Wide-scope analysis of veterinary drug and pesticide residues in animal feed by liquid chromatography coupled to quadrupole-time-of-flight mass spectrometry

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.

Multiresidue method for the simultaneous analysis of antibiotics and mycotoxins in feeds by ultra-high performance liquid chromatography coupled to tandem mass spectrometry

Residues in animal feeds and foods of animal origin have been important safety issue concerning both human and animal health. A multiresidue method for determination of eight mycotoxins and ten antibiotics was developed and validated in animal feeds by using QuEChERS (quick, easy, cheap, effective, rugged, and safe) extraction followed by UHPLC-MS/MS. Optimisation of UHPLC-MS/MS parameters was performed to achieve good separation and resolution. The method was validated according to the European Commission Decision 2002/657/EC. Matrix matched calibration curves showed good r2 (≥0.995) values, and limit of quantification (LOQ) values varied between 1.2 and 5.2 μg kg−1. Average recoveries ranged from 60 to 102% with relative standard deviations of 2.2 and 15.6% for all type of feed samples except for tetracyclines, lincomycin, tylosin, ochratoxin A, and fumonisin (B1 and B2).

Determination of Florfenicol, Thiamfenicol and Chloramfenicol at Trace Levels in Animal Feed by HPLC⁻MS/MS

Administration of florfenicol and thiamfenicol through medicated feed is permitted within the European Union, always following veterinary prescription and respecting the withdrawal periods. However, the presence of low levels of florfenicol, thiamfenicol, and chloramfenicol in non-target feed is prohibited. Since cross-contamination can occur during the production of medicated feed and according to Annex II of the European Regulation 2019/4/EC, the control of residue levels of florfenicol and thiamfenicol in non-target feed should be monitored and avoided. Based on all the above, a sensitive and reliable method using liquid chromatography tandem mass spectrometry was developed for the simultaneous detection of chloramfenicol, florfenicol, and thiamfenicol at trace levels in animal feed. Analytes were extracted from minced feed with ethyl acetate. Then, the ethyl acetate was evaporated, the residue was resuspended in Milli-Q water and the extract filtered. The method was in-house validated at carryover levels, with concentration ranging from 100 to 1000 µg/kg. The validation was conducted following the European Commission Decision 2002/657/EC and all performance characteristics were successfully satisfied. The capability of the method to detect amfenicols at lower levels than any prior perspective regulation literature guarantees its applicability in official control activities. The developed method has been applied to non-compliant feed samples with satisfactory results.

Analyzing multiple pesticides in tobacco leaf using gas chromatography with quadrupole time-of-flight mass spectrometry

A method combining gas chromatography with quadrupole time-of-flight mass spectrometry has been developed for the simultaneous analysis of multiple pesticide residues in tobacco leaf. The retention index and high accurate masses of ions from the first-stage and the second-stage mass spectra of each pesticide were collected for qualitation and quantification. A total of 115 pesticides were evaluated. The extract from organic tobacco leaf was used as a model matrix. The limit of detection was <10 ng/mL, and the limit of quantification was in the range of 1-20 ng/mL for 95% of the tested pesticides. The correlation coefficients were >0.9900 for all tested pesticides. At three concentrations (10, 50, and 100 ng/mL), most compounds presented satisfactory recoveries ranging from 70 to 120% and good precision <20%. Finally, three tobacco leaf samples collected from a local market were analyzed. A total of three pesticides were found, including dimethachlon, triadimenol, and flumetralin. Each pesticide was confirmed by the presence of three ions at the expected retention index and mass. In conclusion, gas chromatography with quadrupole time-of-flight mass spectrometry appears to be one of the most efficient tools for the analysis of pesticide residues in tobacco leaf.

Metabolomics, Nutrition, and Potential Biomarkers of Food Quality, Intake, and Health Status

Diet, dietary patterns, and other environmental factors such as exposure to toxins are playing an important role in the prevention/development of many diseases, like obesity, type 2 diabetes, and consequently on the health status of individuals. A major challenge nowadays is to identify novel biomarkers to detect as early as possible metabolic dysfunction and to predict evolution of health status in order to refine nutritional advices to specific population groups. Omics technologies such as genomics, transcriptomics, proteomics, and metabolomics coupled with statistical and bioinformatics tools have already shown great potential in this research field even if so far only few biomarkers have been validated. For the past two decades, important analytical techniques have been developed to detect as many metabolites as possible in human biofluids such as urine, blood, and saliva. In the field of food science and nutrition, many studies have been carried out for food authenticity, quality, and safety, as well as for food processing. Furthermore, metabolomic investigations have been carried out to discover new early biomarkers of metabolic dysfunction and predictive biomarkers of developing pathologies (obesity, metabolic syndrome, type-2 diabetes, etc.). Great emphasis is also placed in the development of methodologies to identify and validate biomarkers of nutrients exposure.

