Siloxane-Free Silicon-Based Copolymer for In-Tube Solid-Phase Microextraction

This study explores the synthesis of a siloxane-free silicon-based copolymer (PEGDMS) by combining ethylene glycol and bis(chloromethyl)dimethylsilane as monomers. The prepared copolymer was designed to mimic the advantageous properties of poly(dimethylsiloxane) (PDMS) and poly(ethylene glycol) (PEG) while addressing their inherent limitations. The PEGDMS copolymer was characterized by using gel permeation chromatography (GPC), nuclear magnetic resonance (NMR), Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). Films based on PEGDMS/TEOS and PEGDMS/Sylgard-184 were then prepared and compared with commercial polymers for several physicochemical properties. These films were further characterized by using FT-IR, TGA, DSC, and X-ray photoelectron spectroscopy (XPS). The PEGDMS copolymer was also employed as a microextraction sorbent for in-tube solid-phase microextraction (IT-SPME) for the preconcentration of a probe mixture of four polycyclic aromatic hydrocarbons (PAHs) before quantification using high-performance liquid chromatography with photodiode array detection (HPLC-PDA). The proposed method demonstrated excellent analytical performance, including low limits of detection (0.95–1.82 ng mL–1), low limits of quantification (3.2–6 ng mL–1), a reasonable linear range (0.1–100 mg L–1), and high coefficients of determination (0.995–0.999). Additionally, the relative standard deviations were consistently below 10% (n = 5).