Microextraction Tech

Molecularly imprinted polymers (MIPs) are widely employed sorbents due to their improved selectivity. They are synthesized in the presence of the analyte, which is called template, and therefore the polymeric network is constructed around the target leaving selective chemical cavities when it is washed away. After the bulk synthesis, the polymer is crashed and sieved to obtain a solid with a particle size as homogeneous as possible. In a recent article published in Analytical and Bioanalytical Chemistry, researchers from the Tianjin Medical University at China have proposed a smart MIP monolith for the extraction of ketoprofen from milk samples. In an old post entitled “ Smart molecularly imprinted hydrogels for protein recognition ”, we discussed the advantages of these materials that combine the selectivity enhancement of MIPs with the advantages of smart polymers. In short, a smart polymer is a porous polymeric network that may respond to external stimulus (mainly pH, ionic str...

Solid phase extraction (SPE) is a consolidated technique in sample pretreatment thanks to its robustness, enrichment capacity and selectivity enhancement. The great variety of commercial sorbents covering a wide range of interaction mechanisms, as well as the development of novel materials makes SPE a very versatile technique. Despite its usefulness, classic SPE still presents some shortcomings such as the requirement of moderate to high sample volumes or the use of organic solvents in the milliliter range. These limitations have been faced up by different research groups and as a consequence of these efforts new techniques, for instance microextraction by packed sorbent or pipette tip extraction, have emerged. Pipette tip extraction is based on a simple but innovative idea which consists in placing the sorbent inside a pipette tip. This approach allows the handling of low sample volumes requiring also lower volumes of organic solvents in the elution step. The sorbent can be used...