pH-mediated simultaneous and fast enrichment of NSAIDs and parabens in environmental and food samples using Schiff base network-1 functionalized magnetic sepiolite.

The simultaneous analysis of non-steroidal anti-inflammatory drugs (NSAIDs) and parabens (PBs) is critically important due to their potential risks to ecosystems and human health. However, the efficient co-enrichment of PBs and NSAIDs is quite challenging owing to the significant difference in their acid dissociation constants. Herein, a novel Schiff base network-1 (SNW-1) functionalized magnetic sepiolite nanocomposite (MSEP@SNW-1) was constructed and applied as a magnetic solid-phase extraction (MSPE) adsorbent for the co-enrichment of NSAIDs and PBs. By adjusting the sample solution to an acidic pH, both NSAIDs and PBs were converted into their molecular forms while the adsorbent was positively charged, thereby enabling their co-enrichment using a single MSEP@SNW-1 adsorbent. MSEP@SNW-1 exhibited superior adsorption capacity and rapid adsorption kinetics for all target analytes (adsorption time of 3 min). Charge-assisted hydrogen bonding, hydrophobic and π-π stacking interactions were identified as the main adsorption mechanisms. Notably, MSEP@SNW-1 possessed excellent reusability, with recoveries maintaining above 85% even after nine cycles. A sensitive analytical method was then developed by combining MSEP@SNW-1-mediated MSPE with HPLC-UV for the simultaneous quantification of PBs and NSAIDs in environmental water and milk. The established approach exhibited excellent linearity (R2 > 0.9975), high sensitivity (LODs: 0.03-0.51 μg l-1) and satisfactory spiked recoveries (80.2-108.6%). This study provides a reliable and promising strategy for trace-level monitoring of PBs and NSAIDs in complex matrices, and offers a novel concept for the design and application of functionalized materials for the simultaneous enrichment of multiple classes of analytes.