Molecularly imprinted dispersive solid-phase microextraction sorbents for direct and selective drug capture from the...

The preparation of well-defined new hydrophilic molecularly imprinted polymer (MIP) microspheres and their use as the dispersive solid-phase microextraction (dSPME) sorbents for direct and selective drug (i.e., propranolol) capture from the undiluted bovine serum are described. These MIPs have surface-grafted dense poly(2-hydroxyethyl methacrylate) (PHEMA) brushes with different molecular weights and grafting densities. They were readily prepared via the facile reversible addition-fragmentation chain transfer (RAFT) coupling chemistry. Both the molecular weights and grafting densities of PHEMA brushes showed significant influence on their complex biological sample-compatibility, and only those MIPs bearing PHEMA brushes with high enough molecular weights and grafting densities could selectively recognize propranolol in the undiluted pure milk and bovine serum. In particular, they have proven to be highly versatile dSPME sorbents for directly and selectively capturing propranolol from the undiluted bovine serum with satisfactory recoveries (85.2-97.4%) and high accuracy (RSD = 2.3-3.7%), even in the presence of one analogue of propranolol. The limit of detection was 0.002 μM with a linear correlation coefficient of 0.9994 in the range of 0.01-100 μM. Excellent precision was verified by both the intraday and interday analytical results. Their good reusability was also confirmed. This work demonstrates the high potential of such hydrophilic MIP-based dSPME sorbents for rapid, accurate, and reliable drug determination in complex biological samples.