Two “turn-on” pattern fluorescence-quenching lateral flow immunochromatographic assays (FLFIAs) based on carbon dot (CD)/silver nanoparticle (AgNP) and quantum dot (QD)/gold nanoparticle (AuNP) fluorescence quenching systems were developed for the specific and rapid detection of enrofloxacin (ENR) in animal-derived food. The visual cut-off values were 0.1 μg L−1 ENR for CD/AgNP-based FLFIA (C-FLFIA) and 0.25 μg L−1 ENR for QD/AuNP-based FLFIA (Q-FLFIA). Meanwhile, the cut-off values were 5 μg L−1 ENR for a traditional AgNP-based lateral flow immunochromatographic assay (Ag-LFIA) and 10 μg L−1 ENR for AuNP-based LFIA (Au-LFIA). In spiked and procured animal-derived food samples (crucian, perch, pork, beef, chicken, and milk), the cut-off values were 0.5–1 μg kg −1 (μg L−1) ENR for C-FLFIA and 1.25–2.5 μg kg−1 (μg L−1) for Q-FLFIA. The cut-off values of the two assays are much lower than the maximum limits of ENR set by standardization agencies around the world.

Two fluorescence quenching immunochromatographic assays based on carbon dots and quantum dots as donor probes for the determination of enrofloxacin

Veterinary drugs are widely used in animal husbandry to prevent and treat animal diseases, to promote animal growth, and to improve the conversion rate of feed. However, the use of veterinary drugs...

Determination of veterinary drug residues in food of animal origin: Sample preparation methods and analytical techniques

A new, more palatable formulation of 10% enrofloxacin enteric-coated granules was investigated to evaluate the pharmacokinetic effect in plasma, the residue elimination in tissues and the clinical efficacy against Actinobacillus pleuropneumonia (APP) and Mycoplasam suis (MS) in pigs. In this study, the enrofloxacin concentrations in plasma and tissues were detected using high-performance liquid chromatography with phosphate buffer (pH = 3) and acetonitrile. The pharmacokinetics and elimination of enrofloxacin enteric-coated granules were performed after oral administration at a single dose of 10 mg/kg body weight (bw) and 5 mg/kg twice per day for 5 consecutive days, respectively. The in vivo antibacterial efficacy and clinical effectiveness of enrofloxacin enteric-coated granules against APP and MS were assayed at 2.5, 5, 10 mg/kg, compared with tiamulin (8 mg/kg) based on establishment of APP and MS infection models. 56 APP strains were selected and tested for in vitro antibacterial activity of enrofloxacin enteric-coated granules. The main parameters of elimination half-life (t1/2β), Tmax, and area under the curve (AUC) were 14.99 ± 4.19, 3.99 ± 0.10, and 38.93 ± 1.52 μg h/ml, respectively, revealing that the enrofloxacin concentration remained high and with a sustainable distribution in plasma. Moreover, the analysis on the evaluation of enrofloxacin and ciprofloxacin in muscle, fat, liver and kidney showed that the recovery were more than 84% recovery in accordance with the veterinary drug residue guidelines of United States pharmacopeia, and the withdrawal periods were 4.28, 3.81, 4.84, and 3.51 days, respectively, suggesting that the withdrawal period was 5 d after oral administration of 5 mg/kg twice per day. The optimal dosage of enrofloxacin enteric-coated granules against APP and MS was 5 mg/kg, with over 90% efficacy, which was significantly different (p < 0.05) to the 2.5 mg/kg group, but not to the 10 mg/kg group or the positive control group (tiamulin). In conclusion, 10% enrofloxacin enteric-coated granules had significant potential for treating APP and MS, and it provided an alternative enrofloxacin palatability formulation.

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Clinical Efficacy and Residue Depletion of 10% Enrofloxacin Enteric-Coated Granules in Pigs.

Development of a new dual electrochemical immunosensor for a rapid and sensitive detection of enrofloxacin in meat samples.

Immunochromatographic assays for ultrasensitive and high specific determination of enrofloxacin in milk, eggs, honey, and chicken

This study investigated the efficiency of an enrofloxacin ELISA test kit to detect the presence of enrofloxacin residues in broiler tissues compared with LC-MS/MS. Broiler tissues from 72 samples consisting of 60 breast muscle, six pools of livers (500 g each) and six pools of kidneys (500 g each) were obtained from six different slaughterhouses. Breast muscle from 10 carcasses and pools of livers and kidneys from approximately 200 carcasses of the same flock were collected from each slaughterhouse. ELISA and HPLC were used to identify and quantify the contamination of the samples with enrofloxacin. A total of 72% of the analysed samples contained enrofloxacin residues detected by the ELISA and 22.2% were detected by LC-MS/MS. The mean values of enrofloxacin contamination found in chicken breast by ELISA and HPLC were 8.63 and 12.25 μg kg(-1), respectively. None of the samples exceeded the maximum limit of 100 μg kg(-1) by both methods set by the European Union as well as the Brazilian Agriculture Ministry. All positive samples for enrofloxacin residues detected by LC-MS/MS were also positive by ELISA. These data confirm the efficiency of the ELISA test, and suggest its use as a screening method for enrofloxacin residues in poultry tissues due to its quick results, low price and ease of applicability.

Andréa M G de Oliveira

Papers

Investigation of enrofloxacin residues in broiler tissues using ELISA and LC-MS/MS