Ochratoxin Immunoaffinity Column

In this study, a double-recognized aptamer-molecularly imprinted monolithic column (Apt-MIP monolithic column) was prepared by introducing both aptamer and MIP to reduce non-specific adsorption. Its preparation parameters such as the time of photo-initiation, the dosage of photo-initiator and the concentration of aptamer were investigated in detail. The recovery ratios of ochratoxin A (OTA) to ochratoxin B (OTB) on Apt-MIP monolithic column, Apt monolithic column and MIP monolithic column were 116.1, 40.8 and 69, respectively. Even if the concentration of OTB was 10 times that of OTA, the recovery of OTB was only about 2.9%. Applied to beer samples, the prepared Apt-MIP monolithic column drastically resisted background adsorption and the high-specificity recognition for OTA was obtained with the recoveries of 95.5-105.9%. This work provided a simple and effective method to selectively identify OTA from complex samples. (c) 2019 Elsevier B.V. All rights reserved.

a dual DNA tweezers nanomachine was developed for one-step simultaneous detection of aflatoxin B1 (AFB1) and ochratoxin A (OTA) in food samples. The dual DNA tweezers are locked by the aptamers of mycotoxins, resulting the "turn off" of fluorescent signal. In the presence of AFB1 and OTA, the aptamers can bind with their corresponding targets, resulting the "open" of DNA tweezers and the "turn on" of the fluorescent signals. The limits of detections were 3.5 x 10(-2) ppb for AFB1 and 0.1 ppb for OTA. Moreover, the applicability of the method was further demonstrated by conducting a limited survey on 5 samples collected from various sources. The recoveries of this method change from 90.0% to 110.0% for simultaneous detection of AFB1 or OTA and the RSDs vary from 4.1% to 9.2%. Detection uncertainties were within 5% (with a 95% confidence level).