Porous Silsesquioxane-Polyoxazoline Hybrid Materials for Adsorption and Quantification of Pesticides in Environmental Samples

Hybrid adsorbents uniquely combine inorganic thermal stability with organic versatility. This study introduces a class of hybrid materials synthesized by cross-linking octa(vinyl)silsesquioxane (OV-SQ) with poly(2-phenyl-2-oxazoline) (PPhOx) using an AlCl3-mediated Friedel–Crafts reaction, demonstrating the application of this synthetic pathway to PPhOx. A key feature of this synthesis involves adjusting the stoichiometry to retain vinyl groups, facilitating postsynthetic modification via simple thiol–ene click chemistry. Consequently, nonfunctionalized adsorbents were successfully prepared alongside variants bearing alcohol, vicinal diol, and carboxyl functionalities. These resulting hybrids exhibited high surface areas and proved highly effective for adsorbing pesticides from aqueous environments. Detailed adsorption studies revealed that specific surface functionalities drastically influenced capacity; notably, the carboxyl-modified adsorbent displayed exceptional efficiency for removing 2-methyl-4-chlorophenoxyacetic acid (MCPA). Furthermore, these materials were integrated with ambient mass spectrometry (MS) to enable direct pesticide quantification. This combined analytical procedure significantly enhanced sensitivity, improving MCPA detection limits by a factor of 200 compared to standard solutions. This work establishes a versatile synthesis route using PPhOx and highlights the materials’ customizability. Ultimately, the integration of these hybrid adsorbents with ambient MS provides a rapid, efficient framework for screening environmental samples, offering a promising dual-function solution for detecting and removing hazardous contaminants.