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Solid phase extraction (SPE) using traditional column materials offers several advantages, but its ability to simultaneously extract and purify commonly used veterinary drugs, such as chloramphenicol, malachite green, leuco-malachite green and semi-carbazone, remains unproven.Therefore, in the present study, a rapid analytical method based on ultrasound-assisted SPE combined with colloidal gold test strips was developed and applied herein to determine the residues of these veterinary drugs in common aquatic products. Under optimized conditions, the method achieved a limit of detection in the range of 0.01-0.5 μg/kg, inter-day RSDs of the spiked samples in the ranges of 0.99-5.58 % and 1.6-7.2 %, and absolute recoveries in the range of 84.2-112.9 % using the colloidal gold immunoassay and enzyme-linked immunosorbent assay methods, respectively. The SPE column efficiently enriched the four veterinary drugs simultaneously, showing considerable potential for determining common veterinary drug residues in aquatic products., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Co-extraction of multiple types of target substances is the key to achieve high throughput detection. In this work, PDA@MOF-808/PAN NFsM was prepared by co-modified polyacrylonitrile nanofiber membrane (PAN NFsM) with polydopamine (PDA) and metal-organic framework-808 (MOF-808), and its potential as a solid-phase extraction (SPE) adsorbent was investigated by using the most typical nine veterinary drug residues in eggs and chicken as model target substances. The results show that PDA@MOF-808/PAN NFsM could effectively co-extract all the target substances (adsorption efficiency ranged from 81.46 % to 96.78 %), and had good capability of sample matrix purification (matrix effect was lower than -15.26 %), so a new SPE method has been established. Combined with UPLC-MS/MS, the detection limits were 0.3 to 3.1 μg/kg, the recoveries were between 71.02 % and 106.48 %, and the relative standard deviations were lower than 12.03 %, indicating that the method has considerable good sensitivity, accuracy and precision., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

A modified QuEChERS method was developed to determine multi-class pesticide and veterinary residues in aquatic products. Chitosan microspheres were conveniently synthesized and utilized as the cleanup adsorbent in the QuEChERS procedure, showcasing rapid filtration one-step pretreatment ability for the determination of drug multi-residues in aquatic products. Compared to conventional synthetic sorbents, chitosan microspheres not only have good purification performance, but also have renewable and degradable properties. This novel sorbent worked well in the simultaneous determination of 95 pesticides and veterinary drug residues in aquatic products after being combined with an improved one-step vortex oscillating cleanup method. We achieved recoveries ranging from 64.0% to 115.9% for target drugs in shrimp and fish matrix. The limits of detection and quantification were 0.5-1.0 and 1.0-2.0 μg kg -1 , respectively. Notably, hydrocortisone was detected with considerable frequency and concentration in the tested samples, underscoring the necessity for stringent monitoring of this compound in aquatic products., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024. Published by Elsevier Ltd.)

Based on salting-out assisted liquid-liquid extraction (SALLE) and high performance liquid chromatography tandem mass spectrometry (HPLC-MS/MS), a simple, rapid pretreatment without complex clean-up for the determination of 22 veterinary drug residues in aquatic products was developed and validated. In order to improve the efficiency of the method, the key procedural parameters of SALLE were fabricated. Na 2 EDTA-Mcllvaine buffer/ACN was used as the extraction solvent, anhydrous MgSO 4 and NaCl as the extraction salts. The relationship between extraction efficiency and logD was initially evaluated during the optimization process. This study was well validated in various aquatic samples such as bass, large yellow croaker, carp, and shrimp, the limits of detection (LOD) and accuracy for all compounds ranged from 0.5 to 1.0 μg/kg, 71.4% to 120%. This method has the advantages of rapidity, simplicity, low cost, and high efficiency, and has broad potential for risk monitoring and evaluation of veterinary antibiotics in aquatic products., Competing Interests: Declaration of competing interest The authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Veterinary drugs play a crucial role in the treatment of various animal diseases. However, their residues, stemming from issues, such as withdrawal period lapses, overuse, or abuse, can jeopardize food safety and human health. This study addresses recent regulations in Korea concerning specific veterinary drugs (anacolin, ephedrine, menichlopholan, piperonyl butoxide, and etisazole HCl) and their ongoing discussions. This study aimed to validate two pre-developed methods for quantifying residues in livestock and fishery products using QuEChERS and liquid chromatography-tandem mass spectrometry. Both methods exhibited excellent linearity, recoveries (70.3-119%), and coefficient of variations (1.3-28%), along with low limits of detection and quantification (0.3-4 ng/g and 1-12 ng/g). This study is significant for its contribution to the detection of veterinary drugs in livestock and fishery products, given the limited research available on the methods for analyzing these substances., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

