Norway and Denmark, and no antibiotic residues were detected.

SWATH-MS screening strategy for the determination of food dyes in spices by UHPLC-HRMS

A multi-class wide-scope screening method for the detection and identification of artificial colours and illegal dyes in spices was developed for regulatory purposes. The screening was carried out by ultra-high performance liquid chromatography hyphenated with a quadrupole/time-of-flight mass spectrometry (UHPLC-QTOF-MS) with sequential window acquisition of all theoretical fragment-ion spectra (SWATH) and was validated with forty-one compounds by spiking experiments in curry and paprika extracts. In order to detect and identify the compounds with a high level of confidence, a home-made tandem mass spectrometry (QTOF-MS/MS) database of approximately one hundred illegal dyes and artificial colours was created. The procedure was then used to screen field samples of spices and spice blends purchased from Swiss markets. Sudan IV, Sudan I, bixin (E160b) and Ponceau 4R (E124) were all detected among the eight non-compliant samples.

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.

Surface plasmon resonance based sensor for the detection of glycopeptide antibiotics in milk using rationally designed nanoMIPs

Glycopeptide antibiotics are known as the last resort for the treatment of serious infections caused by Gram-positive bacteria. The use of milk products contaminated with these antibiotic residues leads to allergic reactions and sensitivity in human. Also, long-term consumption of milk products containing low levels of these antibiotics may cause the relevant bacteria to build up resistance to these last resort antibiotics. Sensitive, rapid and effective quantification and monitoring systems play a key role for their determination in milk products. Hence, molecularly imprinted nanostructures were rationally designed in this work to produce high affinity synthetic receptors to be coupled with a surface plasmon resonance sensor for the analysis of glycopeptide antibiotics in milk samples. The nanoMIP-SPR sensor enabled vancomycin quantification with the LODs of 4.1 ng mL⁻¹ and 17.7 ng mL⁻¹ using direct and competitive assays, respectively. The recoveries rates for two sensor methods ranged in 85–110% with RSDs below 7%. The affinity between the nanoMIP receptors and the target molecule (dissociation constant: 1.8 × 10⁻⁹ M) is mostly superior to natural receptors and other synthetic receptors. Unlike other methods commonly employed for the detection of milk contaminants this approach is extremely simple, fast and robust, and do not require pre-sample treatment.

Quick Multi-Class Determination of Residues of Antimicrobial Veterinary Drugs in Animal Muscle by LC-MS/MS

On the basis of the highly sensitive and selective liquid chromatography-tandem mass spectrometry technique, a generic extraction solvent and a sample dilution method was developed for the residue analysis of different polar veterinary drugs known as fluoroquinolones, sulfonamides, macrolides, and tiamulin in chicken muscle. The results showed that the matrix-matched calibration curves of all 10 compounds were in an effective linear relationship (r² ≥ 0.997) in the range of 0.2⁻100 μg L^-1. At three spiking levels of 2 (5), 50, and 100 μg kg^-1, average recoveries of analytes were between 67.1% and 96.6% with relative standard deviations of intra-day and inter-day below 20%. The limits of detection and limits of quantification of the method were in the range of 0.3⁻2.0 μg kg^-1 and 2.0⁻5.0 μg kg^-1, respectively, which were significantly lower than their maximum residue limits. In addition, the intensity of the target analytes and its corresponding matrix effects were obviously related to the sample dilution times (matrix concentration). There were no significant differences (p > 0.05) in the average content of almost any of the analytes in medicated chickens between this method and the method in the literature for determining analytes. Lastly, the proposed method was successfully applied for the simultaneous analysis of 10 common veterinary drugs in food animal muscle tissues.