Efficient extraction of quaternary ammonium alkaloids based on π-conjugated polymer coated porous silica adsorbent

The analysis of body fluids (blood, urine, serum, etc.) to accurately detect drug contents has garnered considerable attention in pharmacokinetic and other related studies. Due to the complicated composition of body fluids and low concentration of drugs, efficient implementation of solid phase extraction (SPE) technology is a powerful strategy. This study introduces the preparation of novel π-conjugated polymer modified porous silica (SiO2@π-CP) as adsorbent for extraction of quaternary ammonium alkaloids (QAAs). The preparation process of SiO2@π-CP is easy and the cost is low. Due to the existing of large conjugate structure and rich polar groups (hydroxyl and amine) in π-CP, SiO2@π-CP can form efficient interactions with QAAs (jatrorrhizine, berberine, chelerythrine and sanguinarine as the model analytes). In order to get a better understanding about the adsorption mechanism and process, adsorption kinetics, adsorption isotherms, and thermodynamic studies were conducted. SiO2@π-CP was also proven to have outstanding corrosion resistance and reusability. By investigating the main SPE parameters, the SPE method based on SiO2@π-CP was developed. Excellent results were obtained, including satisfied limits of detections (0.5–2.0 ng/mL), limits of quantifications (0.5–20.0 ng/mL), linearities (0.5–4000 ng/mL), RSDs of inter-day (0.9%–3.4%) and intra-day (1.7–5.0%). This research highlights the novel SiO2@π-CP adsorbent possesses the potential for addressing the enrichment of QAAs in real urine samples.