Effective monitoring of veterinary drug residues in food is essential for legislation compliance and food safety, yet remains challenging due to low concentrations and complex matrices. This study introduced a miniaturized 96-well electromembrane extraction (EME) technique for pre-concentration and isolation 80 prohibited/restricted veterinary drugs from honey samples. Three liquid membranes were developed and characterized: V1 ("V" for veterinary), a mixture of 2-undecanone and 0.5 % 2-nitro-p-cymene, was optimal for extraction of quinolones, tetracyclines, and β-agonists. V2, a mixture of 2-nitrophenyl octyl ether and a deep eutectic solution (formed upon mixing 6-methylcoumarin with thymol in a 1:1 w/w ratio) in a 1:1 v/v ratio, with the addition of 0.5 % di(2-ethylhexyl) phosphate (DEHP), was suitable for macrolides and sulfonamides extraction. V3, a deep eutectic solvent formed upon 1-decanoic acid and camphor in a 1:1 w/w ratio with 1 % DEHP, was suitable for aminoglycosides and β-lactams. Operational parameters were fine-tuned to achieve optimal extraction efficiencies, with recoveries ranging from 20.1-117.5 %, 20.3-91.9 %, and 20.1-118.8 % for V1, V2, and V3, respectively. High precision was observed for compounds with recoveries over 40 % (intra-day: 0.4-27.7 %; inter-day: 2.6-33.0 %), and matrix effects were generally within 80-120 %. This work established a theoretical framework for EME in food analysis, highlighting its potential as a powerful sample pretreatment method for the detection of veterinary drug residues. The results demonstrated the feasibility and advantages of using EME for ensuring food safety and regulatory compliance., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

The complicated food matrix seriously limits the one-time test for the potential food hazards in non-targeted analysis. Accordingly, developing advanced sample pretreatment strategy to reduce matrix effects is of great significance. Herein, newly-integrated hollow-structured covalent organic frameworks (HCOFs) with large internal adsorption capacity and target-matched pore size were synthesized via etching the core-shell structured COFs. The as-prepared HCOFs could be directly applied for matrix clean-up of vegetable samples, while further modification of polydopamine (PDA) network facilitated application for animal samples. Both HCOFs and HCOFs@PDA with the comparable sizes to the matrix interference gave excellent adsorption performance to targets, achieving satisfied recoveries (70%-120%) toward 90 pesticides and 44 veterinary drugs in one-test, respectively. This work showed the great potential of the facile-integrated HCOFs with high stability and customized size to remove interference matrix and offered a universal strategy to achieve simultaneous screening of hazards with considerable quantity in high-throughput non-targeted analysis., Competing Interests: Declaration of competing interest The authors declare the following financial interests/personal relationships which may be considered as potential competing interests: Jing-Min Liu reports financial support was provided by National Key Research and Development Program of China. If there are other authors, they declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

An HPLC-MS/MS multi-class method for quantitation of 15 different classes of veterinary drug residues (>140 analytes) in milk and poultry feed was developed and validated. Accuracy criteria for routine laboratories were met for the majority of analytes, > 83 % in milk and between 50 and 60 % in chicken feed, with an apparent recovery of 60-140 %. Extraction efficiency criteria were met for >95 % of the analytes for milk and > 80 % for chicken feed. Intermediate precision meets the SANTE criterion of RSD < 20 % for 80-90 % of the analytes in both matrices. For all analytes with an existing MRL in milk, the LOQ was below the related MRL. Twenty-nine samples of commercial milk and chicken feed were analyzed within the interlaboratory comparison. No residues of veterinary drugs were found in the milk samples. However, the feed samples exhibited high levels of nicarbazin, salinomycin, and decoquinate., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 The Authors. Published by Elsevier Ltd.. All rights reserved.)

