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Purpose In cataract surgery, viscoelastics protect the corneal endothelium against phacoenergetic and mechanical damage and ensure anterior chamber stability. Vital dyes (trypan blue) are effective aids in anterior segment surgery, especially in challenging cases, but may lead to cytotoxic reactions depending on concentration and dose. A complete removal of the dye is therefore of great importance. Recently, a new viscoelastic colored with Trypan blue (Pe-Ha-Blue®PLUS) was introduced to increase the safety of ophthalmological procedures. The aim of the present work was to determine the residual amount of the dye Trypan Blue that remains on a slide during the routine application of two commercial products (Trypan Blue dye Vision Blue® and Pe-Ha-Blue®PLUS) by Raman spectroscopy. Materials and methods For both products, a test sample (after application of the substance, the slides were flushed according to the clinical procedure) and a reference sample (the substances remained on the slide) were imaged using a Raman spectroscope (LabRam 800 HR spectrometer (Horiba Jobin Yvon GmbH, Bensheim, Germany)) and then analyzed. Results The remaining residues of the reference samples of both substances were clearly detected by the spectroscopy measurement. In the mean spectrum of the Vision Blue® test specimen, the Raman bands of Trypan blue were clearly visible at a Raman shift of 1200-1600 cm-1, indicating residues on the test specimen. The test sample of Pe-Ha-Blue®PLUS did not show any Raman bands in the typical Trypan blue Raman shift. Conclusions The results of our in-silico experiment showed that a drop of a combination of a vital dye with a viscoelastic could be washed-out more easily with BSS compared to a dye itself without viscoelastics. This suggests that at least in an in silico experiment the removal of both, the viscoelastics and the TB is easier compared to the removal of the TB alone. Further in-vitro experiment in pig cadaver eyes are planned to prove this washout effect. If this concept can be demonstrated, this could further increase the safety of dye-assisted ophthalmic procedures.

For the first time, this paper aimed to evaluate nine ionophore and synthetic coccidiostat residues in poultry muscle samples, obtained from different production types, by solid-liquid extraction followed by liquid chromatography with tandem mass spectrometry (LC-MS/MS). The fully validated methodology was successfully applied to a total of 101 chicken and turkey samples obtained from canteens, supermarkets, and home productions in Portugal. Halofuginone, diclazuril, decoquinate, narasin, lasalocid, and salinomycin were detected in 20.8% of the samples. Home raised samples showed a greater frequency, 47.1%. The synthetic coccidiostats halofuginone, diclazuril, and decoquinate were found in averages of 0.7 μg kg-1,2.9 μg kg-1, and 3.7 μg kg-1, respectively, while averages of 1.2 μg kg-1, 1.6 μg kg-1, and 1.3 μg kg-1 were found regarding the ionophores narasin, lasalocid, and salinomycin. As for the risk assessment, values lower than 8.06% of the acceptable daily intake (ADI) were observed, indicating that exposure to coccidiostats through consumption of poultry meat does not represent risk to consumers.

This manuscript describes a new multiresidue method utilising ultra-performance liquid chromatography tandem mass spectrometry (UPLC-MS/MS) via multiple reaction monitoring (MRM), for the identification and quantification of 58 antibiotics and their 26 metabolites, in various solid and liquid environmental matrices. The method was designed with a ‘one health’ approach in mind requiring multidisciplinary and multisectoral collaborative efforts. It enables comprehensive evaluation of antibiotic usage in surveyed communities via wastewater-based epidemiology, as well as allowing for the assessment of potential environmental impacts. The instrumental performance was very good, demonstrating linearity up to 3000 μg L−1, and high accuracy and precision. The method accuracy in several compounds was significantly improved by dividing calibration curves into separate ranges. This was accompanied by applying a weighting factor (1/x). Microwave-assisted and/or solid-phase extraction of analytes from liquid and solid matrices provided good recoveries for most compounds, with only a few analytes underperforming. Method quantification limits were determined as low as 0.017 ng L−1 in river water, 0.044 ng L−1 in wastewater, 0.008 ng g−1 in river sediment, and 0.009 ng g−1 in suspended solids. Overall, the method was successfully validated for the quantification of 64 analytes extracted from aqueous samples, and 45 from solids. The analytes that underperformed are considered on a semi-quantitative basis, including aminoglycosides and carbapenems. The method was applied to both solid and liquid environmental matrices, whereby several antibiotics and their metabolites were quantified. The most notable antibiotic-metabolite pairs are three sulfonamides and their N-acetyl metabolites; four macrolides/lincomycins and their N-desmethyl metabolites; and five quinolone metabolites. Graphical abstract

The occurrence, concentrations, and variables associated with tetracycline, polyether ionophore, and anthelmintic residues in the livers of chickens sold in the informal market in South Africa were determined. Ultrahigh-performance liquid chromatography-tandem mass spectrometry was used to simultaneously analyze for four tetracyclines, five polyether ionophores, and six anthelmintic residues. The study determined the presence of residues in liver samples at both the limit of quantifications (LOQ) and concentrations over the maximum residue limit (MRL), i.e., noncompliant. Doxycycline (tetracycline group) was detected in 24 (24.5%) of 98 chicken livers, and 15 (15.3%) of the 98 were noncompliant. Mean ± standard deviation (SD) concentrations of 919.04 ± 1,081.30 ppb (LOQ) and 1,410.57 ± 108.89 ppb (MRL) were obtained. Maduramicin was detected in 27 (27.6%) of 98 chicken livers, and 19 (19.4%) of 98 were noncompliant. The mean ± SD for LOQ was 117.96 ± 84.56 ppb, and MRL was 153.21 ± 76.29 ppb. The concentrations of residues of doxycycline and maduramicin in chicken livers varied significantly across townships. Lasalocid was found in 31 (31.6%) of 98 samples, of which 5 (5.1%) had concentrations above the MRL. The mean ± SD concentration of lasalocid was 62.90 ± 170.84 ppb for samples in which lasalocid was quantified and 310.16 ± 356.68 ppb for noncompliant samples. Detectable concentrations of praziquantel, closantel, and rafoxanide (anthelmintics) residues were found in 3 (3.1%), 1 (1.0%), and 2 (2.0%) of 98 chicken livers, respectively. The presence of residues of three classes of veterinary drugs in chicken livers poses food safety implications to consumers and indicates a need for enhanced regulatory enforcement in controlling these drugs in South Africa. HIGHLIGHTS

Chloramphenicols, nitroimidazoles, lincosamides, and macrolides are common antibiotics used in veterinary medicine. Overdoses of these drugs will lead to residual substances in animal-derived foods and accumulate in the body through the food chain, thereby exerting adverse effects on human health. Therefore, regulation of veterinary drug levels is imperative to ensure the quality of animal-derived foods and safeguard the health of consumers. In this study, a method based on ultra performance liquid chromatography-tandem mass spectrometry coupled with solid phase extraction (SPE-UPLC-MS/MS) was developed for the simultaneous determination of eight prohibited and restricted veterinary drugs and three metabolite residues across four categories (chloramphenicols, nitroimidazoles, lincosamides, and macrolides) in eggs, liquid milk, chicken, and freshwater fish. The main factors affecting the response, recovery, and sensitivity of the method, such as the type and pH values of the extraction solvent, dilution solution for the analytes, type of chromatographic column, and type and proportion of the mobile phase, were optimized during sample pretreatment and instrument analysis. The samples were hydrolyzed and dispersed in 0.1 mol/L phosphate buffer solutions (pH 9.0) and extracted with acetonitrile. The extract was further extracted using ethyl acetate. After centrifugation, the supernatant ethyl acetate was concentrated to near dryness in nitrogen below 40 ℃. The residue was dissolved in 0.3 mL methanol, followed by the addition of 5.7 mL phosphate buffer solution. After shaking, the solutions were purified and enriched on an Oasis HLB SPE column. The target analytes were separated on an ACQUITY UPLC BEH C18 chromatographic column (100 mm×2.1 mm, 1.7 μm) at a column temperature of 40 ℃ with a flow rate of 0.4 mL/min. The injection volume was 10 μL. Gradient elution was carried out with methanol and 0.1% formic acid aqueous solution as the mobile phases. Multiple reaction monitoring (MRM) was conducted in the positive and negative electrospray ionization modes. The isotope internal standard method was used for quantitative analysis. Under optimal conditions, each analyte showed a good linear relationship in each range, and the correlation coefficient (R2) was greater than 0.99. The limits of detection (LODs) ranged from 0.050 to 0.50 μg/kg, and the limits of quantification (LOQs) ranged from 0.20 to 1.5 μg/kg. With eggs, freshwater fish, chicken, and liquid milk as the matrix samples, the recoveries in spiked blank samples were determined at different addition levels in compliance with the current legislation. The average recoveries of the 11 analytes were 65.3% to 108%. The relative standard deviations (RSDs) were between 0.40% and 21%. The matrix effects of the analytes were between 0.0124% and 46.80% in four different samples after purification on the Oasis HLB column. The practicality of the proposed approach for routine analyses of the eight prohibited and restricted veterinary drugs, and three metabolite residuals was evaluated by applying it to the determination of these compounds in animal-derived food samples. The samples, including 80 eggs, 80 chicken, 40 liquid milk, and 32 freshwater fish, were procured from a supermarket and a farm product market. The results of the positive samples were consistent with those observed with the standard methods. The method described herein is easy to operate, sensitive, and accurate. It is suitable for the simultaneous and rapid determination of various prohibited and restricted veterinary drug residues and metabolites in animal-derived foods.

