Abstract

A hierarchically porous adsorbent was fabricated using polyethylene dioxythiophene (PEDOT) embedded in a polyvinyl alcohol cryogel. This adsorbent was designed for use in the in-syringe solid-phase extraction (IS-SPE) of parabens present in beverage samples. The creation of a hierarchical pore system was achieved through a reaction between a hydrochloric acid solution and calcium carbonate, strategically introduced during the cryogel synthesis within a needle hub. The porous structure of the cryogel allowed for efficient entrapment of adsorption materials, significantly increasing the number of available adsorption sites. Additionally, PEDOT was incorporated to enhance paraben adsorption through hydrophobic and π-π interactions. High-performance liquid chromatography was employed to quantify the extracted parabens. Under optimized conditions, the developed method exhibited detection limits ranging from 0.15 to 0.25 µg L^–1 and quantification limits ranging from 0.50 to 1.0 µg L^–1. The technique was successfully applied to assess parabens in various beverage samples, consistently obtaining extraction recoveries between 88.4% and 98.4%, and relative standard deviations (RSDs) below 6%. We conclude that the in-syringe extraction approach offers a straightforward and efficient method, while the composite adsorbent demonstrates ease of preparation and robust reproducibility, allowing for twelve extraction–desorption cycles.