Facile DNA adsorption enabling ammonium-based hydrophilic affinity monolithic column for high-performance online selective microextraction of ochratoxin A

Herein, a facile protocol of simple DNA adsorption on UV-initiated polymerization supports was proposed for effectively fabricating aptamer-based affinity monolithic column. Hydrophilic cationic monolith with an excellent mechanical stability was achieved within 7 min and then massive aptamers were directly bound by DNA charge-dependent adsorption. Strong cationic quaternary ammonium-based monomer was employed to provide effective and stable positive charge surface for aptamer immobilization in a wide range of pH. An ultra-high aptamer coverage density of 6813 pmol/mu L was achieved to gain a highly specific online recognition performance. Limitations such as low aptamer capacity, tedious modification and time-consuming reactions in the traditional biological or covalent modification strategies were avoided. By using ochratoxin A (OTA) as the given analyte, the selective recognition and high recoveries were successfully achieved, and little cross-reactivity towards OTB analogue was only 0.5% even if the content of OTB got up to 125 folds of OTA. Applied to sample analysis, the satisfactory discriminations of trace OTA were obtained at 93.9 +/- 1.9% - 96.5 +/- 1.7%(n = 3)in beer, wheat and chicken liver samples. It might light a cost-effective access to efficiently preparing high-performance affinity monoliths towards the selective in-tube microextraction of OTA. (C) 2021 Elsevier B.V. All rights reserved.

Automated summary

A facile protocol of DNA adsorption on UV-initiated polymerization supports was proposed for fabricating aptamer-based affinity monolithic column, achieving ultra-high aptamer coverage density and highly specific online recognition performance. This approach avoids limitations of traditional biological or covalent modification strategies.