A 15-channel pressure filtration purification method was presented for high throughput sample preparation of aquatic products. A cost-effective device was constructed and melamine sponge was selected as the cleanup sorbent. Upon interfacing with HPLC-MS/MS, the analytical procedure demonstrated its suitability for quantifying 160 pesticides and veterinary drug residues in aquatic products such as fish, shrimp, and crab. The method achieved sample recoveries ranging from 61.3 to 124.9 %. The detection limits were established between 0.5 and 1.0 μg/kg, while the quantitation limits were confirmed to be within the range of 1.0-2.0 μg/kg. The method was applied to quantify the pesticide and veterinary drug residues in mostly consumed aquatic products from five coastal provinces in China. The results showed significant differences between different aquatic products in the concentrations of pesticide and veterinary drug residues, implying the necessity of supervision for the accurate determination of pesticides and veterinary drugs., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2024 Elsevier Ltd. All rights reserved.)

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., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023 Elsevier Ltd. All rights reserved.)

The use of veterinary drugs (VDs) is widely administered to animals for both therapeutic and prophylactic purposes. However, their improper use may involve their occurrence in the final products intended for human consumption. In this scientific work, a method for the investigation of target (n = 30) VDs residues and retrospective suspect screening followed by confirmation using analytical standards of others 38 contaminants in ready-to-eat cooked ham by ultra-high performance liquid chromatography coupled with high-resolution mass spectrometry (UHPLC-Q-Orbitrap HRMS) was developed. The extraction was performed based on the QuEChERS approach and validated in accordance with the European Regulation 2021/808. The application of the in-house validated method to ready-to-eat cooked ham showed the occurrence of fourteen VDs residues. Despite the important incidence, the concentration levels found were below the maximum residue limits set for VDs in porcine muscle, except for colchicine. Constant monitoring of animals derived food is strongly recommended to ensure the food safety of consumers., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

This work aimed to develop an integrated high-throughput screening and quantification for multi-class veterinary drug residues by HPLC-Q-Orbitrap mass spectrometry. A qualitative screening mass database of 171 veterinary drugs was created using full scanning mode, which improved the screening accuracy and scope. Beef and chicken samples were chosen to validate the quantification method at three spiked concentration levels. The quantification method of 146 veterinary drug residues was developed. After enzymatic hydrolysis, beef and chicken samples were treated using optimized QuEChERS. The calibration curves showed good linearities with correlation coefficients of 0.9921-0.9994. The recovery rates were within 52.1-138.2 % with relative standard deviations 0.4-17.7 %. The limits of detection and limits of quantification were in the range of 0.15-3.03 μg/kg and 0.5-10 μg/kg, respectively. The proposed method was demonstrated to be reliable for the simultaneous analysis of multi-class veterinary drugs. It is of significance to expand the screening scope and quantitative analysis efficiency., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

Veterinary drugs are widely used to improve the health and growth of livestock. The supervision of these residues is necessary to ensure food safety. A high-throughput method based on Oasis PRiME HLB with solid phase extraction for simultaneous qualitative and quantitative analysis of 155 veterinary drugs in livestock foods was developed by the ultra-high performance liquid chromatography tandem quadrupole linear-ion-trap mass spectrometry (UHPLC-QTRAP-MS). The limits of detection and quantification ranged from 0.5 μg/kg to 5 μg/kg and 2 μg/kg to 20 μg/kg, respectively. For over 85% of the analytes, the recoveries were between 60% and 120%. The positive simulated samples perfectly matched with a purity fit value over 70% from the self-built library. The screening results of UHPLC-QTRAP-MS were almost consistent with UHPLC tandem quadrupole-exactive orbitrap mass spectrometry (UHPLC-Q-Exactive Orbitrap/MS). The evaluated UHPLC-QTRAP-MS method was powerful and reliable for the screening and quantification of veterinary drugs in real samples., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

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/Fe 3 O 4 ) 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., (Copyright © 2022 Elsevier Ltd. All rights reserved.)

