Study On The Ractopamine Colloidal Gold Test Strip

Ractopamine, as a β2-agonist,can improve. the ratio of lean of animals when add to the feed.But it has adverse effect against human bodies when human consume ractopamine which exist inanimal tissues. Currently, the detection of ractopamine is used chromatography, butchromatography needs tedious sample pretreatment method, high cost, specialized testingequipment, which is not suitable for large scale promotion. So, the establishment of an efficientand rapid method to detect ractopamine has important practical significance.In this paper, the trisodium citrate was used as reducing agent to prepare colloidal gold. Thesingle factor test is adopt to prepare colloidal gold, the preparation were screened by changingthe amount of trisodium citrate, henting time, stirring speed and different order of addition ofreactants, the result showed that under the condition of the amount of trisodium citrate was1.8mL, henting time was10min, stirring speed was300r/min can be prepare colloidal gold ofgood quality. UV spectrophotometer was used to evaluate diameter and uniformity of goldparticles. Experiment result showed that the particle size of colloidal gold was18.4nm. Theuniformity of gold particles was also good by observation of the visible spectrum. Thepreparation conditions of immune colloidal gold ware optimized. The optimal labeled antibodyproportion was13.18μg/mL and suitable pH was8.0, the final concentration of1％BSA wasselected as stabilizer. The optimal formula was selected by contract to different solution todissolve colloidal gold precipitation. The formula2was selected to dissolve colloidal goldprecipitation. The coating concentration of antigen was0.5mg/mL and anti-mouse antibody was1.0mg/mL, the dilution of gold-labeled antibody was3times, drying conditions of colloidalcoated with antibody was45min at room temperature and antigen coating was10min at37℃.Observe the effects of different conjugate pad, nitrocellulose filter membrane, sample pad,absorbent paper on performance of colloidal gold test strip, MA0270, Millipore135, GL-b01,HS5072was selected as conjugate pad, Nitrocellulose filter membrane, sample pad, absorbentpaper. The sensitivity of test strips was20ng/mL, having no significant cross-reaction withclenbuterol, salbutamol and epinephrine. Colloidal gold test trips can be stability in2months atroom temperature. There were no difference between same batch and multi-bath. Newpre-treatments was applied to detect ractopamine resident with the method of test strip. Thepositive samples can de detected above20ng/mL range in actual testing process.