Moxidectin (MXD), an antiparasitic drug, is effective for a variety of external and internal parasites in companion and farm animals. This study aimed to calculate the withdrawal period by investigating the residue depletion of MXD in swine edible tissues after pouring at the dosage of 2.5 mg/kg B.W. The concentrations of MXD in swine edible tissues were determined by a modified preparation procedure based on HPLC-FLD. The method was validated giving LOD and LOQ of 0.5 μg/kg and 1 μg/kg respectively with measured recoveries ranging from 62.9%-89.2% at three different concentrations and a precision (RSD) of less or equal to 15.7%. The muscle, liver, kidney and fat tissues were collected at 0.5, 5, 10, 20, 25 d after administration. The results showed that fat was the target tissue with the highest concentration for MXD. The withdrawal period was 26 days for the MRL of 500 μg/kg in fat. The results provide fundamental information to ensure food safety and establishment of a rational medication regimen.

Residues of veterinary drugs in poultry meat have serious health effects on humans (e.g., antimicrobial resistance, carcinogenicity, and hypersensitivity), which make the control of veterinary drug residues an important parameter in ensuring consumer protection. This work was performed to quantitatively determine two co-formulated anti-infective veterinary agents, tylosin tartrate (TYT) and doxycycline hydrochloride (DOX) in different tissues of broiler chickens (liver, muscles, and fat) using high performance liquid chromatography. The chicken was treated with the recommended dose of a binary mixture of the drugs (Tydovet). Moreover, the study aimed to estimate the withdrawal time of both drugs in chicken tissues. The analysis was done by solvent extraction and solid-phase extraction for clean-up of samples from the tissue matrix, followed by liquid chromatographic determination of the cited drugs with UV-detection. Residue decline with time was tracked, and both antibiotics were found to be more persistent in liver tissues than other tissues (muscle and fat). The effect of freezing and cooking was investigated on tissue residue levels. While freezing had little effect on the concentration of both antibiotics; cooking, as anticipated, led to a marked decline. Therefore, it is recommended to pay attention to the proper withdrawal periods before marketing to ensure the hygienic suitability of broilers edibles for safe human consumption. PRACTICAL APPLICATION: This novel study measures tylosin and doxycycline residues simultaneously in different tissues (muscle, fat, and liver) after administration of Tydovet powder to the broiler chicken. Residues in fat persisted for a longer time than in muscle in case of TYT, whereas the reverse was noticed in DOX.

Ion mobility spectrometry (IMS) is an analytical separation and diagnostic technique that is simple and sensitive and a rapid response and low-priced technique for detecting trace levels of chemical compounds in different matrices. Chemical agents and environmental contaminants are successfully detected by IMS and have been recently considered to employ in food safety. In addition, IMS uses stand-alone or coupled analytical diagnostic tools with chromatographic and spectroscopic methods. Scientific publications show that IMS has been applied 21% in the pharmaceutical industry, 9% in environmental studies and 13% in quality control and food safety. Nevertheless, applications of IMS in food safety and quality analysis have not been adequately explored. This review presents the IMS-related analysis and focuses on the application of IMS in food safety and quality. This review presents the important topics including detection of traces of chemicals, rate of food spoilage and freshness, food adulteration and authenticity as well as natural toxins, pesticides, herbicides, fungicides, veterinary, and growth promoter drug residues. Further, persistent organic pollutants (POPs), acrylamide, polycyclic aromatic hydrocarbon (PAH), biogenic amines, nitrosamine, furfural, phenolic compounds, heavy metals, food packaging materials, melamine, and food additives were also examined for the first time. Therefore, it is logical to predict that the application of the IMS technique in food safety, food quality, and contaminant analysis will be impressively increased in the future. HighlightsCurrent status of IMS for residues and contaminant detection in food safety.To assess all the detected contaminants in food safety, for the first time.Identified IMS-related parameters and chemical compounds in food safety control.

In Brazil, the buffalo milk market has been growing. However, identity and quality standards have not been established for this raw material, nor have proper distinctions between buffalo milk and bovine milk been defined. Currently, the State of Rio Grande do Sul (RS) has only three producers that supply raw material for officially marketed derivatives. The aim of this study was to determine the identity and quality standards of raw buffalo milk in this region. Samples were obtained biweekly from three farm cooling tanks between June 2017 and August 2018, to reach a total of 69 samples. The averages for the results of the physicochemical parameters fat, protein, lactose, total solids, SNF (solids-not-fat), calcium, density, FP, acidity and SCC were 5.5 g/100 g, 4.06 g/100 g, 5.07 g/100 g, 15.5 g/100 g, 9.96 g/100 g, 0.161 g/100 g, 1.034 g/ml, −0.527°C, 16°D and 95 × 103 cells/ml, respectively. With reference to the microbiological parameters, the mean of the Standard Plate Count (SPC) and thermotolerant coliforms were 9,0 × 104 CFU/ml and 1.6 × 102 MPN/ml, respectively. Regarding coagulase-positive staphylococci, 36 samples tested positive (52% of total). Neither Salmonella spp. nor Listeria monocytogenes, nor antibiotic or antiparasitic residues were detected in any sample. In conclusion, the buffalo milk used as raw material for dairy products in southern Brazil demonstrated satisfactory physicochemical and microbiological characteristics, in accordance with recent scientific literature.

A novel, sensitive and rapid high performance liquid chromatography (HPLC) method for the determination of ceftiofur by pre-column derivatization with 1,2-naphthoquinone-4-sulfonate. Analysis was performed within 5 min on a Kinetex C18 column based on core-shell technology. The mobile phase composed of acetonitrile-water (50:50, v/v) pumped isocratically at a flow rate of 1.0 mL/min under UV detection at 254 nm. The factors affecting the derivatization reaction and separation conditions were carefully evaluated and optimized. The method was linear over the concentration range of 45–450 ng/mL with a limit of detection of 3.29 ng/mL and limit of quantitation of 10.97 ng/mL. The new method was successfully applied for the analysis of ceftiofur in the veterinary formulation and honey with average recoveries of 100.78% and 98. 83%, respectively. The present method is suitable and favorable for the analysis of ceftiofur on account of its sensitivity, rapidity and cost-effectiveness. In addition, it could have significant application for the determination of ceftiofur in other food products.

