ИСТИНА

The monitoring of environmental samples for mycotoxins and pesticides is considered to be a matter of great importance. Direct competitive enzyme-linked immunosorbent assays (ELISAs) for ochratoxin A (OTA) and 2,4-dichlorophenoxyacetic acid (2,4-D) were developed. To increase the sensitivity the novel potent enhanced chemiluminescence reaction (ECR) was used. The ECR was based on luminol oxidation, where anionic soybean peroxidase and 3-(10’-phenothiazinyl)-propane-1-sulfonate were applied as a label and enhancer, respectively. It was shown that the values of the lower detection limit, IC50 and the working range for OTA and 2,4-D were 0.02, 0.08, 0.02-0.30 ng/mL and 1.5, 64, 6.5-545 ng/mL, respectively. Using the chemiluminescent ELISA for determination of OTA the recovery from 3 spiked samples produced by extracting soy beans and containing different OTA concentrations (0.07, 0.1 and 0.15 ng/mL) was estimated. The recovery values were ranged from 72 to 125%. The recovery from 3 spiked samples of Vietnamese oranges containing different 2,4-D concentrations (10, 100 and 300 ng/mL) was 92-104%. Using the chemiluminescent ELISA the concentration of 2,4-D was determined in real samples of the oranges.