Analysis of banned veterinary drugs and herbicide residues in shellfish by liquid chromatography-tandem mass spectrometry (LC/MS/MS) and gas chromatography-tandem mass spectrometry (GC/MS/MS)

Seafood safety is a crucial public health concern for consumers. In this study, we applied a validated method to analyze the residue of banned veterinary drugs in shellfish, namely chloramphenicol, malachite green, leucomalachite green, and nitrofuran metabolites; additionally, the QuEChERS method was employed to detect 76 herbicides by LC/MS/MS and GC/MS/MS. In total, 42 shellfish samples, which included hard clams, freshwater clams, and oysters, were collected from aquafarms and production areas in Taiwan during 2012. Our results revealed 3.8ng/g of chloramphenicol in one hard clam, 19.9-32.1ng/g of ametryn in two hard clams, 16.1-60.1ng/g of pendimethalin in four hard clams, and 17.0ng/g of mefenacet in one oyster, indicating that 19.1% of the samples contained residues from banned veterinary drugs and pesticides. These data can be used to monitor the residue of veterinary drugs and pesticides in aquatic organisms and as a reference for food safety.

A Confirmatory Method Based on HPLC-MS/MS for the Detection and Quantification of Residue of Tetracyclines in Nonmedicated Feed

The Commission Regulation 574/2011/EC set up maximum levels of coccidiostats and histomonostats in nonmedicated feed as a consequence of carry-over during manufacturing. Carry-over takes place from medicated to nonmedicated feed during feed production. Similar contamination could also occur for other pharmaceuticals such as tetracyclines, a group of antibiotics commonly employed in food production animal. The objective of this work is to present a simple and fast method for the simultaneous detection of four tetracyclines (chlortetracycline, doxycycline, oxytetracycline, and tetracycline) in nontarget feed at a μg/kg level. Validation of the method was performed according to the guideline included in the Commission Decision 2002/657/EC for official method. The validated method was successfully applied to 50 feed samples collected from different milk farms and 25 samples obtained from feed manufacturers. While oxytetracycline was the tetracycline most frequently detected, chlortetracycline was the analyte measured at the highest concentration 15.14 mg/Kg. From 75 nonmedicated feed analysed 15% resulted to be positive for the presence of one tetracycline.

Development and validation of rapid multiresidue and multi-class analysis for antibiotics and anthelmintics in feed by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry

A new multi-residue method for the analysis of veterinary drugs, namely amoxicillin, chlortetracycline, colistins A and B, doxycycline, fenbendazole, flubendazole, ivermectin, lincomycin, oxytetracycline, sulfadiazine, tiamulin, tilmicosin and trimethoprim, was developed and validated for feed. After acidic extraction, the samples were centrifuged, purified by SPE and analysed by ultra-high-performance liquid chromatography coupled to tandem mass spectrometry. Quantitative validation was done in accordance with the guidelines laid down in European Commission Decision 2002/657/CE. Matrix-matched calibration with internal standards was used to reduce matrix effects. The target level was set at the authorised carryover level (1%) and validation levels were set at 0.5%, 1% and 1.5%. Method performances were evaluated by the following parameters: linearity (0.986 < R(2) < 0.999), precision (repeatability < 12.4% and reproducibility < 14.0%), accuracy (89% < recovery < 107%), sensitivity, decision limit (CCα), detection capability (CCβ), selectivity and expanded measurement uncertainty (k = 2).This method has been used successfully for three years for routine monitoring of antibiotic residues in feeds during which period 20% of samples were found to exceed the 1% authorised carryover limit and were deemed non-compliant.

Analysis of Tetracyclines in Medicated Feed for Food Animal Production by HPLC-MS/MS

The use of medicated feed is a common practice in animal food production to improve animal health. Tetracyclines and β-Lactams are the groups that are most frequently added to this type of feed. The measurement of the concentration of the analytes in these types of samples is sometimes due to the matrix characteristic, and manufacturers are demanding fast, precise and reproducible methods. A rapid confirmatory method based on a simple extraction protocol using acidified methanol and followed by high performance liquid chromatography coupled to a tandem mass spectrometer for the quantification of four tetracyclines in feed is presented. Validation was performed following the guidelines of Decision 2002/657/EC. Results indicated that the four tetracyclines can be identified and quantified in a concentration range between 50 and 500 mg/kg with recoveries between 84% and 109% and RSD for precision under reproducible conditions between 12% and 16%. Satisfactory results were also obtained with interlaboratory studies and by comparing the method with an HPLC-Fluorescent method.

Wide-Scope Screening of Illegal Adulterants in Dietary and Herbal Supplements via Rapid Polarity-Switching and Multistage Accurate Mass Confirmation Using an LC-IT/TOF Hybrid Instrument

A new analytical strategy was developed that integrates a generic sample preparation into a liquid chromatography-multistage ion trap/time-of-flight mass spectrometry (LC-IT(MS(n))/TOF), allowing for large-scale screening and qualitative confirmation of wide-scope illegal adulterants in different food matrices. Samples were pretreated by a fast single-tube multifunction extraction for accurate multistage mass measurement on the hybrid LC-IT/TOF system. A qualitative validation performed for over 500 analyte-matrix pairs showed the method can reduce most of the matrix effects and achieve a lower limit of confirmation at 0.1 mg/kg for 73% of the target compounds. A unique combination of dual-polarity detection, retention time, isotopic profile, and accurate MS(n) spectra enables more comprehensive and precise confirmation, based on the multiparameter matching by automated library searching against the user-created database. Finally, the applicability of this LC-IT(MS(n))/TOF-based screening procedure for discriminating coeluting isobars, identifying nontarget adulterants, and even tentatively elucidating unexpected species in real samples is demonstrated.