A simplified method is described for reducing the analysis time of nitrofurans (NFs) and nitrofuran metabolites (NFMs) in the aquatic animals. Most existing HPLC-MS/MS methods are intended only for NFMs and are based on their fast metabolic transformations. We optimized a method for simultaneously detecting major NFs and their metabolites, including nitrovin (NV) that imply use of an optimized buffer solution. The novel method was validated by six different aquatic animal matrices (loach, catfish, shrimp, lobster, scallop, and eel) spiked with the analytes at 0.5, 1.0, and 2.0 μg kg−1. Recovery rates and %RSDs (relative standard deviations) of 82–97% and 1–8% were observed for NFMs, respectively, with values of 70–96% and 1–8% obtained for furazolidone, furaltadone, nitrofurazone, nitrofurantoin, and NV, respectively. Linearity was observed in the 0.1–20 μg L−1 range, with correlation coefficients greater than 0.99 recorded for all compounds. The developed method is sensitive, accurate, easier to use, and faster than previous methods when applied to real samples. To the best of our knowledge, this is the first method that can simultaneously determine NFs and their metabolites, as well as NV, using a single-step extraction process.

An analytical method for the determination of six emerging derivatives or metabolites together with 25 common macrolides antibiotics in milk by ultra-performance liquid chromatography quadrupole/electrostaticfield orbitrap mass spectrometry was established. The samples were purified with optimized Quick, Easy, Cheap, Effective, Rugged, Safe methods. The amounts of primary-secondary amine, C18, and sodium acetate adsorbent materials were optimized by response surface method to obtain the best purification effect. The chromatographic separation was carried out using the XBridge-C18 (2.1 × 100 mm, 3.5 µm, Waters) column with mobile phase of acetonitrile with 0.1% v/v formic acid-water solutions (containing 10 mmol/L ammonium acetate), separated by gradient elution. The instrument was operated in the detection mode of electrospray positive and negative ions with Full MS/data dependent MS2 acquisition mode detection, external standard method was used for quantitative analysis. The limits of detection and limits of quantitation of 31 compounds were 0.1-0.5 µg/L and 0.5-2.0 µg/L, respectively. A total of 31 compounds performed a good linearity in the range of 1 to 200 µg/L, and the correlation coefficient was greater than 0.990. The spiked recoveries in milk samples were 81.07-110.1% and the relative standard deviation was less than 5.1%. The method was successful applied to actual sample testing in the market.

Iron composite nanoparticles were prepared (90% yield) using macromolecule chitosan and characterized by spectroscopic techniques (FT-IR, XRD, SEM, TEM & EDX). These were utilized to remove diclofenac sodium in water. The adjusted parameters were 400 μg/ L, 50.0 min., 5.0, 2.0 g/ L and 25.0 °C as concentration, contact time, pH, adsorbent amount and temperature for the elimination of diclofenac sodium in water with maximum 85% elimination. The sorption was spontaneous with exothermic. Data followed Langmuir, Temkin and Dubinin-Radushkevich models. Thermodynamic parameter ΔG° values were −12.19, −13.74 and −15.67 kJ/mol at 20, 25 and 30 °C temperatures. The values of ΔH° and ΔS° were 8.58 and 20.84 kJ/mol. Pseudo-first-order and liquid film diffusion mechanisms were proposed for the adsorption. This adsorption method is fast, effective eco-friendly and low-cost as it may be used in natural circumstances of water resources. The sorption method may be applied for the elimination of diclofenac sodium in any water body at a huge and financial scale.

An environmentally friendly method for the determination of testosterone and methyltestosterone by acid–base-induced deep eutectic solvents liquid–liquid microextraction (DES-ABLLME) combining with high-performance liquid chromatography was established. The deep eutectic solvent (DES) consisting of menthol:lauric acid:decanoic acid (3:1:1) can act as both hydrogen bond donor and hydrogen bond acceptor. In this approach, ammonia solution (NH3•H2O) is used as an emulsifier to react with DESs in the extraction process to generate salt and form milky white solution, achieving high extraction efficiency. Hydrochloric acid was used as a phase separator to change the emulsification state and promote the separation of extraction agent from water phase. A series of parameters were optimized including the volume of DES and the emulsifying agent, glucose concentration as well as hydrochloric acid volume. The method was linear in the range 0.5–100 μg mL−1 with a correlation coefficient (R) of 0.9999, and the limits of detection were 0.067 and 0.2 μg mL−1 for testosterone and methyltestosterone, respectively. This method was applied to analyze testosterone and methyltestosterone in milk samples, and the recoveries were between 89.2 and 108.2%.

The study aimed to evaluate the effects of heat on macrocyclic lactone residues in cows' milk. Ivermectin, abamectin, doramectin, eprinomectin and moxidectin were added to raw milk in three concentrations. The milk was then pasteurised (40 seconds at 74°C or 1 minute at 80°C) and boiled (10 minutes at 100°C). The analyses were performed with a validated method: LC-MS/MS. Thermal treatment resulted in a statistically significant decrease in the abamectin, eprinomectin, and moxidectin concentrations in the milk; however, the residues did not completely degrade. Boiling resulted in a greater decrease in the moxidectin concentrations than was observed with pasteurisation. The high pasteurisation and boiling processes had a greater effect on the eprinomectin residues than did the low pasteurisation process. The pasteurisation and boiling processes did not have an effect on the doramectin and ivermectin. The study concluded that the macrocyclic lactones are generally resistant to such processes.

It is often difficult to compare studies examining the effects of endectocides on dung fauna because of different experimental approaches, for example, active ingredients (eprinomectin, doramectin, ivermectin, moxidectin) and formulations (injectable, pour-on, spiked). To gain a better understanding, we performed a quantitative meta-analysis using 22 studies to assess the overall effect of endectocide residues on the occurrence (presence or absence) and abundance of aphodiine dung beetles. Our results document a positive effect on the occurrence of adult beetles, indicating that adults tend to be attracted to dung with residues. Conversely, larvae are less likely to occur in the presence of residues. Thus, either adults that colonize dung with residues do not lay eggs or, more likely, the larvae that hatch from these eggs die early in development. Abundance of adult and larval stages was shown to be significantly reduced in dung containing residues. When individual endectocides were compared, only ivermectin demonstrated a significantly negative effect on the abundance of both adults and larvae, possibly owing to a small sample size for other agents. In laboratory studies, only dung "spiked" with endectocides reduced the abundance of larvae, whereas during field research, only pour-on applications were shown to reduce the abundance of larvae. The present study further documents the nontarget effects of endectocide residues on dung-dwelling organisms, provides robust evidence on the consequences of different application methods, and emphasizes the need for standardized methodological techniques in future studies. Environ Toxicol Chem 2020;39:863-872. © 2020 SETAC.

International audience; A liquid chromatography with tandem mass spectrometry (LC-MS/MS) method was developed for the simultaneous quantification of residues of spiramycin, a macrolide antibiotic, and its active metabolite neospiramycin in cow's milk as well as in minor species milk, goat and ewe. Spiramycin-d3 was used as internal standard for quantification of both analytes. This analytical method was validated using a global accuracy profile as a graphical decision tool built according to the trueness and the precision of the method. A unique and optimal linear model with logarithm transformation (with a determination coefficient of 0.9991) allowed the measurement of both analytes in the milks of the three animal species, in a wide range from 0.2 to 10 times the Maximal Residue Limit (MRL) (40-2000 µg.kg(-1)). The limits of detection and quantification were 13 µg.kg(-1) and 40 µg.kg(-1), respectively. The accuracy profile was established to get 80% of future measurements in routine assays that will fall within the acceptance limits. Trueness of the method, expressed as relative bias, was comprised between -1.6% and 5.7% over the whole range of concentrations. The mean relative standard deviation for repeatability and intermediate precision were comprised between 1.1% and 2.7%; 2.5 and 4.2%, respectively, in all levels of concentration for the three milks. Moreover, a two-order polynomial function was used to model the relative expanded uncertainty with a determination coefficient of 0.834. This function aimed to determine the uncertainty of the future quantifications within the validated dosing range. Overall, the global accuracy profile highlighted the reliability of the method for the routine assays of spiramycin and neospiramycin even in milk from minor species (goat, ewe) by using the most accessible milk (often from cow), while guaranteeing a very high proportion of samples within the fixed acceptance limits. The applicability of this method was tested during a depletion study of spiramycin and neospiramycin in the milk of cow, goat and ewe. The developed analytical method will be useful to assess the distribution profile of the antibiotic and its metabolite in milk of minor species where few studies are available.

