Improved performance of wrinkled CoNi-LDHs via in situ immobilization onto cotton gauze for solid phase extraction of non-steroidal anti-inflammatory drugs

Abstract

Solid phase microextraction (SPME) based on advanced composites as stationary phase is an effective technical means to preconcentrate trace analytes from environment samples. Here, a wrinkled cobalt nickel-layered double hydroxide arrays was successfully fabricated via in situ growing on polydopamine-coated cotton gauze (CoNi-LDH@PDC). Thanks to the wrinkled morphology of CoNi-LDH, the anion exchange rate and adsorption capacity of the fabricated composite were remarkably improved. The morphology of the fabricated CoNi-LDH@PDC composite was characterized by scanning electron microscopy, and the interaction between the adsorbent and analytes were analyzed by Fourier transform infrared spectroscopy. Then, a piece of 2 × 3 cm modified cotton gauze was packed into a pipette tip for simultaneous extraction and concentration three kinds of non-steroidal anti-inflammatory drugs (NSAIDs) including ketoprofen, fenbufen and ibuprofen, following analysis through high-performance liquid chromatography. Potential factors affecting the SPME process were studied in detail. Under the optimized conditions, the developed method exhibited excellent performance as the detection limits of 0.075, 0.18 and 0.17 μg L−1, besides the linear range of 0.20–3000, 0.50–200 and 0.50–3000 μg L−1 for ketoprofen, fenbufen and ibuprofen, respectively. The recoveries for spiking 5, 20 and 100 μg L−1 NSAIDs in tap water and drinking water samples were 77.3–92.4% and 82.6–95.6%, respectively. Moreover, the proposed SPME column was stable enough for 30 days experiments of extraction and desorption without obvious loss of extraction efficiency.