Development Of Methods For Determination And Confirmation Of Macrolides And Lincomasides Multi-residues In Food Derived From Animals

Macrolides are a large class of drugs used widely,which can be divided into two diverse,macrolide antibiotics and macrocyclic lactones.Macrolide antibiotics are widely used in veterinary medicine to treat respiratory diseases and enteric infections in cattle, sheep,swine and poultry.However,they are also employed as feed additives to promote animal growth.Macrocyclic lactones(MLs) have found widespread application in hunman and animal health and crop protection,and are used to combat parasitic infection,such as roundworms,lungworms and mites.In veterinary treatment,combination of antibiotics from different group is very popular. Combination can result in better effect than one be used separately,as it did in the case of Lincomycin Hydrochloride and Spectinomycin Sulfate Premix(in a ratio 1:2).The combination can prevent and treat chronic respiratory of respiratory disease of growing poultry,mycoplasmal infections or dysentery.Incorrect use of these antibiotics may leave residues in edible tissues causing toxic effect on consumers,e.g.allergic reactions in hypersensitive individuals,or indirectly, problems through the induction of resistant strains of bacteria.Macrocyclic lactones are low-toxins,but the presence of residues may affect consumer health.Many muti-resisues methods about these drugs have been reported,but they can not determinate different class simutanously and analyse only several.Therefore,simple and reliable analytic methods are required to monitor these drug residues in the edible tissues of livestock animals.The first method is to determinate macrolides in edible tissues by HPLC-MS/MS.The samples were extracted with mixture of metheanol and acetonitrile(1:1).Then the extract was defatted with hexane and evaporated to nearly dryness at 40℃.The residue was dissolved in metheanol and evaporated to dryness under a stream of nitrogen.Then the residues was dissolved with mobile-phase and centrifuged in 12000rpm,10μL of which was injected into HPLC-MS/MS.Determination was performed in SRM mode.The experiment indicated that,an averaged decision limits(CCα;α1%) and detection capability(CCβ;β5%) of the method were in the range of 0.3μg/kg～1.5μg/kg and 0.5μg/kg～2.5μg/kg in the tissues,respectively.The average recoveries of different fortified samples of Marolides were in the range of 64.3%～88.0%;the average standard derivations were in the range of 4.6%～24.3%.The second method is based on solide-phase extraction and pre-derivatized,which can determinate Lincomycin and Spectinomycin in several tissues by GC and confirme Lincomycin,Clindamycin and Spectinomycin by GC-MS.The samples were extracted with phosphate buffer and cleaned up with C₁₈ solid-phase extraction(SPE).The cartridge was eluted with 4 ml of methanol and the eluate was evaporated to dryness in a stream of nitrogen at 40℃.Then acetonitrile and BSTFA were added to the tube and the mixture reacted at 75℃for 60 min.The raimnant was evaporated to complete dryness with a stream of nitrogen.The residue was dissolved in hexane,1ul of which was injected into GC or GC-MS.The quantitative methed indicated that,LOD and LOQ of Lincomycin in tissues is 20μg/kg and 30μg/kg,of Spectinomycin is 30μg/kg and 40μg/kg.The average recoveries of four different fortified samples of Lincomycin and Spectinomycin were in the range of 70.6%～86.5%;the average standard derivations was below 12.6%.The confirmation method was based on the SIM mode.The quanitative ions for Lincomycin,Clindamycin and Spectinomycin were 126,126 and 145,respectively.Under this condition,the LOD for Lincomycin,Clindamycin and Spectinomycin were 3μg/kg, 15μg/kg and 15μg/kg,respectively;the LOQ for Lincomycin Clindamycin and Spectinomycin were 5μg/kg,20μg/kg and 20μg/kg.The average recoveries were in the range of 68.3%～85.2%and the average standard derivations were below 15.1%.The conditions of sample preparation and detection by chromatography and mass-spectrometer were optimized in this study.These two methods were to simultaneously determinate the residues of drugs from different class.The methods were new and in the frontiers of residue analysis.The deveiopment of the methods provide technical support for monitoring of residues of these drugs in food derived from Animals.