In this paper, dicyandiamide (Dd) and p-benzaldehyde (Bd) were heated at 180 °C for 3 h to prepare a new type of stable covalent organic framework (COF) DdBd nanosol with high catalysis. It was characterized by molecular spectroscopy and electron microscopy. The study found that DdBd had a strong catalytic effect on the new indicator reaction of polyethylene glycol 600 (PEG600)-chloroauric acid to form gold nanoparticles (AuNPs). AuNPs have strong resonance Rayleigh scattering (RRS) activity, and in the presence of Victoria Blue B (VBB) molecular probes, they also have a strong surface-enhanced Raman scattering (SERS) effect. Combined with a highly selective oxytetracycline (OTC) aptamer (Apt) reaction, new dual-mode scattering SERS/RRS methods were developed to quantitatively analyze ultratrace OTC. The linear range of RRS is 3.00 × 10−3 –6.00 × 10−2 nmol/L, the detection limit is 1.1 × 10−3 nmol/L, the linear range of SERS is 3.00 × 10−3–7.00 × 10−2 nmol/L, and the detection limit is 9.0 × 10−4 nmol/L. Using the SERS method to analyze OTC in soil samples, the relative standard deviation is 1.35–4.78%, and the recovery rate is 94.3–104.9%.

The simultaneous determination of multiple analytes has been an urgent demand in screening of antibiotic residues in food products of animal origin due to its higher analysis efficiency. Five aminoglycoside antibiotics (AGAs) have been monitored in milk, including gentamicin (GEN), kanamycin (KAN), neomycin (NEO), and streptomycin/dihydrostreptomycin (STR/diSTR). A chemiluminescence microarray immunoassay (CLMIA) based on nitrocellulose membrane had been developed for the detection of multiple AGAs, which the LODs for STR, KAN, NEO, and GEN were 4.74 ng/mL, 4.97 ng/mL, 2.99 ng/mL, and 4.42 ng/mL respectively. To improve the sensitivity of immunoassay, single-well carbon tubes (SWCNTs) were utilized as solid support for loading horseradish peroxidase-labelled goat anti-mouse antibody to obtain the multi-enzyme particles. After the optimization of usage of multi-enzyme particles and antibodies, the enhanced CLMIA was established and evaluated. The LODs were 1.25 ng/mL for STR, 0.64 ng/mL for KAN, 0.38 ng/mL for GEN, and 0.39 ng/mL for NEO, which was improved by threefold, sevenfold, 11-fold, and sevenfold compared with the conventional CLMIA developed. These methods presented higher specificity and repeatability. Finally, the enhanced CLMIA based on CNT-assisted multi-enzyme particles was utilized to analyze twenty-five milk samples from local market and dairy farm, which all the results were below the LOD. The enhanced CLMIA showed the great application potential for the detection of multiple targets simultaneously and provided efficient tool for the screening of pollutants in food.

This study established a rapid and reliable method to determine chloramphenicol (CAP), thiamphenicol (TAP) and florfenicol (FF) residues in Chinese gelatin medicines. CAP, TAP and FF were extracted from medicine samples using 2% (v/v) ammonium hydroxide in acetonitrile. Trypsin was used to eliminate the matrix effect caused by protein components in gelatin medicines, whereas anhydrous sodium sulfate, C18-N and NH2-PSA adsorbents were applied to reduce matrix effect induced by other components. The analytical method of these drugs was optimized on ultra high-performance liquid chromatography-mass spectrometer (UHPLC-MS/MS) through the analysis of their standard linearity and regression. The optimized extraction and analytical method were validated in one Chinese gelatin medicine sample (Colla corii asini, E Jiao) with three fortification levels (2, 5 and 10 μg/kg), and the recoveries of these drug residues ranged of 87.6–102.7%. The limit of detection and quantification of CAP, TAP and FF in the sample were 0.2 and 0.5 μg/kg, 0.4 and 1.5 μg/kg, and 0.5 and 1.5 μg/kg, respectively. A total of 30 Chinese gelatin medicine samples were analyzed using the established method. No drug residues were found in these samples except for one Testudinis Carapacis et Plastri (1.67 μg/kg FF) and one turtle shell glue (2.55 μg/kg FF).

By utilizing the coffee-ring effect and microfluidic paper-based analytical devices (µPADs), this study improved the sensitivity of the determination of norfloxacin in four different food matrices. Micro-PADs in this study were fabricated by designing and embedding wax channels onto cellulose-based filter paper through printing and subjecting the paper to heat to allow the wax to penetrate the paper. Determination of norfloxacin concentration in food samples was achieved by monitoring the colorimetric reaction that occurred between norfloxacin and the added iron (III) nitrate nonahydrate in 5 mM ammonia in each reaction chamber. A transition metal hydroxide was formed through this reaction that resulted in the formation of a solid precipitate to enable the antibiotic to bind to the iron molecule via coordination chemistry. This metal ion-antibiotic complex generated a visible color change. Following the colorimetric reaction, images were taken and subsequently analyzed via ImageJ to determine the relative pixel intensity that was used to infer norfloxacin concentration. The analytical sensitivity of this device was determined to be as low as 50 ppm when analyzing the inner-ring reaction, and as low as 5 ppm when analyzing the outer coffee ring thereby allowing for an alternative cheaper, faster, and more user-friendly method to detect norfloxacin than the conventional methods. PRACTICAL APPLICATION: This novel paper-based microfluidic device can achieve the detection of antibiotic residues in agrifoods in a faster, cheaper, and more user-friendly manner.

A novel type of enzyme-antibody conjugation using mesoporous silicon nanospheres (MSN) was developed, which amplified the labeling signal and highly increased the sensitivity of enzyme-linked immunosorbent assay (ELISA) for the determination of pesticide and veterinary drug residues in food. First, conjugates were prepared through layer-by-layer immobilization of an enzyme and an antibody on an MSN scaffold. Then the MSN scaffold was employed for labeling and signal amplification to develop a sensitive colorimetric immunoassay through the catalytic oxidation reaction of 5,50-tetramethylbenzidine (TMB). When this MSN-based ELISA was applied to detect chloramphenicol, avermectin, tetracycline and streptomycin in food samples, it provided linear ranges of 0.025 ng ml-1-25 ng ml-1, 0.05 ng ml-1-10 ng ml-1, 0.025 ng ml-1-10 ng ml-1 and 0.05 ng ml-1-25 ng ml-1, respectively, with low detection limits down to 0.011 ng mL-1, 0.134 ng mL-1, 0.015 ng ml-1 and 0.106 ng ml-1, respectively. For avermectin, it provided a 16.7-fold decrease of the limit of detection in contrast to that of standard ELISA without the loss of method specificity and accuracy. This novel immunoassay was hypersensitive, simple and easy-to-use, which made it high potential in applying for the accurate analysis of harmful substances in food.

The previously adopted marker residue for florfenicol (FF) in China was only florfenicol amine (FFA); however, the marker residue has been changed to FF plus FFA since the end of 2017. The previous official withdrawal period determined based on the only concentration of FFA may no longer be suitable. Therefore, the present study aimed to determine the depletion profiles of FF and FFA and further calculate the withdrawal period in the crucian carp (Carassius auratus) based on the new marker residues. Florfenicol was intramuscularly administered at 10 mg/kg bodyweight daily for five consecutive days to crucian carps reared in freshwater at 10°C. After the last dose, plasma and tissue samples were randomly collected from 10 fish at different time points. The FF and FFA concentrations were simultaneously determined by high-performance liquid chromatography (HPLC) with a fluorescence detector and further subjected to noncompartmental analysis. The elimination half-life (h) of FF in different tissues decreased as follows: liver (39.1) > kidney (36.3) > skin plus muscle (34.6) > plasma (31.7), whereas that of FFA decreased as follows: kidney (41.4) > skin plus muscle (39.4) > liver (39.3) > plasma (35.7). Considering a maximum residue limit of 1 μg/g for the total concentration of FF and FFA in the skin plus muscle, a withdrawal period of 6 days was calculated based on the upper limit of the one-sided 95% confidence interval.