The practice of abusing antibiotics to improve livestock growth poses a threat to food safety. To prevent and regulate this, accurate monitoring of residual veterinary drugs (VDs) is required. A method based on QuEChERS with dispersive solid-phase extraction for the determination of multi-class VDs was investigated using selected product ions under optimized multiple reaction monitoring conditions. During the clean-up procedure, chitosan, octadecyl silica, primary-secondary amine, and enhanced matrix removal (EMR)-lipid were evaluated for simultaneous analysis of multi-class VDs in beef matrix. The EMR sorbent was most advantageous (113/115) compared to others, and showed a satisfactory recovery range (70.7-117.9%) except cefquinome (67.3%) and cefalonium (69.8%). This methodology can be used to detect oxolinic acid and ractopamine (27.4% and 88.0% of maximum residue limit, respectively) in real beef samples. We thus study propose a simple and fast analytical method for multi-class VDs for the future health of humans and animals., (Copyright © 2022 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Herein, an analytical method was developed for simultaneous determination of 12 anthelmintics (closantel, niclosamide, nitroxynil, rafoxanide, cymiazole, fluazuron, levamisole, morantel, praziquantel, pyrantel, thiophanate, and trichlorfon) in fishery products (eel, flatfish, and shrimp) using liquid-liquid extraction coupled with liquid chromatography-tandem mass spectrometry. A reversed-phase analytical column was then used to separate the analytes from various matrices. Linear matrix-matched calibration curves were generated with coefficients of determination ≥ 0.9935. Recovery rates at three spiking levels (5, 10, and 20 µg/kg) ranged between 61.58% and 119.37% with relative standard deviations ≤ 19.05%. Limits of detection were in the range of 0.3-1.6 μg/kg, whereas limits of quantification ranged between 1.0 and 5.0 μg/kg. The matrix effect was moderate with values ranging from -99.47% to 51.98%. Matrices procured from large markets tested negative for the 12 anthelmintics. The developed method proved amenable to real sample testing and can be used for simultaneous determination of target analytes in aquatic products., (Copyright © 2021 Elsevier Ltd. All rights reserved.)

A multi-residue method has been developed for the identification and quantification of 78 compounds from seven different classes of veterinary drugs in eggs. This method was based on dispersive solid phase extraction where mixed-mode cation exchange sorbent was used to combine the isolation of compounds and sample purification. The analysis was performed using ultra-high performance liquid chromatography-tandem mass spectrometry, and the chromatographic run time of one injection was 9.5 min. The mean recovery ranged from 70.5% to 119.2% and inter-day relative standard deviation was less than 17.0%. The limit of quantification ranged between 0.1 and 1 μg/kg, which was sufficient to support surveillance monitoring. Lastly, the method was successfully used to detect residues of veterinary drug in real samples. The dietary exposure risk was subsequently assessed using the results of the survey, indicating that the evaluated daily intake and percentage of acceptable daily intake were at toxicologically acceptable levels., Competing Interests: Declaration of Competing Interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2020 Elsevier Ltd. All rights reserved.)

A multi-class screening method for the determination of veterinary drugs and pesticides in eggs was developed by high performance liquid chromatography quadrupole-time-of-flight mass spectrometry (HPLC-QTOF-MS). A single-injection workflow was developed for qualitative analysis, and method validation was conducted in terms of retention time deviation (ΔRt), exact mass error (Δm), selectivity, specificity, precision and trueness. The characteristic fragment ions in information dependent acquisition (IDA) mode were summarized for retrospective and non-target screening. Five of 70 samples were found positive with sulfachloropyridazine, sulfamonomethoxine and fipronil sulfone. Compared with triple-quadrupole (QqQ) MS method, the obtained results showed that QTOF-MS gave comparable results to QqQ-MS with residue concentrations higher than 10 μg·kg -1 , whereas QqQ-MS was more powerful at lower concentrations (<1 μg·kg -1 ). Moreover, the amount of fragment ions acquired by HPLC-QTOF-MS decreased substantially at trace levels, which may be a potential cause of reduced reliability of identification., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

