Determination of Veterinary Drug Residues in Animal-derived Foods by Liquid Chromatography-Mass Spectrometry

[Objectives]This study was conducted to establish a rapid and effective method for simultaneous extraction of 54 kinds of veterinary drug residues in animal-derived food, including sulfonamides, quinolones, tetracyclines, malachite greens, penicillins, nitroimidazoles, tranquilizers and macrolides, by HPLC-MS. [Methods] The samples were extracted with 80% acetonitrile water(containing 0.1% formic acid), combined with QuEChERS extraction technology and C18 and PSA purification, analyzed by high performance liquid chromatography-mass spectrometry, and quantified by external standard method. The target substances were analyzed on ZORBAX Eclipse C18 chromatographic column using 0.2% formic acid water and 0.2% methanol as mobile phases. The gradient elution mode was used for chromatographic separation and multiple reaction detection. [Results] In the linear range of 0.5-50.0 ng/ml, the linear relationship of the 54 kinds of veterinary drug residues was good, with correlation coefficients(r~2) greater than 0.995, and the detection limits ranged from 0.30 to 1.00 μg/kg. The results showed that the recovery ranged from 75.4% to 118.2% when different matrixes were added for recovery. [Conclusions] This method is simple, efficient, accurate, stable, and highly operable. It is applicable to simultaneous batch screening of veterinary drug residues in animal-derived food, and has high practical application value.

Selection of Test Samples for Monitoring Veterinary Drug Residue in Bred Animals

[Objective] This study aimed to compare the residue situation of cimaterol,a kind of forbidden veterinary drug in hair, urine and flesh of pig, so as to provide theoretical basis for monitoring veterinary drug residue in bred animals. [Method]Total three different concentrations of cimaterol were administered to pigs, and the residue amounts of cimaterol in pig hair, urine and flesh were monitored at different raising stage. [Result] During the administration period, the residue amount of cimaterol was highest in urine, so urine is the suitable sample for rapid detection of cimaterol in manufacturing enterprises. Cimaterol could be accumulated in pig hair,where cimaterol was metabolized slowly. Thus, pig hair can be used as the test sample for tracing illegal use of veterinary drugs and for vivo detection. Flesh can be used as test sample for direct judgment whether cimaterol residue exceeds the relevant standard. [Conclusion] This study will provide certain theoretical basis for drug monitor in animal husbandry.

Application of Liquid Chromatography-Tandem Mass Spectrometry in Determination of Veterinary Drug Residues

With the long -term and irrational use of veterinary drugs and drug additives in the process of animal feeding, the veterinary drug resi- dues in animals and their additives can be ingested into the human body and pose potential threat to human health. Detection of veterinary drug resi- dues are extremely important practical significance to protect the ecological environment and human health. In recent years, liquid chromatography -tandem mass spectrometry has been widely used in vetednary drug residue detection because of its applicability, qualitative and quantitative fea- tures as well as high sensitivity. This article summarized the application of liquid chromatography -tandem mass spectrometry in detection veterinary drug residues from feed, animal products, arid udne as well as illicit drugs and harmful additives.

Analysis of spironolactone residues in industrial wastewater and in drug formulations by cathodic stripping voltammetry

The redox behavior of spironolactone（SP） drug in Britton-Robinson（BR） buffer of pH 2-11 was investigated by differential pulse cathodic stripping voltammetry（DPCSV） and cyclic voltammetry（CV） at hanging mercury dropping electrode（HMDE）.At pH 9-10.5,the DPCSV of SP drug showed two cathodic peaks at1.15 and1.38 V at the HMDE vs.Ag/AgCl reference electrode.In the CV,at pH 9-10,the dependence of the cathodic peak current,Ip,c and peak potential,Ep,c of the second peak（Ep,c2） on the scan rate（n） and on the depolizer（SP） concentrations was typical of an electrode coupled（EC） chemical reaction type mechanism.The plot of Ip,cat 1.380 V of the DPCSV vs.SP concentration at pH 9 was linear over the concentration range of 1.2×1010-9.6×107 M.The lower limit of detection（LLOD） and limit of quantification（LOQ） of the drug were 1.1×1011 and 4.14×1011 M,respectively.The method was successfully applied for the analysis of SP residues in industrial wastewater,in pure form（98.273.1%） and in drug formulations e.g.Aldactones tablet（98.3572.9%）.The method was validated by comparison with HPLC and the official data methods.

