Study On Residues And Elimination Of Clenbuterol In Swine Tissues And Urine And Determination Of Clenbuterol In Swine Hair By GC/MS

In this paper,we studied residues and elimination of CL in swine tissues and urine,and developed amethod for determination of CL in hair by GC/MS.Twenty-four swines(69.0±2.0kg)were randomly assigned to two groups. And the swines were fed 5or10 mg CL/kg diet respectively for 30 days. Throughout the treatment period urine were collected at 1,2,3,4,6,8,10,14,20,29d respectively. Three swine from each treatment were slaughtered after withdrawalperiods of 0,3,7,14d.After slaughter,urine,serum,liver,kidney and muscle(forelimb,back,crus)were sampled. Samples were prepared by liquid-solid extraction and concentration of CL was determinedby HPLC. The result shows:①CL could be detected in urine at the first day of treatment and quantity ofCL in urine reached peak at 3 or 20 d after treatment in both groups. Moreover quantity was higher in 10mg/kg group than in 5 mg/kg group. ②At zero withdrawal,the concentration of CL in urine was separately338.6ng/ml(5mg/kg)and 1417.0ng/ml(10mg/kg),in liver 243.0ng/g and 352.0ng/g,in kidney 116.8ng/gand 183.8ng/g,in serum 54.0ng/ml and 104.0ng/ml,in muscle 12.4ng/g and 18.7ng/g.③At 7 withdrawal,the concentration of CL in urine was separately 19.7ng/ml(5mg/kg) and 45.1ng/ml(10mg/kg),in liver35.9ng/g and 51.9ng/g,in kidney 12.6ng/g and 19.3ng/g,in serum 8.5ng/ml and 15.5ng/ml,but in musclewas nondetectable(<0.5ng/g).④At 14 withdrawal,the concentration of CL in urine was separately15.1ng/ml(5mg/kg)and 21.8ng/ml(10mg/kg),in liver 16.1ng/g and 41.2ng/g,in kidney 4ng/g and9.6ng/g,in serum 1.2ng/ml and 5.5ng/ml,but in muscle was nondetectable for both groups(<0.5ng/g).The result of this study indicates that residue of CL is higher and elimination of CL is slower in swineurine and liver than other tissues. Therefore they are proper samples for the detection of illegal use ofclenbuterol.A method for determination of CL in swine hair was established initially. CL in hair was extracted by0.1 M HCl. The extract was loaded on a LC-WCX column and CL was eluted from the column byethanol:ammonium hydroxide(98∶2,V∶V) and determined after derivation by GC/MS. Recovery is inthe range of 89.6%~109% in swine hair, RSD is from 4.76% to 6.74%.The LOQ and LOD of the methodare separately 0.05 mg/kg and 0.01 mg/kg. The result shows that the method is accord with demand ofdetection.