Preparation and evaluation of a tryptophan based hypercrosslinked porous polymer as an efficient adsorbent for pipette tip solid-phase extraction of sulfonamides.

A novel tryptophan-based porous polymer is designed and synthesized via a facile one-step hypercrosslinking polymerization process, and applied as sorbent for extraction of trace sulfonamides in foodstuffs. The developed polymer has high surface area, large conjugate system, and abundant functional groups (e.g., π-π stacking, hydrogen bonding, hydrophobic and electrostatic attraction interactions), which endow it with superior affinity and high adsorption capacity for sulfonamides (16.16-59.29 mg g-1). The optimized SPE method is coupled with HPLC-DAD to create a sensitive and efficient protocol that provides good linearity (R2 ≥ 0.9979), low limits of detection, satisfactory recoveries (92.5-109.5 %) and high precisions (RSDs < 8.24). In addition, the newly proposed method greatly reduces the amount of adsorbent (2.0 mg) and organic solvent (2.0 mL) used. Adsorption kinetics, isotherms, and simulation calculations studies further reveal the presence of monolayer adsorption, chemical adsorption process, and multiple interactions. Thus, this work presents a polymer capable of multiple interactions for the pretreatment of trace sulfonamides in foodstuffs.