Efficient sol-gel immobilization of microporous polymer on silica-based adsorbent for the enrichment of non-steroidal anti-inflammatory drugs

Para-cyano conjugated microporous polymer (PCCMP, surface area of 784 m2 g−1 and pore size of 1.29 nm) was immobilized on the outer surface of the silica microsphere by means of intercalation within sol-gel based outer shell. This simple, efficient, and cost-effective method of immobilization allowed for a stable combination of multi-functional organic polymer with the silica microsphere without any pre-or post-synthesis chemical treatments. The prepared core-shell adsorbent was packed in an SPE cartridge and used for the enrichment of non-steroidal anti-inflammatory drugs (NSAIDs) in water and acetate buffer samples prior to the analysis by HPLC-UV. The prepared adsorbent was characterized by Fourier-transform infrared spectroscopy (FTIR), X-ray photoelectron spectroscopy (XPS), elemental analysis, field emission scanning electron microscope (FESEM), transmission electron microscopes (TEM). The optimization of the sampling-, enrichment-, and elution-conditions were thoroughly investigated. Detailed investigations of the analytical parameters influencing the extraction efficiency were validated. At optimum pre-determined conditions, the prepared adsorbent allowed for good linearity (r2 > 0.9982), run-to-run reproducibility (RSD <7%) with good limits of detection, and limits of quantitation of (0.33–1.46 ng L−1) and (1.1–4.8 ng L−1), respectively. Compared to the commercially recommended SPE adsorbent for NSAIDs, the PCCMP-SPE adsorbent showed enhanced affinity and enrichment capabilities.