Determination of non-steroidal anti-inflammatory drugs in water samples by solid-phase microextraction based sol–gel technique using poly(ethylene glycol) grafted multi-walled carbon nanotubes coated fiber

[Display omitted] ► A new, simple and sensitive method for determining NSAIDs was proposed. ► SPME based on sol–gel technology was proposed for the determination of NSAIDs. ► PEG-g-MWCNTs was used as stationary phase to prepare the sol–gel SPME fiber. ► This method has a considerably low LOD and a relatively wide linear rang. In this study, poly(ethylene glycol) (PEG) grafted multi-walled carbon nanotubes (PEG-g-MWCNTs) were synthesized by the covalent functionalization of MWCNTs with hydroxyl-terminated PEG chains. PEG-g-MWCNTs was used as a novel stationary phase to prepare the sol–gel solid-phase microextraction (SPME) fiber in combination with gas chromatography–flame ionization detector (GC–FID) for the determination of ibuprofen, naproxen and diclofenac in real water samples. Some parameters which influencing the extraction efficiency were such as desorption temperature and time, extraction temperature and time, pH, salt effect and stirring speed that were investigated and optimized. Under the optimal conditions, the method detection limits (S/N=3) were in the range of 0.007–0.03ngmL−1 and the limits of quantification (S/N=10) between 0.05 and 0.07ngmL−1. The relative standard deviations (RSDs) for one fiber (repeatability) (n=5) were obtained from 5.9 up to 8.1% and between fibers or batch to batch (n=3) (reproducibility) in the range of 7.2–9.1%. The developed method was successfully applied to real water samples while the relative recovery percentages obtained for the spiked water samples at 0.2ngmL−1 were from 84 to 107%.