Carbofuran residue in vegetables is a concern to human health. Direct competitive enzyme-linked immunosorbent assay (dcELISA) and dipstick immunoassay were developed in the present study. The dcELISA showed a 50% inhibition concentration (IC50 ) and working range of 1.3 and 0.2 to 7.5 ng/mL, respectively, while the cutoff value of dipstick immunoassay was 20 ng/mL. Applying the two immunoassays, we achieved the goal of rapid screening of carbofuran residue in commercial vegetables with a simple sample processing method. Among 46 leek, 39 potato, and 39 sweet potato samples, carbofuran residue was detected in 22% of the leek samples, and two samples exceeded the maximum residue limit of China (0.02 mg/kg). In addition, carbofuran residue was found at less than 2.5 ng/g in one potato and one sweet potato samples. The residual level of carbofuran measured by immunoassays agreed well with those determined by ultra-performance liquid chromatography tandem mass spectrometry. To ensure food safety and human health, it is greatly necessary and meaningful to monitor carbofuran residue in commercial vegetables. PRACTICAL APPLICATION: Rapid monitoring of carbofuran residue in vegetables is very necessary and important for consumers, regulatory agencies, and food industry.

AFEX treatment of crop residues can greatly increase their nutrient availability for ruminants. This study investigated the concentration of acetamide, an ammoniation byproduct, in AFEX-treated crop residues and in milk and meat from ruminants fed these residues. Acetamide concentrations in four AFEX-treated cereal crop residues were comparable and reproducible (4–7 mg/g dry matter). A transient acetamide peak in milk was detected following introduction of AFEX-treated residues to the diet, but an alternative regimen showed the peak can be effectively mitigated. Milk acetamide concentration following this transition was 6 and 10 ppm for cattle and buffalo, respectively, but also decreased over time for cattle while tending to decrease (p = 0.08) for buffalo. There was no difference in acetamide concentration in the meat of cattle consuming AFEX-treated residues for 160 days compared to controls. Further investigation is necessary to determine the metabolism of acetamide in ruminants and a maximum acceptable daily intake for humans.

2-(dichloromethyl)-5[4-(methylsulfonyl)-phenyl]-4-(fluoromethyl)-oxazoline (DFC-M, 1) is a key oxazoline-containing intermediate in commercial process for the synthesis of Florfenicol (3), a marketed broad spectrum veterinary antibiotic. DFC-M was not stable in solution due to the presence of oxazoline moiety, which provided further hindrance for analytical sample preparation and HPLC analysis. Hence, the mechanistic study on the in-solution degradation of DFC-M was carried out via online and offline UPLC-HR-ESI-MS as well as in-situ NMR, and the degradation pathways were proposed. This mechanistic information, together with the follow-up solution stability study, provided crucial information regarding the solution handling and mobile phase selection for DFC-M analysis during commercial processing.

Background Grape is an important fruit consumed either fresh or processed, therefore, fungicide misuse of grape has become an issue of global food safety and human health. Pyraclostrobin, and cyazofamid have been applied to grape frequently. Results Here a simple QuEChERS (quick, easy, cheap, effective, rugged, and safe) liquid chromatography mass spectrometry technique has been developed and validated for the determination of pyraclostrobin, cyazofamid and its metabolite CCIM in open field grape samples. The recoveries of these three in the range of 0.01 to 5 mg kg-1 (n = 5) ranged from 73.1% to 97.9%. The relative standard deviations (RSDs) were below 12% for all cases. The limits of quantitation of each analyte was 0.005 mg kg-1 , which was lower than maximum residue limits of not only pyraclostrobin but also cyazofamid. Not only dissipation kinetics but also residue determination was obtained in grape for those three pesticides. Furthermore, their half-lives in grapes were 10.7-30.1 days, recommending the pre-harvest intervals for these three of 14 days. The calculated hazard quotient and acute hazard index lower than 100% illustrated the safety of intake of grape for the Chinese population for not only long-term but also short-term dietary risk assessment. Conslusions The less than 30 day half-life illustrated that pyraclostrobin and cyazofamid could degrade relatively easily in the environment. The long-term and short-term dietary risk assessment also illustrated the intake safety of these three. Thus, a 14 day pre-harvest interval was safe and recommended. The results of this study contributed to environmental protection, food safety and human health. © 2019 Society of Chemical Industry.

Background The application of exogenous plant growth regulator, for example forchlorfenuron (CPPU), on kiwifruits has become an important factor that influences kiwifruit economic efficiency and the health development of the kiwifruit industry. Owing to the slight difference in calyx shape between the kiwifruits treated with CPPU (CPPU-treated kiwifruits) and the kiwifruits without CPPU treatment (CPPU-untreated kiwifruits), this study aims to provide a cheap, quick, convenient, and non-destructive method for identifying CPPU-treated kiwifruits based on the images of kiwifruits captured at visible lights. Results The identification method includes three steps. Firstly, the kiwifruit was extracted from the background by using Otsu algorithm, hole filling operation and 'bwareaopen' function. Secondly, the calyx was extracted by using corrosion, image enhancement, hole filling and closing operations. Finally, the length/width ratio of the minimum enclosing rectangle of calyx region was calculated. The kiwifruit was regarded as a CPPU-treated kiwifruit if the length/width ratio of the rectangle was higher than 1.6. Otherwise, the kiwifruit was regarded as a CPPU-untreated one. The method had the total identification accuracy rate of 90.0% when the kiwifruit images were captured either by utilizing a smartphone at normal lighting condition or by using an image acquisition system. Conclusion The programs run on computer and smartphone were developed, and they could realize kiwifruit identification in 0.6 s and 2 s, respectively. The study makes identifying CPPU-treated kiwifruits in online processing be realizable, and offers a convenient method for kiwifruit consumers. © 2019 Society of Chemical Industry.

This Research Communication describes the residue concentration of a dry cow antibiotic in two different milk fractions and describes effects of milk fraction and milk composition on the test performance of a rapid screening and a microbial inhibitor test. Thirteen dry cows were treated with an intramammary dry cow antibiotic containing 150 mg cefquinome. Quarter foremilk and stripping samples were collected on the first 10 d postpartum. All milk samples were analyzed for milk composition by the local Dairy Herd Improvement Association and were tested for antibiotic residues using the rapid screening test Milchtest BL and the microbial inhibitor test Delvotest BR Brilliant Plates. The residue concentration of cefquinome was determined in foremilk and stripping samples from milkings 1, 2, 3, 5, and 7 after calving using high performance liquid chromatography – tandem mass spectrometry. The logarithm of cefquinome concentration (logCef) was higher in foremilk than in stripping samples and higher in milk samples with lower lactose content. Furthermore, logCef decreased with the number of milkings (P < 0.001). The Milchtest BL was more likely to be not evaluated (i.e. no test and control line or no control line appeared) in stripping samples and milk samples with higher protein content. In the Delvotest BR Brilliant Plates milk samples with higher protein content were more likely to have a false positive result (i.e. the screening test result was positive, but the HPLC-MS/MS result was below the detection limit of the screening test). These results indicate that foremilk is the recommended milk fraction to be tested for residues of cefquinome and that a high protein content can be a cause of test failure and false positive results when milk during the first 10 d postpartum is tested for antibiotic residues using screening tests.