Determination of Sulphonamide Antibiotics and Trimethoprim in Wastewater and Sludge Using Liquid Chromatography with Diode-Array Detection

This paper investigates the occurrence of sulphonamide and diaminopyrimidine antibiotics in wastewater and sludge from wastewater treatment plants. In our experiment, they were isolated from wastewater using the solid phase extraction method. In the case of sludge, pressurized solvent extraction techniques were used followed by solid phase extraction. The solid phase extraction method was used for purification and concentration. Sulphonamide and diaminopyrimidine antibiotics were determined using high performance liquid chromatography with diode-array detection. The selected antibiotics were determined in real sludge samples collected from the wastewater treatment plant in Brno-Mod^ice and in real wastewater samples collected from the wastewater treatment plant located on the grounds of the University of Veterinary and Pharmaceutical Sciences in Brno, using the developed and optimized method. Analyses showed that real samples of wastewater contained sulphathiazole 11.82μg/L at the inflow （7.1 μg/L at the outflow）, sulphapyridine 18.57 I.tg/L （12.2 μg/L）, sulphamethazine 13.52 μg/L （8.44 μg/L）, sulphamethoxazole 14.06 lag/L （9.34 Ixg/L） and trimethoprim 521.4 lag/L （422.29 μg/L）. Here it is demonstrated that drugs are removed through the wastewater treatment procedure only partially.

Application of Liquid Chromatography-High Resolution Time-of-flight Mass Spectrometry in the Detection of Raw Milk and Dairy Products

Milk and dairy products are more and more popular with consumers due to their various nutrients, and their quality and safety issues have always been concerned. Therefore, the development of rapid, accurate and simple screening techniques is of great significance. Liquid chromatography-high resolution time-of-flight mass spectrometry has high-resolution and high-throughput detection functions, and has gradually begun to be applied in the detection of milk and dairy products. This paper summarized the application of milk and dairy products in liquid chromatography-high resolution time-of-flight mass spectrometry, laying a foundation for the development of new methods.

CoFe_(2)O_(4) decorated graphene/C_(18)-functionalized mesoporous silica nanocomposites prepared for magnetic enrichment and electrochemical detection of promethazine in beef

Promethazine(PHZ)is used as a sedative in veterinary medicine,and its residue can threaten the health of human.The electrochemical detection of PHZ is suitable method for application in the field.However,the traditional electroanalysis is difficult to perform directly in meat samples due to matrix interference.This work integrates magnetic solid-phase extraction and differential pulse voltammetry for highly sensitive and selective determination of PHZ in beef and beef liver for the first time.CoFe_(2)O_(4)/graphene coated with C_(18)-functionalized mesoporous silica(MG@mSiO_(2)-C_(18))is synthesized as dispersed magnetic adsorbent to extract PHZ.Magnetic glassy carbon electrode modified with nitrogen-doped hollow carbon microspheres(HCM)attracts the MG@mSiO_(2)-C_(18)with PHZ,and directly detects the PHZ without elution procedure.MG@mSiO_(2)-C_(18)can separate PHZ to avoid the interference of impurities on following detection,and also concentrate PHZ on magnetic electrode.Additionally,the electrode modification with HCM can amplify the electrochemical signal of PHZ.Finally,the integrated PHZ determination method exhibits a wide linear range from 0.08μmol/L to 300μmol/L with a low limit of detection of 9.8 nmol/L.The beef sample analysis presents excellent recovery,demonstrating that this protocol is promising for the rapid and onsite detection of PHZ in real meat samples。