It is still a challenge to solve the matrix interferences in veterinary drug residue analysis. In this study, we reported a thin layer chromatography (TLC)-high-performance liquid chromatography (HPLC) method for determining total florfenicol (FF) residues, expressed as florfenicol amine (FFA), in porcine edible tissues. The tissue homogenate were acid-hydrolyzed to liberate the bound residues and convert them into FFA. The hydrolysates were washed with ethyl acetate and subsequently extracted with ethyl acetate under alkaline conditions. The supernatants were concentrated through evaporation, defatted with hexane, purified by TLC and analyzed by HPLC at 225 nm. The optimal developing solvent for TLC purification was ethyl acetate-acetone-ammonium hydroxide mixtures (2:8:0.5, v/v/v). The method was fully validated according to decision 2002/657/EC, and could be used for the routine monitoring of FF residues in pig. TLC showed excellent purification efficiency, and was expected to solve the matrix interferences in veterinary drug residue analysis., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

A generic extraction and UHPLC-Q-Orbitrap™-HRMS method was developed for four insect species (mealworm, grasshopper, house cricket and black soldier fly) analyzing a large spectrum of organic chemical contaminants, including pesticides (n = 25), (veterinary) drugs (n = 29), and mycotoxins (n = 23). To prove the method as 'fit-for-purpose', a successful validation was performed, both qualitatively, by determining the screening detection limit (SDL), selectivity and specificity, as well as semi-quantitatively, by assessing the within-day precision (relative standard deviation (RSD)) and recovery. For both the mealworm, grasshopper, house cricket and black soldier fly, 64, 61, 59 and 62 compounds were detected at the respective SDL levels (1-100 μg kg -1 ), predominantly below existing maximum residue limits for other edible matrices. Mean recoveries ranged between 70% and 120% and RSD-values were in line with European regulations (CD 2002/657/EC; SANCO). Finally, the potential of the screening methodology was demonstrated on real insect samples, revealing minor to no contamination., (Copyright © 2019 Elsevier Ltd. All rights reserved.)

A modified QuEChERS (Quick, Easy, Cheap, Effective, Rugged and Safe) method was developed for the simultaneous determination of veterinary drugs, pesticides and mycotoxins in eggs by ultrahigh-pressure liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). Several extraction conditions were tested and optimized, and the obtained extraction efficiency of all the targeted compounds (particularly macrolides) could fulfill the requirements. In the purification procedure, magnetic multiwalled carbon nanotubes (Fe 3 O 4 -MWCNTs) were used as adsorbents, and an external magnet was utilized to achieve a faster adsorbent separation, compared to the traditional centrifugation process. The recoveries of all analytes were in the range of 60.5%-114.6% at three fortified levels with relative standard deviations (RSDs) of less than 20%, and the LOQs ranged from 0.1 μg·kg -1 to 17.3 μg·kg -1 . This method was successfully applied to the analysis of egg samples, demonstrating its applicability and suitability for the routine analysis of multiclass residues in egg samples., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

There is an increasing concern about the negative impacts of veterinary drugs in beehive compartments. This study evaluates the presence and distribution of chemical residues in beeswax, bee bread and honey and determinates in what extension honeybees are exposed to them. Samples were analyzed by LC-MS/MS and GC-MS/MS with a wide scope of 322 chemical residues. Samples were collected from apiaries located in rural and forest areas, showing no difference in contamination of phytosanitary applications. Residues of acaricides used for sanitary treatments, coumaphos and two transformation products of amitraz (DMF and DMPF), were quantified at higher levels in wax and bee bread than in honey in most cases. Coumaphos, DMF and DMPF were detected in honey in the range 6-36 µg.kg -1 ; 45-541 µg.kg -1 ; 15-107 µg.kg -1 , respectively. All, except one sample, were below the EU MRLs, 396/2005 Regulation. Other pesticide residues were detected in beeswax and bee bread at various levels., (Copyright © 2018 The Authors. Published by Elsevier Ltd.. All rights reserved.)