In this study, core–shell lincomycin-imprinted polymers were successfully synthesized and their binding properties evaluated. The functional monomers of methacrylamide and acrylamide were used for synthesis of core and shell, respectively. The optimum synthesized core–shell molecularly imprinted polymer (MIP) was applied as a sorbet in solid phase extraction cartridge. Afterwards, the method of core–shell molecularly imprinted solid phase extraction (CSMISPE) was used for pre-concentration and clean-up of lincomycin in the milk matrix prior to analysis via high performance liquid chromatography equipped with UV detector (HPLC-UV). The linear range for analysis of lincomycin in the milk matrix using introduced method was obtained from 0.08 to 2 μg/mL with recovery range of 80%–89%. The limit of detection and limit of quantification were 0.02 μg/mL and 0.08 μg/mL, respectively. Finally, calibrated CSMISPE-HPLC-UV method was used for lincomycin residue checking and quantification in the pasteurized milk samples of Mashhad city market.

An ultra-high-performance liquid chromatography-tandem mass spectrometry method was developed to analyze cephalexin in swine tissues, urine, and feces. Samples were extracted with 1% sulfuric acid, followed by purification using MCX cartridges. Mean recoveries were 95.4%-100.7% with inter-day relative standard deviations of8.6%. The quantitation limit was 5 μg/kg for fat and urine, and 10 μg/kg for muscle, liver, kidney, and feces. Cephalexin residue depletion was determined using 32 healthy pigs, randomly divided into eight (seven treated and one control) groups. Treated groups were intramuscularly administered 10 mg/kg b.w. five times at 24-h intervals and euthanized 6 h and 1, 2, 3, 5, 7, and 10 days after the last injection. Cephalexin was eliminated rapidly in swine muscle, liver, fat, and feces. The highest concentrations among edible organs were detected in the kidney. Moreover, the longest elimination period of cephalexin in swine was determined in urine. These results indicated that kidney and urine were likely target matrices for cephalexin residue detection in swine.

A rapid and eco-friendly method was developed to extract and pre-concentrate sulfonamides (sulfadiazine, sulfamerazine and sulfadimethoxine) from chicken meat before high-performance liquid chromatographic analysis. The method involved rapid microwave-assisted extraction with hydrochloric acid (pH = 5), further solid phase purification using HLB cartridge and 5% ammonium hydroxide, and homogeneous liquid-liquid microextraction using hexanoic acid as switchable hydrophilicity solvent. The overall time required for sample preparation was 10 min and the volume of organic solvent used for extraction was only 200 μL. The method exhibited good linearity (r2 > 0.9941), low limits of detection (2.5–6.0 ng/g) and allowed quantification of target sulfonamides spiked at levels of 50–400 ng/g in chicken meat with spiked recoveries in the range of 94.1%–112.0%.

The bioavailability and pharmacokinetic disposition of tiamulin in broiler chicken were investigated after administration through the crop, drinking water, and feed at 40 mg/kg body weight. Residues of tiamulin in tissues of broiler chicken were also assessed. Plasma and tissue concentrations of tiamulin were analyzed by reverse-phase high-performance liquid chromatography (HPLC) method. Plasma concentration-time data were described by the non-compartmental model for all three routes, and pharmacokinetic parameters were calculated. There were no significant differences (p > 0.05) in pharmacokinetic parameters and mean plasma concentrations of tiamulin between three routes tested (crop, water, and feed), indicating equal efficacy. Tiamulin residues in edible tissues (muscles, skin, and fat) were lower than the advocated maximum residue limit (MRL of 0.1 µg/g and that of liver was 1 µg/g) on the 3rd day. No traces were found on the 5th day after drug administration. This indicated that the withdrawal period (less than 5 days) is very short, which makes it safer. This study shows that tiamulin can be used with equal efficacy through all routes of administration in broiler chicken (crop, water, and feed).

The available information on drug residue stability in chicken egg is scarce. The objective of this study was to evaluate the stability of drug residues in egg under different traditional cooking procedures. Fresh eggs were spiked with different drug concentrations of albendazole (ABZ) and its albendazole sulphoxide (ABZSO) and albendazole sulphone (ABZSO2) metabolites; flubendazole (FLBZ) and its reduced flubendazole (R-FLBZ) and hydrolyzed flubendazole (H-FLBZ) metabolites; amoxicillin (AMX); and enrofloxacin (EFX) and its ciprofloxacin (CFX) metabolite. The egg samples were cooked in different ways, namely, boiling, microwaving, and omelette making. Drug residue concentrations in egg were quantified by HPLC with UV or fluorescence detectors. ABZ and ABZSO concentrations in egg were not affected by boiling and microwaving, while the omelette processing significantly reduced these molecules. Residues of ABZSO2 in egg were stable or increased after all cooking procedures. In contrast, FLBZ and its metabolites FLBZ-H and FLBZ-R residues in egg decreased after all treatments. The residue concentration quantified for EFX and CFX did not show significant changes after any cooking method. AMX residues were unstable, with extremely significant drug reduction after all cooking processes. Conventional methods of egg cooking cannot be considered a tool to eliminate all veterinary drug residues. Fil: Cantón, Lucila. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias. Departamento de Fisiopatología. Laboratorio de Farmacología; Argentina Fil: Alvarez, Luis Ignacio. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias. Departamento de Fisiopatología. Laboratorio de Farmacología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; Argentina Fil: Cantón, Candela. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; Argentina. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias. Departamento de Fisiopatología. Laboratorio de Farmacología; Argentina Fil: Ceballos, Laura. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias. Departamento de Fisiopatología. Laboratorio de Farmacología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; Argentina Fil: Farias, Cristina Elena. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias. Departamento de Fisiopatología. Laboratorio de Farmacología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; Argentina Fil: Lanusse, Carlos Edmundo. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias. Departamento de Fisiopatología. Laboratorio de Farmacología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; Argentina Fil: Moreno Torrejon, Laura. Universidad Nacional del Centro de la Provincia de Buenos Aires. Facultad de Ciencias Veterinarias. Departamento de Fisiopatología. Laboratorio de Farmacología; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Tandil. Centro de Investigación Veterinaria de Tandil. Universidad Nacional del Centro de la Provincia de Buenos Aires. Centro de Investigación Veterinaria de Tandil. Provincia de Buenos Aires. Gobernación. Comision de Investigaciones Científicas. Centro de Investigación Veterinaria de Tandil; Argentina

Widespread use of coccidiostats, in spite of beneficial control of protozoan infections in poultry, implies a risk of residues in edible tissues, and there is increasing interest in the development of strategies for prevention of veterinary drugs residue in food-producing animals. The aim of this study is assigned to clarify the impact of silymarin addendum in the diet on lasalocid concentration in the liver and breast muscles from the broiler. Four groups of chickens received a feed with lasalocid at levels between 75 and 200 mg kg-1. Other four groups received a feed with lasalocid (75-200 mg kg-1) plus silymarin. Significant differences of lasalocid concentrations between the liver and breast muscles were observed. Moreover, the chickens from the groups supplemented with silymarin shown significant decreases of lasalocid concentrations in the analysed tissues. The herbal substance did not counteract the ionophore in the treatment of coccidiosis and did not change biochemical parameters of blood. These findings suggest that silymarin might be used in chicken feeding in order to reduce the risk from lasalocid contamination of the broiler edible tissues.

Boronate affinity materials are usually used for selective enrichment of cis-diol-containing compounds, mainly based on formation of pH-dependent cyclic ester between cis-diol and boronic acid. Recently, B–N coordination, or combined with hydrogen-bonding interaction, was employed as primary interaction for the extraction of nitrogen-containing compounds. However, there are no reports about the combination of hydrophobic (or π-π) interaction and B–N coordination for the extraction. Here, we prepared a novel hydrophobic phenyl-boronic acid polymer (PBAP) through initiator-free ring-opening polymerization. The adsorption experiment indicated that the PBAP could combine hydrophobic (or π-π) interaction and B–N coordination to enhance their adsorption capacity toward hydrophobic and nitrogen-containing compounds, for example sulfamethoxazole (SMX) and trimethoprim (TMP). In addition, the PBAP monolith synthesized in pipette tip was used as solid phase microextraction (SPME) sorbent with combination of ultra high performance liquid chromatography to extract and monitor SMX and TMP from animal-originated foodstuffs. The proposed method exhibited low limit of quantitation as 5.0 and 1.0 ng mL−1 for SMX and TMP, respectively. The recoveries at three spiked levels were between 92.4% to 100.5% for SMX, and 92.7% to 102.6% for TMP, with intra-day and inter-day relative standard deviations no more than 5.3% and 8.6%, respectively. These results well demonstrated that the combination of hydrophobic (or π-π) interaction and B–N coordination played an important role in the extraction of hydrophobic and nitrogen-containing compounds.

