Development of an aptamer-based sorbent in polypropylene tubes for bisphenol A extraction in water samples

In this work, a novel, efficient and cost-effective aptamer-based sorbent is described for the first time, using a polypropylene (PP) tube as a support for the selective isolation and preconcentration of bisphenol A (BPA). To achieve this, the inner surface of the bottom of a commercial PP tube was vinylized to enable the immobilization of a thiol-modified aptamer against BPA using straightforward "thiol-ene" click chemistry.

The resulting aptamer-modified tube (Apt-MT) was properly characterized and used as sorbent, with key extraction parameters systematically optimized to achieve the best extraction efficiency of BPA. Studies on adsorption behaviour and selectivity of the Apt-based sorbent were also investigated. Under the optimized conditions, the oligosorbent, combined with HPLC with fluorescence detection, provided low detection limit (0.05 μg L^-1) for BPA. The method was successfully applied to several environmental water samples from different sources, yielding recovery values between 83 and 93 % with relative standard deviations below 8.7 %. Moreover, the developed Apt-MT sorbent exhibited excellent reusability, keeping its extraction efficiency for at least 30 cycles.

This study demonstrates the potential of an aptamer-functionalized PP tube as a practical and reusable sorbent for selective BPA isolation and preconcentration in environmental analysis, offering a cost-effective and efficient alternative for contaminant monitoring.