Two extraction strategies for albendazole, chloramphenicol, trimethoprim, enrofloxacin, oxitetracycline and nicarbazin in egg were optimized for its quantitation by liquid chromatography. First, two designs were built to find out the optimized condition for the air assisted-dispersive liquid-liquid microextraction based on solidification of organic drop: a fractional factorial and a central composite design. The optimum conditions were 1140µL of water, 125mg of ZnSO 4 , 1175µL of acetonitrile, 1200µL of methyl alcohol and 740µL of propanone, using 1.00g of homogenized egg and 50µL of 1-dodecanol. Second, two designs were also built to optimize the dispersive liquid-liquid microextraction: a central composite design and a mixture design to set the combination of the re-suspended solvents. The optimum conditions were 1840μL of acetonitrile and 160μL of dichloromethane and the re-suspended mixture consisting in acetonitrile and sodium phosphate buffer 10mmolL -1 pH = 3.50 (30:70v/v)., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

This paper reports a unified sample preparation approach for high-throughput multi-residue analysis of veterinary drugs and pesticides in a single sub-sample of bovine milk. The sample (5 g) was deproteinized with acetonitrile before an aliquot (I) was withdrawn, and the remainder was phase-separated using MgSO 4 and NaCl. The acetonitrile layer (II) was recovered and the extracts combined, cleaned, and solvent-exchanged before the concentrations of veterinary drugs and pesticides were measured by ultra-fast liquid chromatography tandem mass spectrometry (UFLC-MS/MS). As a unique approach, extract II was analyzed simultaneously using gas chromatography tandem mass spectrometry (GC-MS/MS). Method performance for 78 drugs and 238 pesticides complied with CD 2002/657/EC and SANTE/11813/2017 guidelines, respectively, with significant savings in time and cost. Thus, it would be ideal for regulatory analysis of analytes ranging from non-polar organochlorine pesticides to polar drugs, including penicillins, quinolones, and tetracyclines., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

The aim of this work was to develop a simple and rapid analytical method for the simultaneous determination of a wide range of drug residues in milk by UHPLC-MS/MS. A total of 25 typical veterinary drugs investigated belong to six families including β-lactams, quinolones, β-agonists, phenicols, glucocorticoids and nitrofurans. The samples were extracted by acetonitrile and defatted with n-hexane twice. Electrospray ionization and positive/negative polarity switching were utilized for the analysis of 25 veterinary drugs in a single chromatographic run. The linearity, recovery, precision and matrix effects of the method were fully validated. The intra- and inter-precision were in the range of 1.7-11.1% and 2.5-10.4%, respectively. The average recoveries ranged from 65.9% to 123.5% with RSD less than 10.8% at three concentration levels. The proposed method was demonstrated to be simple, economical and reliable for the fast monitoring of these drug residues in milk samples., (Copyright © 2018 Elsevier Ltd. All rights reserved.)

This study investigated the thermal degradation of a veterinary drug, chloramphenicol, in model solutions (water), as well as in spiked and incurred mussel tissues to understand its fate in the food supply chain. Thermal degradation kinetics followed a first-order model in water (e.g. degradation rate: 0.0018-0.0025 min -1 at 100 °C). After 1 h at 100 °C, the percentage degradation in spiked tissues (28.1 ± 7.1%) was significantly different (p < .05) from the values in water (14.2 ± 1.6%) and incurred mussel tissues (19.0 ± 4.1%). Using liquid chromatography coupled to high-resolution accurate mass tandem mass spectrometry, the resulting degradation products of chloramphenicol were identified in water, spiked and incurred tissues, and were all different. Therefore, although the use of water models and spiking food samples may provide some information, our data confirm that "incurred models" should be systematically implemented to provide reliable information about veterinary drug residue stability for food safety risk assessments., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