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

A wide-scope screening methodology has been developed for the identification of veterinary drugs and pharmaceuticals in fish tissue and milk using ultrahigh-performance liquid chromatography quadrupole time-of-flight mass spectrometry (UHPLC-QTOF MS). The method was validated using a qualitative approach at two concentration levels. The detection of the residues was accomplished by retention time, accurate mass, and the isotopic fit using an in-house database. Product-ion spectra were used for unequivocal identification of the compounds. Generic sample treatment was applied. The majority of the compounds were successfully detected and identified at concentration levels of 150 ng mL(-1) in milk and 200 μg kg(-1) in fish (>80% of the compounds in both matrices), whereas satisfactory results were also obtained at concentration levels of 15 ng mL(-1) in milk and 20 μg kg(-1) in fish (>60% of the compounds detected and identified).

Analysis of veterinary drug and pesticide residues in animal feed by high-resolution mass spectrometry: comparison between time-of-flight and Orbitrap

The use of medium-high-resolution mass spectrometers (M-HRMS) provides many advantages in multi-residue analysis. A comparison between two mass spectrometers, medium-resolution (MRMS) time-of-flight (TOF) and high-resolution (HRMS) Orbitrap, has been carried out for the analysis of toxic compounds in animal feed. More than 300 compounds belonging to several classes of veterinary drugs (VDs) and pesticides have been determined in different animal feed samples using a generic extraction method. The use of a clean-up procedure has been evaluated in both instruments, and several validation parameters have been established, such as the matrix effect, linearity, recovery and sensitivity. Finally, both instruments have been used during the analysis of 18 different feed samples (including chicken, hen, rabbit and horse). Some VDs (sulfadiazine, trimethoprim, robenidine and monensin sodium) and one pesticide (chlorpyrifos) have been identified. In general, better results were obtained using the Orbitrap, such as sensitivity (1-12.5 µg kg(-1)) and recovery values (60-125%). Moreover, this analyser had several software tools, which reduced the time for data processing and were easy to use, performing quick screening for more than 450 compounds in less than 5 min. However, some disadvantages such as the high cost and a decrease in the number of detected compounds at low concentrations must be taken into account.

Screening of pesticides and polycyclic aromatic hydrocarbons in feeds and fish tissues by gas chromatography coupled to high-resolution mass spectrometry using atmospheric pressure chemical ionization

This paper reports a wide-scope screening for detection and identification of pesticides and polycyclic aromatic hydrocarbons (PAHs) in feeds and fish tissues. QuEChERS sample treatment was applied, using freezing as an additional cleanup. Analysis was carried out by gas chromatography coupled to hybrid quadrupole time-of-flight mass spectrometry with atmospheric pressure chemical ionization (GC-(APCI) QTOF MS). The qualitative validation was performed for over 133 representative pesticides and 24 PAHs at 0.01 and 0.05 mg/kg. Subsequent application of the screening method to aquaculture samples made it possible to detect several compounds from the target list, such as chlorpyrifos-methyl, pirimiphos-methyl, and ethoxyquin, among others. Light PAHs (≤4 rings) were found in both animal and vegetable samples. The reliable identification of the compounds was supported by accurate mass measurements and the presence of at least two representative m/z ions in the spectrum together with the retention time of the peak, in agreement with the reference standard. Additionally, the search was widened to include other pesticides for which standards were not available, thanks to the expected presence of the protonated molecule and/or molecular ion in the APCI spectra. This could allow the detection and tentative identification of other pesticides different from those included in the validated target list.

Wide-scope analysis of pesticide and veterinary drug residues in meat matrices by high resolution MS: detection and identification using Exactive-Orbitrap

A multiresidue and multiclass method for the simultaneous determination of more than 350 compounds including pesticides, biopesticides and veterinary drugs in different meat matrices (beef, pork and chicken) by ultra-high performance liquid chromatography coupled to Orbitrap MS has been developed. In the present study, the determination of fragments was accomplished as an essential tool for a reliable identification of compounds using high resolution MS. To obtain these fragments, different strategies have been carried out in order to ensure an appropriate fragment assignment and identification. The analytical method is suitable for qualitative analysis, and it was also evaluated for quantitative analysis. Generic extraction conditions were optimized, obtaining adequate recovery and precision values for most of the studied analytes (>290). The limits of detection ranged from 2 to 16 µg kg(-1). Limits of quantification were 10 µg kg(-1) with the exception of few compounds with a higher value (50 or 100 µg kg(-1)). Limits of identification were also established, and they ranged from 2 to 150 µg kg(-1). This method was applied to the analysis of 18 meat samples and some veterinary drugs as enrofloxacin and sulfadiazine were detected and further identified/quantified (with triple quadrupole) in two different samples at 33 µg kg(-1) and trace levels, respectively. No pesticides were detected in the analyzed samples.