Abstract:

A direct competitive chemiluminescene enzyme immunoassay (dc-CLEIA) was developed to detect furantoin
metabolite in animal tissues. The optimal dilutions of monoclonal antibody and enzyme labeled antigen were determined by
chequerboard titration. The effects of coating conditions, blocking solution and competitive reaction time were investigated
by single-factor experiments. The optimized reaction conditions were determined as follows: 4 000-fold dilution of
monoclonal antibody 80-fold dilution of enzyme labeled antigen, 2 h incubation at 37 ℃ for coating followed by overnight
storage at 4 ℃, blocking with 1% BSA, and 1 h competitive reaction. The linear detection range of the developed CLEIA
was 0.030–10.595 ng/mL, and the 50% inhibitory concentration (IC50) value was 0.559 ng/mL. The recoveries in negative
samples ranged from 84.9% to 103.4%. The intra-assay and inter-assay coefficients of variation were 3.4%–7.8% and 4.7%–
11.8%, respectively. The cross-reactivity values were lower than 0.1% with other structural analogues and derivatives expect
for furantoin original drug (36.2%). The CLEIA method was sensitive and accurate, and thus suitable for the fast screening
of furantoin metabolite in food samples.

Key words: furantoin, 1-amino-hydantoin (AHD), direct competitive chemiluminescent enzyme immunoassay, animal tissues