In this study a simple and fast multi-class method for the determination of veterinary drugs in bovine liver, kidney and muscle was developed. The method employed acetonitrile for extraction followed by clean-up with EMR-Lipid® sorbent and trichloracetic acid. Tests indicated that the use of TCA was most effective when added in the final step of the clean-up procedure instead of during extraction. Different sorbents were tested and optimized using central composite design and the analytes determined by ultra-high-performance liquid chromatographic-tandem mass spectrometry (UHPLC-MS/MS). The method was validated according the European Commission Decision 2002/657 presenting satisfactory results for 69 veterinary drugs in bovine liver and 68 compounds in bovine muscle and kidney. The method was applied in real samples and in proficiency tests and proved to be adequate for routine analysis. Residues of abamectin, doramectin, eprinomectin and ivermectin were found in samples of bovine muscle and only ivermectin in bovine liver., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

In this work, a sensitive method based on nanoflow liquid chromatography high-resolution mass spectrometry has been developed for the multiresidue determination of veterinary drugs residues in honey, veal muscle, egg and milk. Salting-out supported liquid extraction was employed as sample treatment for milk, veal muscle and egg, while a modified QuEChERS procedure was used in honey. The enhancement of sensitivity provided by the nanoflow LC system also allowed the implementation of high dilution factors as high as 100:1. For all matrices tested, matrix effects were negligible starting from a dilution factor of 100, enabling, thus, the use of external standard calibration instead of matrix-matched calibration of each sample, and the subsequent increase of laboratory throughput. At spiked levels as low as 0.1 or 1 µg kg -1 before the 1:100 dilution, the obtained signals were still significantly higher than the instrumental limit of quantitation (S/N 10)., (Copyright © 2017 Elsevier Ltd. All rights reserved.)

The aim of this study was to develop an analytical method for the analysis of a wide range of veterinary drugs in honey and royal jelly. A modified sample preparation procedure based on the quick, easy, cheap, effective, rugged and safe (QuEChERS) method was developed, followed by liquid chromatography tandem mass spectrometry determination. Use of the single sample preparation method for analysis of 42 veterinary drugs becomes more valuable because honey and royal jelly belong to completely different complex matrices. Another main advantage of the proposed method is its ability to identify and quantify 42 veterinary drugs with higher sensitivity than reference methods of China. This work has shown that the reported method was demonstrated to be convenient and reliable for the quick monitoring of veterinary drugs in honey and royal jelly samples., (Copyright © 2016 Elsevier Ltd. All rights reserved.)

In this present study, we developed a simple, rapid and specific method for the quantitative analysis of the contents of amoxicillin (AMO), AMO metabolites and ampicillin (AMP) in eggs. This method uses a simple liquid-liquid extraction with acetonitrile followed by liquid chromatography-tandem mass spectrometry (LC-MS/MS). The optimized method has been validated according to requirements defined by the European Union and Food and Drug Administration. Extraction recoveries of the target compounds from the egg at 5, 10 and 25 μg/kg were all higher than 80%, with relative standard deviations not exceeding 10.00%. The limits of quantification in eggs were below the maximum residue limits (MRLs). The decision limits (CCα) ranged between 11.1 and 11.5 μg/kg, while detection capabilities (CCβ) from 12.1 to 13.0 μg/kg. These values were very close to the corresponding MRLs. Finally, the new approach was successfully verified for the quantitative determination of these analytes in 40 commercial eggs from local supermarkets., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

A sensitive, confirmatory ultra-high performance liquid chromatography-tandem mass spectrometric method was developed and validated to detect 23 veterinary drugs and metabolites (nitroimidazoles, benzimidazoles, and chloramphenicol components) in bovine milk. Compounds of interest were sequentially extracted from milk with acetonitrile and basified acetonitrile using sodium chloride to induce liquid-liquid partition. The extract was purified on a mixed mode solid-phase extraction cartridge. Using rapid polarity switching in electrospray ionization, a single injection was capable of detecting both positively and negatively charged analytes in a 9 min chromatography run time. Recoveries based on matrix-matched calibrations and isotope labeled internal standards for milk ranged from 51.7% to 101.8%. The detection limits and quantitation limits of the analytical method were found to be within the range of 2-20 ng/kg and 5-50 ng/kg, respectively. The recommended method is simple, specific, and reliable for the routine monitoring of nitroimidazoles, benzimidazoles, and chloramphenicol components in bovine milk samples., (Copyright © 2015 Elsevier Ltd. All rights reserved.)

