| An experiment was conducted with JingHai laying hens to establish the HPLC-FD method for determining Thiamphenicol, florfenicol and florfenicol amine residues, at the same time, to study the residues and elimination of thiamphenicol, florfenicol and florfenicol amine in egg white,egg yolk and egg by taking orally Thiamphenicol (20mg·kg-1·b.w·d) and florfenicol (50mg·kg-1·b.w·d) for 5days. The results indicated that:1.The sample pretreatment method and HPLC-FD method for determining thiamphenicol in egg white,egg yolk and egg were established. The recovery of thiamphenicol in egg white ranged from 83.43%～91.23%, the within day RSD were all less than 5.32%, the between day RSD were all less than 10.75% in egg white. The recovery of thiamphenicol in egg yolk ranged from 77.46%～82.55%, the within day were RSD were all less than 6.11%, the between day were RSD were all less than 11.23%. The recovery of thiamphenicol in egg ranged from 86.35%～93.76%, the within day RSD were all less than 6.62%, the between day RSD were all less than 10.83%. Thiamphenicol concentration ranged from 0.025mg·L-1～5.0mg·L-1 had a good linear coefficient relation (r=0.9997,n=8). The minimal detectable limit was 3μg·kg-1. The method can meet the demand of sample determination of Thiamphenicol in egg.2.The sample pretreatment method and HPLC-FD method for determining florfenicol and florfenicol amine in egg white,egg yolk and egg were established. The recovery of florfenicol and florfenicol amine in egg white ranged from 81.36%～97.87% and 83.71%～97.14%, respectively,the within-day RSD were less than 6.34% and 5.62%, the between day RSD were less than 11.35% and 11.51%. The recovery of florfenicol and florfenicol amine in egg yolk ranged from 74.36%～87.45% and 79.61%～97.23%,the within-day RSD were less than 7.37% and 5.82%, the between day RSD were less than 12.52% and 10.36%.The recovery of florfenicol and florfenicol amine in egg ranged from 87.41%～92.29% and 89.01%～95.15%, respectively, The within-day RSD were less than 6.73% and 5.82%, the between day RSD were less than 10.48% and 10.52%. Florfenicol concentration ranged from 0.01mg·L-1～10.0mg·L-1 had a good linear coefficient relation (r=0.9997,n=9).florfenicol amine concentration ranged from 0.0025mg·L-1～2.5mg·L-1 had a good linear coefficient relation(r=0.9998,n=9).The minimal detectable limit of florfenicol was 3μg·kg-1. The minimal detectable limit of florfenicol amine was 1μg·kg-1. The method can meet the demand of sample determination of florfenicol and florfenicol amine in egg.3.Simultaneous determination of thiamphenicol,florfenicol and florfenicol amine in egg white, egg yolk and egg by HPLC-FD method was established.The recovery of Thiamphenicol, florfenicol and florfenicol amine in egg ranged from 83.85%～92.41%,81.21%～97.64% and 81.26%～87.61%, respectively. The recovery of Thiamphenicol, florfenicol and florfenicol amine in egg yolk ranged from 86.65%～93.23%,87.83%～92.27% and 89.56%～95.86%.The recovery of Thiamphenicol, florfenicol and florfenicol amine in egg ranged from 77.56%～91.94%,74.82%～87.38% and 78.87%～97.36%. The minimal detectable limit of Thiamphenicol, florfenicol and florfenicol amine was 3μg·kg-1, 3μg·kg-1 and 1μg·kg-1.4.The residue and elimination of thiamphenicol was studied in egg after taking orally thiamphenicol (20mg·kg-1·b.w·d) for 5days. During medication period, the content of thiamphenicol in egg white , egg yolk and egg was augmented by medication days increase, the maximum content of thiamphenicol was detected at the first day after withdrawal time in egg white , egg yolk and egg, they were 0.15721mg·kg-1,0.18221mg·kg-1 and 0.13732mg·kg-1. and the content of thiamphenicol in egg yolk was more than the content of thiamphenicol in egg white. During withdrawal time, the content of thiamphenicol in egg white, egg yolk and egg was reduced by withdrawal time increase. At the early days, the thiamphenicol residues eliminated very fast, but it was very slow at the later period, at the fifth day after withdrawal time, the content of thiamphenicol in egg white can not be detected(3μg·kg-1). At the seventh day after withdrawal time, the content of thiamphenicol in egg can not be detected(3μg·kg-1). At the eighth day after withdrawal time, the content of thiamphenicol in egg yolk can not be detected (3μg·kg-1). And the residues of thiamphenicol in egg yolk eliminated slower than the residues of thiamphenicol in egg white.5 The residues and elimination of florfenicol and florfenicol amine were studied in egg after taking orally florfenicol (50mg·kg-1·b.w·d) for 5days. During medication period, the content of florfenicol and florfenicol amine in egg white , egg yolk and egg was augmented by medication days increase, the maximum content of florfenicol was detected at the first day after withdrawal time in egg white, egg yolk and egg, they are 0.66201mg·kg-1,0.75733mg·kg-1and 0.70227mg·kg-1, the maximum content of florfenicol amine in egg white and egg were also detected at the first day after withdrawal time, it was 0.36863mg·kg-1, the maximum content of florfenicol amine in egg were detected at the second day after withdrawal time, it was 0.63869mg·kg-1, but the maximum content of florfenicol amine in egg yolk was detected at the third day after withdrawal time, it was 0.95047mg·kg-1. During withdrawal time, the content of florfenicol and florfenicol amine in egg white, egg yolk and egg was reduced by withdrawal time increase. Florfenicol amine in egg white can not be detected at the fifth day after withdrawal time(1μg·kg-1).Florfenicol in egg white can not be detected at the sixth day after withdrawal time(3μg·kg-1). Florfenicol in egg can not be detected at the ninth day after withdrawal time(3μg·kg-1). At the tenth day after withdrawal time, florfenicol amine in egg yolk and egg can not be detected(1μg·kg-1), florfenicol in egg yolk also can not be detected(3μg·kg-1). the residues of florfenicol and florfenicol amine in egg yolk eliminated slower than the residues of florfenicol and florfenicol amine in egg white.6. With the reference of the criterions of the maximum residue limits(MRLs) of European Medicines Agency(EMEA) in chicken meat about thiamphenicol, florfenicol and florfenicol amine, when laying hens took orally thiamphenicol (20mg·kg-1·b.w·d) for 5days, this research suggested the withdrawal time(WDT) should be 4-day; when laying hens took orally florfenicol (50mg·kg-1·b.w·d) for 5days, the WDT should be 7-day. |
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