Detection and recognition of veterinary drug residues in beef using hyperspectral discrete wavelet transform and deep learning

A fast,non-destructive recognition method for veterinary drug residues in beef was proposed to mitigate the laborious sample preparation and long detection times associated with conventional chemical detection techniques.Control beef samples free of veterinary drug residues and four groups of beef sprayed with relevant concentrations of metronidazole,ofloxacin,salbutamol,and dexamethasone under ambient conditions were analyzed by 400-1000 nm hyperspectral imaging followed by multiplicative scatter correction preprocessing.Data dimension reduction was performed using Competitive Adaptive Reweighted Sampling(CARS),Principal Component Analysis(PCA),and Discrete Wavelet Transform(DWT)based on Haar,db3,bior1.5,sym5,and rbio1.3 wavelet basis functions.Treated data were subjected to Convolutional Neural Network(CNN),Multilayer Perceptron(MLP),Random Forest(RF),and Support Vector Machine(SVM)modelling.CNN,MLP,SVM,and RF algorithms achieved overall accuracies of 91.6%,88.6%,87.6%,and 86.2%,respectively,when combined with DWT(wavelet basis functions and numbers of transform layers being Haar-4,db3-2,bior1.5-4,and sym5-3,respectively).The algorithm Kappa coefficients(0.89,0.86,0.85,and 0.83,respectively)and time consumption for prediction(140.60 ms,57.85 ms,70.67 ms,and 87.16 ms,respectively)were also superior to models based on CARS and PCA.DWT combined with deep learning can shorten prediction times,considerably improve the accuracy of classification and recognition,and alleviate the Hughes phenomenon,thus providing a new method for the fast,non-destructive detection and recognition of veterinary drug residues in beef.

Development of an electrochemical immunoassay for detection of gatifloxacin in swine urine

To detect gatifloxacin （GAT） residue in swine urine, an electrochemical immunoassay was established, An indirect competitive immunoassay was developed, in which the coating antigen is immobilized in an enzyme-linked immunosorbent assay （ELISA） plate and GAT residue from the sample competes with the limited binding sites in added anti-GAT antibody. Horseradish peroxidase （HRP） conjugated to goat anti-rabbit IgG was used as the enzymatic label. A carbon fiber working electrode was constructed and current signals were detected by using hydrogen peroxide as a substrate and hydroquinone as an electrochemical mediator. The electrochemical immunoassay was evaluated by analysis of GAT in buffer or swine urine and an average value of half inhibition concentration （IC50） of 8.9 ng/ml was obtained. Excellent specificity of the antibody was achieved with little cross-reaction with Iomefloxacin （3.0%）, ciprofloxacin （3.0%）, and ofloxacin （1.9%） among commonly used （fluoro）quinolones. In conclusion, the im- munoassay system developed in this research can be used as a rapid, powerful and on-site analytical tool to detect GAT residue in foods and food products.

Free-Standing Membrane Liquid-State Platform for SERS-Based Determination of Norfloxacin in Environmental Samples

Surface-enhanced Raman scattering(SERS)has been widely used in various fields due to high sensitivity,but it is hindered by its low repeatability.Here,we explored a highly reproducible free-standing liquid-state platform(FSM)for monitoring norfloxacin(NOR)in the environmental field.After optimizing the types of nanoparticles(NPs)and pH value in NOR solution,the relative standard deviation(RSD)of FSM SERS analysis can be stabilized below 10%(n≥8),and the R^(2)of the calibration curve in the range of 20μg/L-100μg/L was 0.995.In addition,the results showed that the limit of detection(LOD)(3σ/k)of NOR was 1.3μg/L.Moreover,the NOR in the spiked samples was successfully quantified by FSM,and the recovery rate exceeded 95%.The proposed method has the potential for rapid analysis of drug residues in environmental samples.