Study On Of Simultaneous Determination Of β₂-agonist Residues In Swine Urine By Liquid Chromatography/Mass Spectrometry

β₂-adrenergic agonists was developed for the therapeutic treatment of asthma andpreterm labor in humans and has been used in domestic livestock for the same purposes.Because they can promote animal growth, improve the lean meat rate so they were usedas feed additives in animal husbandry. The illicit use of these drugs as growth promotersin animals can pose a risk for food safety and consumer protection. For instance,clenbuterol had led to several cases of intoxication outbreaks in humans in the EuropeanUnion and China. On the basis of such epidemiological evidence, The entire class ofβ₂-adrenergic agonists is also strictly prohibited for use in feeds and drinking water inChina. Therefore, it is very imperative to develop a simple and accurate method for thedetection of these drugs in animal feed, so producer compliance with the regulationscould be effectively monitored.In this paper, a high performance liquid chromatography/mass spectrometry（LC-MS） method was developed for simultaneous determination of ClenbuterolHydrochloride, Clorprenaline, Mabuterol In swine urine. And the method is applied todetermine incurred swine urine samples. Urines adjusted pH to9.8with NaOH solutionwere extracted with tert-butyl alcohol and tert-butyl alcohol-methyl ether mixturesolution（50：50, v/v）. The extracts were evaporated, the residues were soluted with0.1%formic acid solution, and cleaned up by cation solid phase extraction columns.The columns were eluted with ammonia methanol. After evaporated, the residue wassoluted with, the analytes were determined. At the fortified levels of0.5,1,5,10,20and50ng/ml, the mean recoveries of β₂-adrenergic agonists ranged from86.4%¹13.0%,the coefficents of variation （CV） ranged from7.6%¹4.6%，the limits of detection（LOD） were0.1ng/ml in swine urine, the quantitations of detection（LOQ） were0.5μg/Lin swine urine.In this study, the average recovery rates were more than86.4%, the CVs werelower than14.6%. We present a sample pretreatment method based on cation solidphase extraction columns to purify urines samples of swine, the sample eluates were determined by LC/MS. The results showed the developed LC-MS was simple, practical,and reliable method for swine urine samples.