Objective: To establish an indirect competitive enzyme-linked immunosorbent assay (ELISA) for the determination of Cochinchinenin A (CA). Method: Cochinchinenin A-4'-Carboxymethyl ether (CA-4'-CME) was synthesized as hapten. The hapten was attached to Bovine serum albumin(BSA) and ovalbumin(OVA) as artificial antigen by carbodimide method. Anti-CA polyclonal antibody was obtained from mice which were immunized with CA-BSA. A method of the indirect competitive ELISA for CA was established

and the analytical performance of this method was evaluated. Result: The conjugation molar ratio of CA to BSA and OVA were 18:1 and 24:1

respectively

calculated by UV spectrophotometry. The highest titer of Anti-CA sera was 12 000.Standard curve of CA was fitted by four-parameter logistic equation. In the analysis range of 0-0.80 mg·L-1

the correlation coefficient was larger than 0.99.The IC50 and LOD of the method were 0.66 mg·L-1 and 0.045 mg·L-1

respectively. The intra and inter assay precisions were less than 12.5% and 14.7% respectively. And recoveries ranged from 92.7%-118.7% in typical matrixes. The cross-reactivities of five structural analogues of CA were less than 5.38%. Detected by this method

the mass proportion of CA in Chinese Dragon's blood and total flavonoids of Chinese Dragon's blood were 1.27%

3.08% respectively. Conclusion: Indirect competitive ELISA for the determination of CA

with its high sensitivity

specificity and accuracy

can be conveniently used in drug testing and analysis.