A Qualitative Detection Of Penicillin With Colloidal Gold Immunochromatographic Technique And Preparation Of Detection Reagent

With the rising of the people’s living requirements, the concern of the abuse of the antibiotics in food is keeping growing. So the detection of antibiotics in food is very important in human healthcare with social and economic effects. Currently, there are some commonly used methods to detect the antibiotics, the sensitivity in most of methods can meet the requirement, but the detection steps and procedures of these methods are difficult and complex and thus these are not suitable for the use of grass-roots units. In order to develop a simple and convenient test method and device with the sensitivity of 4ng/mL which is the national standards, in this study, the rapid and simple test was built with the colloidal gold technique, in which the high specificity penicillinase was used in colloidal gold immunochromatographic test to prepare a qualitative detection of penicillin.The following works were performed in this paper mainly includes the following four aspects:1. As the penicillin is a small molecule drug, the competition assay is used to detect penicillin. The reaults showed that there is no test-line and only control-line for the positive results and there are both test-line and control-line for the negative results in this assay.2. The penicillin was conjugated with bio-macromolecular, such as BSA or BTG etc by chemical coupling method---EDC conjugation and then immobilized on the NC membrane. The concentration and coating volume of penicillin-BSA on the NC membrane was optimized and a suitable concentration and coating volume of penicillin-BSA were determined to 1.5mg/mL and 1.0μL/cm, respectively.3. The penicillinase was labeled to the colloidal gold solution through screening the pH of colloidal gold solution and labeled quantity. The concentration and spraying volume were tested on the treated polyester membrane, and the appropriate value are OD=30 and spraying volume of 2.0μL/cm, reapectively.4. By screening the buffer system and detergents that used for treating the sample pad and polyester, the combination of penicillin to penicillinase was enhanced and the intensity of the test-line was also strengethened, meanwhile the selected system and detergents removed the nonspecific binding and getting the best performance of the test.Based on the methods above, we finally prepared the colloidal gold test reagent for qualitative detection of penicillin in milk with the sensitivity of 4ng/mL.