1 A reliable and accurate liquid chromatography-tandem mass spectrometry (LC-MS/MS)-based method was developed to quantify total tulathromycin residues in bovine tissues. Specifically, the above method relied on the quantification of CP-60,300, a marker produced by tulathromycin hydrolysis, for which maximum residue limits (MRLs) were established by the European Union and several other countries. Sample preparation and LC-MS/MS conditions were thoroughly optimized to allow for accurate quantification. The optimized procedure involved sample homogenization with 2 mol/L hydrochloric acid and ethyl acetate, heating of the resulting aqueous layer to convert tulathromycin and its metabolites into the marker residue, cleanup by a polymer-based cation-exchange cartridge, and subsequent analysis by LC-MS/MS. The developed method was validated for tulathromycin A and the marker residue in bovine muscle, fat, and liver at two levels, namely at the MRL set in Japan and at 0.01 mg/kg. Excellent analytical performance was observed, with the average recoveries of tulathromycin A and the marker residue ranging from 98 to 107%, and relative standard deviations ranging from 1 to 3%. Matrix effects were negligible, and analyte loss during sample preparation was minimal for all matrices tested, which allowed for accurate determination by external standard calibration using a solvent standard. No interfering peaks were observed close to the retention time of the marker residue for all matrices, which was indicative of high specificity. Overall, the developed method was proven suitable for regulatory purpose analysis of total tulathromycin residues.

A reliable LC-MS/MS analytical method for the determination of residual triclabendazole and its principal metabolites (triclabendazole sulfoxide, triclabendazole sulfone and keto-triclabendazole) in bovine tissues was developed, in which triclabendazole and its metabolites are oxidized to keto-triclabendazole as a marker residue. The method involves sample digestion with hot sodium hydroxide, thus releasing the bound residues of various triclabendazole metabolites in bovine tissues. The target compounds are extracted from the digest mixture with ethyl acetate, defatted by liquid-liquid partitioning using n-hexane and acetonitrile, then oxidized with hydrogen peroxide in a mixture of ethanol and acetic acid. The reaction mixture is cleaned up using a strong cation exchange cartridge (Oasis MCX) and the analytes are quantified using LC-MS/MS. The optimal conditions for the complete oxidation of triclabendazole and its metabolites to keto-triclabendazole are an incubation time of 16 h and a temperature of 90 °C. The developed method was evaluated using three bovine samples: muscle, fat, and liver. Samples were spiked with triclabendazole and its principal metabolites at 0.01 mg/kg and at the Japanese Maximum Residue Limits (MRLs) established for each sample. The validation results show excellent recoveries (81-102%) and precision (10%) for all target compounds. The limit of quantification (S/N ≥ 10) of the developed method is 0.01 mg/kg. These results suggest the developed method is applicable to quantifying residual triclabendazole in bovine tissues in compliance with the MRLs established by the Codex Alimentarius and EU and Japanese regulations, and thus the proposed method will be a useful tool for the regulatory monitoring of residual triclabendazole and its metabolites.

Accurate and precise application of ion-selective electrodes (ISEs) in the quantification of environmental pollutants is a strenuous task. In this work, the electrochemical response of alendronate sodium trihydrate (ALN) was evaluated by the fabrication of two sensitive and delicate membrane electrodes, viz. polyvinyl chloride (PVC) and glassy carbon (GC) electrodes. A linear response was obtained at concentrations from 1 × 10−5 to 1 × 10−2 M for both electrodes. A Nernstian slope of 29 mV/decade over a pH range of 8–11 for the PVC and GC membrane electrodes was obtained. All assay settings were carefully adjusted to obtain the best electrochemical response. The proposed technique was effectively applied for the quantification of ALN in pure form and wastewater samples, acquired from manufacturing industries. The proposed electrodes were effectively used for the determination of ALN in real wastewater samples without any prior treatment. The current findings guarantee the applicability of the fabricated ISEs for the environmental monitoring of ALN.

A sensitive and reliable method was developed to determine methylene blue (MB) and its metabolite residues, including azure A (AZA), azure B (AZB), and azure C (AZC) in aquatic products by HPLC–MS/MS. The samples were extracted by acetonitrile and cleaned up by alumina-neutral (ALN) cartridges. The analytes were separated on a Sunfire C18 column (150 mm × 2.1 mm, 5 µm). The method was validated according to the European criteria of Commission Decision 2002/657/CE. Good linearity between 1–500 µg/L was obtained with correlation coefficients (R2) greater than 0.99. The limit of quantification (LOQ) was 1.0 µg/kg. The average recoveries at three levels of each compound (1, 5, and 10 µg/kg) were demonstrated to be in the range of 71.8–97.5%, with relative standard deviations (RSDs) from 1.05% to 8.63%. This method was suitable for the detection of methylene blue and its metabolite residues in aquatic products.

A novelty single step clean-up method was developed for analysis of tricaine, tetracaine and bupivacaine in fish tissue combined with high performance liquid chromatography coupled with triple quadrupole-linear ion trap tandem mass spectrometry (HPLC-QTRAP-MS/MS). The target analytes were extracted by acetonitrile based on modified QuEChERS (quick, easy, cheap, effective, rugged and safe) method under ultrasound irradiation. A cheap analytical filtration syringe (CAFS) clean-up column for single step purification was proposed firstly. 300 mg of PSA proposed as optimum purification sorbents. 1 mL acetonitrile extract was transferred into CAFS clean-up column and cleaned for analysis by HPLC-QTRAP-MS/MS. Thelimits of detection (LODs) and the limits of quantification (LOQs) were 2.0 μg kg-1 and 5.0 μg kg-1 , respectively. The recoveries were in the range of 88.73% to 108.72%. Inter-day and intra-day relative standard deviations (RSDs) were lower than 15% for all analytes. The developed method has been applied to measure real samples obtained from local market.

This research communication describes the lactating intramammary (IMM) antibiotic formulation most used by Irish dairy farmers at farm level through interviewing 202 dairy farmers. The IMM antibiotic usage data is not easily available to the researcher and farming community. This study determined that three commercial formulations (Synulox ™, Tetra Delta™ and Terrexine) made up 81% of the products used at farm level. The formulation Synulox™ was the most used at 34% first preference and 32% second preference and contains amoxicillin/clavulanic, a standard broad spectrum antibiotic, for which mastitis pathogen resistance remains low. The aminoglycosides were used in four of the IMM formulations analysed, including Tetra Delta™ and Terrexine. Of the 12 antibiotics identified in the IMM formulations studied, three including cefalexin, benzylpenicillin and penethamate are classified as highly important antibiotics (HIA) by the World Health Organisation (WHO) whilst the other 8 (dihydrostreptomycin, streptomycin, neomycin, framycetin, kanamycin, amoxicillin/clavulanic acid, and cefquinome), are considered critically important (CIA) for use in human health. This study has generated knowledge of the preferences of lactating IMM formulations used at farm level.

Tetracycline (TET) is a broad-spectrum antibiotic, which is frequently used in the prevention and treatment of animal diseases, feed additives, and so on. However, its residue and accumulation in animal-derived foods could cause several side effects to the human body. Herein, we fabricated TET aptamer-pendant DNA tetrahedral nanostructure-functionalized magnetic beads (Apt-tet MBs) as a probe to detect TET. In the presence of target TET, DNA primer was released from Apt-tet MBs since the TET aptamer could specifically bind TET. Next, the separated DNA primer could effectively initiate rolling circle amplification (RCA) reaction and generate a long tandem single-stranded sequence. Finally, with SYBR Green I as the fluorescence dye, the fluorescence signal could be detected by detection probes through hybridizing the RCA product. Under optimal conditions, the fluorescent signal increased with the increasing target TET concentration within the 5 orders of magnitude dynamic range from 0.001 to 10 ng mL-1. The detection limit was calculated to be 0.724 pg mL-1 and the method showed high selectivity toward TET among different antibiotics. More impressively, this method was employed for TET determination in fish and honey samples. The as-obtained results were consistent with those of ELISA kits, holding great potential in the field of food analysis.