This report presents a UPLC-MS/MS method for determination of mequindox (MEQ), quinocetone (QCT) and their 11 metabolites in chicken and pork samples. Following extraction process with acetonitrile-ethyl acetate, acidulation, and re-extraction with ethyl acetate in turn, target analytes were further purified using C18 solid phase extraction (SPE) cartridges for UPLC-MS/MS analysis. Validation was processed with mean recoveries from 69.1% to 113.3% with intra-day relative standard deviation (RSD) <14.7%, inter-day RSD <19.2%, and limit of detection between 0.05 and 1.0 μg/kg for each analytes. The verified method was successfully applied to the quantitative determination of commercial samples. This developed procedure will help to control food animal products with MEQ and QCT residues, and facilitate further pharmacokinetic and residue studies of similar quinoxaline-1,4-dioxide veterinary drugs., (Copyright © 2014 Elsevier Ltd. All rights reserved.)

Net analyte signal standard addition method has been used for the simultaneous determination of sulphadiazine and trimethoprim by spectrophotometry in some bovine milk and veterinary medicines. The method combines the advantages of standard addition method with the net analyte signal concept which enables the extraction of information concerning a certain analyte from spectra of multi-component mixtures. This method has some advantages such as the use of a full spectrum realisation, therefore it does not require calibration and prediction step and only a few measurements require for the determination. Cloud point extraction based on the phenomenon of solubilisation used for extraction of sulphadiazine and trimethoprim in bovine milk. It is based on the induction of micellar organised media by using Triton X-100 as an extraction solvent. At the optimum conditions, the norm of NAS vectors increased linearly with concentrations in the range of 1.0-150.0 μmolL(-1) for both sulphadiazine and trimethoprim. The limits of detection (LOD) for sulphadiazine and trimethoprim were 0.86 and 0.92 μmolL(-1), respectively., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

Dispersive liquid-liquid microextraction (DLLME) was coupled with field-amplified sample stacking in capillary electrophoresis (FASS) for the determination of five non-steroidal anti-inflammatory drugs (NSAIDs) in bovine milk and dairy products. After extraction, the enriched analytes were back-extracted into a basic aqueous solution for injection into CE. Under optimum conditions, enrichment factors were in the range 46-229. Limits of detection of the analytes ranged from 3.0 to 13.1 μg kg(-1) for all matrices analysed. Calibration graphs showed good linearity with coefficients of determination (R(2))≥ 0.9915 and relative standard deviations (RSD%) of the analyses in the range of 0.6-6.2% (n=5). Recoveries of all NSAIDs from bottled milk, raw milk, yogurt and white cheese samples were in the ranges of 86.6-109.3%, 84.3-100.5%, 77.4-107.3%, and 90.9-101.6%, respectively. DLLME-FASS-CE was demonstrated to be a rapid and convenient method for the determination of NSAIDs in milk and dairy products., (Copyright © 2012 Elsevier Ltd. All rights reserved.)

A rapid, simple and generic analytical method which was able to simultaneously determine 220 undesirable chemical residues in infant formula had been developed. The method comprised of extraction with acetonitrile, clean-up by low temperature and water precipitation, and analysis by ultra performance liquid chromatography coupled with electrospray ionization tandem mass spectrometry (UPLC-ESI-MS-MS) using multiple reaction monitoring (MRM) mode. Most fat materials in acetonitrile extract were eliminated by low temperature clean-up. The water precipitation, providing a necessary and supplementary cleanup, could avoid losses of hydrophobic analytes (avermectins, ionophores). Average recoveries for spiked infant formula were in the range from 57% to 147% with associated RSD values between 1% and 28%. For over 80% of the analytes, the recoveries were between 70% and 120% with RSD values in the range of 1-15%. The limits of quantification (LOQs) were from 0.01 to 5 μg/kg, which were usually sufficient to verify the compliance of products with legal tolerances. Application of this method in routine monitoring programs would imply a drastic reduction of both effort and time., (Copyright © 2012 Elsevier Ltd. All rights reserved.)