A rapid solid-phase extraction coupled with HPLC method for sensitive determination of NSAIDs in water samples using hierarchical porous carbon flowers

Pre-oxidation‑carbonization regulated PAN-derived porous carbon flowers, preventing collapse and enabling N/O co-doping. • PCF-400's 400 °C carbonization retains active sites, enhancing adsorption efficiency of NSAIDs. • PCF-400 exhibits superior NSAIDs selectivity, high NSAIDs adsorption (Qe ≥ 12.69 mg g −1 ) and fast kinetics (5 min equilibrium). Flower-shaped porous carbons are attractive in separation science. Herein, the controlled synthesis of porous carbon flowers (PCF) was realized by pre-oxidation and carbonization treatments of flower-shaped polyacrylonitrile (PAN) particles. The pre-oxidation treatment at 230 °C transferred the linear polymer chain of PAN to six-membered ring structure, enhancing the thermal stability to avoid the collapse of flower-shape in carbonization process. Then, the subsequent carbonization promoted the crosslinking and formation of alicyclic and graphitic structures. The carbonization at moderate temperature (400 °C) enabled the remaining of some oxygen-containing groups and the formation of nitrogen-doped carbon structure, which was responsible for the improved adsorption efficiency for non-steroidal anti-inflammatory drugs (NSAIDs). In addition, higher adsorption efficiency of PCF than that of porous carbons in other morphologies for NSAIDs was demonstrated. The PCF carbonized at 400 °C (PCF-400) showed sufficient adsorption capacity (12.69–18.59 mg g −1 ) and selectivity for NSAIDs. An SPE-HPLC method based on PCF-400 was proposed for extraction and analysis of trace NSAIDs in environmental water samples. The SPE-HPLC method showed a wide linear range (1–400 ng mL −1 ) and low detection limits (0.38–0.56 ng mL −1 ) for three kinds of NSAIDs. The intra-day and inter-day relative standard deviations (RSDs) of this method were 1.85%–2.77% and 3.17%–3.63%, respectively. The recoveries of NSAIDs in spiked samples ranged from 89% to 103% by the SPE-HPLC method. This study not only provides a simple synthetic method for preparing carbon materials with controllable morphology and adjustable heteroatom content, but also offers an analytical method for detection of trace NSAIDs in complex environmental matrices. Download: Download high-res image (126KB) Download: Download full-size image