Cost effective imprinting for purification purposes

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Selectivity is a main issue in any analytical process. Many strategies can be proposed to achieve the highest value of this basic analytical property. Among them, the use of selective sorbents can be highlighted. There are several alternatives that can be used to synthesize them, being the molecular imprinting one of the most reported. The so-called molecularly imprinted polymers (MIP) are usually employed to selectively isolate and preconcentrate target compounds from the sample matrix. Despite their potential, the synthetic process is complex and it requires the use of the target molecule to create the sterically and electrically recognition site on the polymeric network. It has two main inconveniences: a) the cost of the analyte which is used as template and b) the need for a complete elimination of the analyte to avoid memory effects. These negative aspects are relevant which MIP are intended to be used in a purification technique where the cost of the procedure exponentially increases.
Journal of Separation Science has published a very nice contribution where the authors have minimized these two limitations in the case of purification of an antioxidant compound (punicalagin) extracted from pomegranate husk extract (1). They use (i) the macromolecular crowding biological concept which consists of using a linear polymer (PS) to promote the binding affinity of the polymer towards the template and (ii) the virtual template imprinting where the target analyte is substituted by a structural analogue to create the recognition sites.

The synthetic route is deeply described in the paper as well as the comparison of the performance of the MIPs obtained with and without the addition of the linear polymer. The material can be sued in a SPE format to purify punicalagin from the sample matrix with a recovery of ca. 85% in less than 40 min.

We think that this preparative facet of the microextraction technique is also interesting for our readers and it can also be adapted to other separation fields.

Reference

(1) Cost-effective imprinting combining macromolecular crowding and a dummy template for the fast purification of punicalagin from pomegranate husk extract. Link to the article

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