Studies On Rapid Immunoassay Of Enrofloxacin

Enrofloxacin is a broad-spectrum antibiotic for the treatment ofanimal tissue infections. With the widespread use in recent years, the sideeffect of enrofloxacin appears increasingly. The enrofloxacin residue inanimal food has been attracted widespread attention at home and abroad. It isnecessary to develop the rapid, effective and economical detection methods ofenrofloxacin. In this study, the two rapid immunoassay methods of directcompetitive enzyme-linked immunosorbent （ELISA） and chemiluminescenceimmunoassay （CLIA） were developed to detect the enrofloxacin residue inanimal food. The results are as followings.1. The content of enrofloxacin, added to animal foods artificially, wasdetected by a direct competitive ELISA and was compared with HPLC. Theindex of the kits was verified. With an concentration range from0.1to8.1ng/mL, the regression equation was y=-0.3769x+0.7899（R²=0.9924）. The50%inhibition percentage (IC₅₀) and sensitivity (IC₁₀) was0.55ng/mL and0.11ng/mL, respectively. The detection limits were3.24g/kg,3.33g/kg,6.08g/kg,0.89g/kg,1.34g/kg,0.64g/L,0.73g/L,0.58g/kg inspiked pork, pork liver, chicken, fish, shrimp, pork serum, milk and honeysamples. The mean intra-assay variability and inter-assay was3.73%and7.42%. The recovery was between80.9%¹00%when spiked to samples at25.0²00g/kg. The correlation coefficients were above95%between ELISAand HPLC.2. The content of enrofloxacin, added to animal foods artificially, wasdetected by a chemiluminescence immunoassay and was compared with thedirect competitive ELISA. The index of the kits was verified. With anconcentration range from1to810pg/mL, the regression equation wasy=-13.898x+110.38（R²=0.9893）. The50%inhibition percentage (IC₅₀) andsensitivity (IC₁₀) was69.63pg/mL and1.41pg/mL, respectively. The meanintra-assay variability and inter-assay was2.61%and4.71%. The detection limits were3.76pg/g,4.59pg/g,2.85pg/g and2.65pg/mL,4.20pg/mL inmilk, honey, chicken, fish, shrimp samples. The recovery was between88.3%¹03%when spiked to samples at50.0¹000pg/g.In this study, based on polyclonal antibodies, a direct competitive ELISAkit and a chemiluminescence immunoassay are developed successfully.Chemiluminescence immunoassay method reduces the detection limit greatly,which lays the foundation for future detection of athlete doping test and limitlower of food harmful substances.