Advancements in mass spectrometry (MS) as detection technologies for the chromatographic separations of samples in complicated matrices have revealed the need for smarter and more efficient sample preparation. Solid phase extraction (SPE), and its miniaturized formats are routinely employed to purify and enrich samples in complex matrices prior to MS analysis. For conventional µ-SPE the adsorbent phase is limited to large 20-80 µm particulate, which allows fast fluid flow without the generation of high backpressures. However, the poor diffusion properties of large particles have negative implications on the recovery and carryover of the analytes. Hence, there is a current drive to develop new adsorbent phases as well as more sophisticated miniaturized devices that allow improved extraction efficiencies over a wide concentration range and facilitate high throughput analysis.

Porous polymer monoliths present an attractive alternative to large particulate adsorbent phases. The high permeability permits fast operational fluid flows at low backpressures while the open porous architecture presents improved mass transfer kinetics optimal for digital µ-SPE. In addition, ease of fabrication permits the development of µ-SPE devices that are capable of directly interfacing with MS for rapid at-line analysis. While polymer monoliths present many attractive advantages for µ-SPE adsorbents their limited surface area can hinder adsorption capacity often crucial for SPE.

In this work high surface area polymer monoliths have been investigated and characterized for µ-SPE. The µ-SPE device with monolithic adsorbent materials were interfaced directly with the ESI-MS for a rapid clean up and analysis of complex biological matrices.