Studies On LC-MS/MS Method For The Determination Of Chlortetracycline And4-Epi-Chlortetracycline Residue In Chicken Muscle And Liver And Its Residues And Excretions In Broiler Chickens

An experiment was conducted with AA broiler chickens to establish a method of the Liquid chromatography coupled with tandem quadruple mass spectrometry (LC-MS/MS) to detect Chlortetracycline (CTC) and4-Epi-chlortetracycline (ECTC) in chicken muscle and liver. At the same time, the residues of CTC and ECTC in chicken muscle, liver and excreta were studied. The results indicated that:1. The sample pretreatment method and LC-MS/MS method for the determination of CTC and ECTC in chicken muscle and liver were established.The recovery of CTC and ECTC in chicken muscle were between73.00%and101.60%, the intra-day RSD and inter-day RSD were lower than11.55%and12.92%, respectively; The recovery of CTC and ECTC in chicken liver were between67.06%and106.98%, the intra-day RSD and inter-day RSD were lower than10.84%and10.91%, respectively. The calibration curve was linear in a concentration range of0.005～0.2μg·mL-1for CTC and0.025～0.8μg·mL-1for ECTC, the correlation coefficient was0.9935for CTC and0.9907for ECTC (n=5). The limit of quantitation(LOQ) is10.0μg·kg-1、30.0μg·kg-1for CTC and ECTC, respectively. This method meets the demand of residues determination of CTC and ECTC.2. The residues of CTC and ECTC were detected in chicken muscle and liver after broiler chickens were feed CTC contained40mg/kg and100mg/kg for12days, the results indicated that: The CTC and ECTC residues in chicken muscle and liver after administration of CTC were detected. The concentration of ECTC was23.05%～50.47% of the total residues. Residues of CTC and ECTC in chicken muscle and liver were positively correlated with CTC orally administered doses.The residues of ECTC and CTC in liver were more than muscle.3. The residues of CTC and ECTC in chicken muscle, liver and chicken excreta were studied after the broiler chickens taking orally CTC capsules of50mg·kg-1of body weight once every day for5days. The results indicated that: The CTC and ECTC residues in chicken excreta after administration of CTC were detected. The residue of CTC and ECTC had kept the low level in chicken muscle and liver, most of the residues were brought to environment by chicken excreta.The highest concentration of CTC (contain ECTC) in chicken excreta got up to169781.86μg·kg-1, it’s still2909.64μg·kg-1after withdrawal for6days.