Ultrasonic-enhanced surface-active bismuth trisulfide based core–shell nanomaterials were developed and used as an efficient modified electrode material to construct a highly sensitive antibiotic sensor. The core–shell Bi2S3@GCN electrode material was directly synthesized by in-situ growth of GCN on Bi2S3 to form core–shell like nanostar (Ti-horn, 30 kHz, and 70 W/cm2). The electrocatalyst of Bi2S3@GCN nanocomposites was efficaciously broadened towards electrochemical applications. As synthesized Bi2S3@GCN promoted the catalytic ability and electrons of GCN to transfer to Bi2S3. The single-crystalline GCN layers were uniformly grown on the surface of the Bi2S3 nanostars. Under the optimal conditions of electrochemical analysis, the CPL sensor exhibited responses directly proportional to concentrations (toxic chemical) over a range of 0.02–374.4 μM, with a nanomolar detection limit of 1.2 nM (signal-to-noise ratio S/N = 3). In addition, the modified sensor has exhibited outstanding selectivity under high concentrations of interfering chemicals and biomolecules. The satisfactory CPL recoveries in milk product illustrated the credible real-time application of the proposed Bi2S3@GCN sensors for real samples, indicating promising potential in food safety department and control. Additionally, the proposed electrochemical antibiotic sensor exhibited outstanding performance of anti-interfering ability, high stability and reproducibility.

In this study, a new floating dispersive solid phase extraction method based on deep eutectic solvents has been developed in a home-made extraction device for the extraction of four tetracycline antibiotics from milk samples. In this approach, the sorbent (activated carbon) was dispersed in whole parts of solution with the aid of air stream and floated on top of the solution with the aid of the surfactant (lauryl betaine) and air bubbles. After collection of the sorbent, the adsorbed analytes were eluted with tetrabutyl ammonium chloride-propionic acid deep eutectic solvent under sonication. In this method, there was no need of organic dispersive and extraction solvents and the used sorbent was collected on top of the solution and collected without centrifugation. The validation parameters showed that low limits of detection (0.1-0.3 μg/kg) and quantification (0.6-1.0 μg/kg), acceptable enrichment factors (52-60), efficient extraction recoveries (80-91%), and satisfactory relative standard deviations (≤9.8%) were obtained. Eventually, the method was successfully applied on different milk samples and tetracycline was determined in them.

BACKGROUND Imazalil is widely used in agriculture, which may pose a threat to food safety. This study aimed to investigate the fate of imazalil and its main metabolite, R14821 (imazalil-M), in field grapes and apples, and in the processing of fruit wine at the enantiomeric level. RESULTS Analysis method was established to determine imazalil and imazalil-M enantiomers in grape, apple, fruit wine and pomace. The method showed acceptable recoveries of 71.6-99.9% and precision with relative standard deviation of 0.3-11.7%. Processing factors (PFs) were 0.15-0.40 (for imazalil enantiomers) and

A robust and confirmative method was established for the determination of six acetylgestagen residues, namely, flurogestone acetate (FGA), megestrol (MA), melengestrol acetate (MGA), chlormadinone acetate (CMA), medroxyprogesterone (MPA), and hydroxyprogesterone acetate (HPA) in animal-derived matrix samples by utilizing enhanced matrix removal lipid (EMR-lipid) clean-up in combination with ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The analytes were extracted with acetonitrile, purified with a EMR-lipid cartridge, and separated with a reversed-phase C18 column. The limit of quantification (S/N ≥ 10) for CMA, FGA, HPA, MA, and MGA in all matrices was 0.5 ng/g, and for MPA, it was 1.0 ng/g; the limit of detection (S/N ≥ 3) for CMA, FGA, HPA, MA, and MGA in all matrices was 0.1 ng/g, and for MPA, it was 0.2 ng/g. The recoveries were between 61.0% and 114.8%, and the relative standard deviations (RSDs) were below 12%. The method was calibrated in a matrix-assisted standard solution in various linear ranges for the analytes and matrices, and the correlation coefficients (R2) exceeded 0.99 for all the matrices.

β-Lactam antibiotics such as penicillins and cephalosporins are extensively used for human infection therapy. Consistent unintended exposure to these antibiotics via food and water is known to promote antibiotic-resistant bacterial pathogenesis with high morbidity and mortality in humans. An optical enzymatic biosensor for rapid and point-of-use detection of these antibiotics in food and water has been developed and tested. Enzymatic hydrolysis of β-lactams, on the electroactive polyaniline nanofibers, altered the polymeric backbone of the nanofibers, from emeraldine base form to emeraldine salt, which was measured as an increase in evanescent wave absorbance at 435 nm. The sensors were calibrated by spiking antibiotic-free milk with ceftazidime (as a model β-lactam analyte) in a linear range of 0.36−3600 nM (R2 = 0.98). The calibration was further validated for packaged milk, local cow milk, and buffalo milk. A similar calibration was devised for chicken meat samples in a linear range of 9−1800 nM (R2 = 0.982) and tap water in a linear range of 0.18−180 nM (R2 = 0.99). Interestingly, it was possible to use the same calibration for the determination of other β-lactam antibiotics (ampicillin, amoxicillin, and cefotaxime), which reflects the usefulness of the sensor for wide-scale deployment. The sensor performance was validated with a wastewater sample, from a wastewater treatment plant (WWTP), qualitatively analyzed by high-resolution liquid chromatography coupled with mass spectroscopy for detection of β-lactams. The sensor scheme developed and tested is of grassroot relevance as a quick solution for measurement of β-lactam residues in food and environment.

The aim of this study was the detection of ethinyl estradiol and resorcylic acid lactones (zeranol and taleranol) in poultry meat samples as unauthorized substances included in the Italian national residue plan. The samples were purified by a solid phase extraction using a C18 column combined with alumina, and the analytes were detected by two specific enzyme-linked immunosorbent assay (ELISA) kits. As they were collected in the frame of official control activities, the method was also validated according to the Commission Decision 2002/657/EC requirements for screening methods with qualitative purpose. Specificity and detection capability were the performance criteria considered for the validation study, and the latter parameter showed a value of 0.5 μg/kg for both the investigated compounds. Such result was well comparable with the data reported by using chromatographic techniques as confirmation methods, and therefore, the ELISA kits tested in this study could be used for the screening of large numbers of samples.

Sows were fed naturally contaminated diets containing: (i) 100 ppb zearalenone (ZEN) one week before farrowing and during the lactation period (at 26 days), (ii) 100 ppb ZEN one week before farrowing and 300 ppb ZEN during the lactation period, or (iii) 300 ppb ZEN one week before farrowing and during the lactation period. All diets contained 250 ppb deoxynivalenol (DON). The highest levels of ZEN, &alpha, ZEL, or &beta, ZEL were observed in the serum of sows fed 300 ppb ZEN before farrowing and during lactation. However, only &alpha, ZEL was significantly increased in the colostrum and milk of these sows. Sows fed the 300 ppb ZEN during the complete trial presented a significant decrease in backfat thickness before farrowing. This effect was accompanied by a decrease in serum leptin levels. These sows also presented a decrease in estradiol levels and this effect was observed in their piglets exposed during lactation, which presented increased glucagon-like peptide 1, but no changes in serum levels of ZEN, &alpha, ZEL. Although all sows were fed the same levels of DON, the serum levels of DON and de-epoxy-DON were increased only in the serum of piglets from the sows fed a diet with the highest ZEN levels during the whole experimental period. Moreover, these piglets presented gut inflammation, as indicated by significantly increased calprotectin levels in their serum.