Determination of residual enrofloxacin in food samples by a sensitive method of chemiluminescence enzyme immunoassay

A chemiluminescence enzyme immunoassay (CLEIA) based on the HRP-luminol-H2O2 chemiluminescence system for highly sensitive detection of enrofloxacin (ENR) was proposed in this study. Key factors that affect the precision and accuracy for the determination of ENR residues were optimised. Under the optimal conditions, the proposed method showed an excellent performance. The linearity range for method developed for determination of ENR was 0.35-1.0 ng/mL with a correlation coefficient greater than 0.994. The limit of detection was 0.03 ng/mL and the relative standard deviations (RSDs) were less than 9.4% and 13.0% for intra-day and inter-day assays. The proposed method was satisfactorily applied to determine ENR in milk, eggs, and honey samples at three spiked levels (0.4, 0.7, and 1.0 ng/mL) and the recoveries ranged from 92.4% to 104.2% for milk, 93.8% to 103.2% for eggs and 94.1% to 105.0% for honey, respectively. Compared the results of CLEIA with those of ELISA and HPLC, the advantages of the CLEIA were further confirmed. Moreover, one 96-well microtiter plate coated with anti-ENR can be used to detect multiple samples at the same time, which indicated that the CLEIA using HRP-luminol-H2O2 system was a sensitive, high throughput and real-time method for ENR residues analysis.