M. Zhao,K.-Z. Xie,H.-S. Guo,A.-H. Li,X. Xie,G.-X. Zhang,G.-J. Dai,J.-Y. Wang
A residue depletion study of ampicillin (AMP) was performed after oral dosing (60.0 mg/kg and 120.0 mg/kg body weight once a day for 5 days) to laying hens, through the use of reversed-phase high-performance liquid chromatography with fluorescence detection (RP-HPLC-FLD) to achieve detection of ampicillin residue in eggs. Limit of detection was 0.5 ng/g, and limit of quantitation was 1.2 ng/g for ampicillin. Extraction recoveries of ampicillin from samples fortified at 5.0–125.0 ng/g levels ranged from 77.5% to 84.6% in albumen, 77.9% to 87.5% in yolk, and 77.9% to 88.6% in whole egg, with coefficients of variation ≤9.3%. The maximum concentrations of ampicillin in albumen, yolk, and whole egg were detected at 1, 2, and 1 day after the last administration of ampicillin, respectively. Ampicillin was not detectable in albumen at day 9 of withdrawal time, at day 10 and 11 in yolk, and day 9 and 11 in whole egg at each of those 2 dose levels. The theoretical withdrawal time of AMP in whole egg was 6.730 and 7.296 days for 60 and 120 mg/kg oral dosage, respectively. This method also proved to be suitable as a rapid and reliable method for the determination of ampicillin in other poultry eggs.
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.
Can Cui,Xiaojun Jiao,Xianbin Xu,Jiongzhou Gong,Jiaxin Zhou,Ge Tian,Liwei Lu,Li Li,Xianhui Huang
The presence of residues of veterinary drugs in eggs is an ongoing and significant issue of concern. Fluralaner is widely used in the prevention of ectoparasites, including the poultry red mite, but no analytical method has been reported for detection of its residues in eggs. An HPLC-MS/MS method was established for the determination of fluralaner residues in whole eggs and validated for LOD, LOQ, specificity, linearity, accuracy, precision, and matrix effects. LOD was 5 μg•kg −1 and LOQ was 65 μg•kg −1 . Recovery ranged from 97.7% to 103.7% (spiked at 65, 650, 1300, and 2600 μg•kg −1 ), while intra-assay and inter-assay coefficients of variation were consistently below 1.5%. A drug withdrawal trial was conducted with 16 laying hens administered a therapeutic dose of fluralaner in drinking water on days 0 and 7, with eggs being analyzed for 23 days. The highest concentration, 1235 μg•kg −1 , was detected on day 13. This was below the European Union maximum residue limit for fluralaner in edible chicken tissues and eggs (1300 μg•kg −1 ). Residues were detectable up to two weeks after cessation of treatment. This method is suitable for routine compliance monitoring of fluralaner residues in egg matrices and may be adapted for analysis of other edible tissues.
危险品化学品经营许可证（带存储）