Mussel-inspired polydopamine-functionalized ultralight cellulose aerogel for simple and portable extraction of...

Synthetic cathinones (SCs) are drugs of abuse that act on the central nervous system, producing psychoactive effects similar to those of amphetamines. Their greater accessibility compared with the traditional amphetamine-type stimulants has contributed to their increasing popularity in recent years. The analysis of SCs in biological samples is essential for documenting their consumption. In this study, a facile, portable, cost-effective and environmentally friendly extraction procedure was proposed for the simultaneous extraction of seven SCs from urine and hair samples, using polydopamine (PDA)-modified small-columnar cellulose aerogel as the extraction medium. The prepared aerogels exhibited ultralow density, high mechanical stability and swelling behaviour, and could be easily separated and reused using a disposable pipette without causing secondary pollution. A multiple PDA self-assembly process was designed to allow uniform adhesion of PDA onto the aerogel pore walls, ensuring full contact with the SCs. This enhanced the extraction ability through synergistic hydrogen bonding, π-π stacking interactions, van der Waals forces and higher specific surface area. Batch extraction experiments were conducted to evaluate the impacts of solution pH, desorption solvent, extraction time, desorption volume and desorption time. Under optimized conditions, a dispersive-micro solid-phase extraction technique coupled with LC/MS was established, achieving low limits of detection (0.006-0.017 μg/L) and quantification (0.020-0.055 μg/L). The method yielded intra-day and inter-day relative standard deviations (n = 5) of 2.0 %-4.8 % and 3.7 %-8.1 %, respectively. Recoveries ranged from 81.2 % to 101.6 %, with negligible matrix effects (85.7 %-96.8 %). After eight consecutive cycles, the aerogel retained over 84 % of its initial extraction performance. Therefore, this green and sustainable aerogel shows strong potential for applications in forensic toxicology.