Engineering a new polypyrrole-modified cotton fiber for enhanced stick microextraction and sensitive monitoring

Nonsteroidal anti-inflammatory drugs (NSAIDs) are ubiquitous pharmaceutical contaminants frequently detected in aquatic environments and medicinal products, raising increasing concerns regarding their chronic ecological toxicity and potential human health risks through long-term exposure. However, accurate exposure assessment of NSAIDs is often hindered by their trace-level occurrence and strong matrix interferences in complex samples. To address these analytical challenges, this study created a new polypyrrole-modified cotton fiber via a controlled oxidative polymerization process, leading to the construction of a fiber-supported stick microextraction (FS-SME) device. Owing to the synergistic contribution of π–π interactions, hydrogen bonding, and pseudo‑hydrogen bonding, the sorbent materials exhibited exceptional mechanical stability and a high adsorption capacity toward NSAIDs (up to 45.25 mg/g). Adsorption kinetics and isotherm analyses revealed that the enrichment process was dominated by rapid monolayer chemisorption, ensuring efficient and reproducible extraction. Under optimized conditions, the FS-SME-HPLC method provided satisfactory recoveries (62.6%–75.4%), low detection limits (0.2–2.5 ng/mL), and excellent linearity (R 2  ≥ 0.992) within a 5 mL sample system, while also exhibiting good reusability and batch-to-batch consistency. Overall, this work introduced a new cotton fiber functional material and delivered a reliable device for risk-informed environmental monitoring of NSAIDs in complex matrices, thereby supporting risk management and regulatory decision-making for pharmaceutical contaminants.