Free fentanyl is responsible for its pharmacological effects, but its total concentration is typically determined for therapeutic drug monitoring purposes. Determination of fentanyl concentration can help reduce the prescribed doses, leading to fewer side effects and increased effectiveness. Therefore, predicting free drug concentration in pharmaceutical research is crucial. The aim of this study was to determine free fentanyl in exhaled breath condensate. These samples were extracted using a dispersive micro solid phase extraction method with a new adsorbent made of graphene oxide, magnetic iron oxide nanoparticles, and covalent organic framework. 10 mg of the adsorbent was added to the sample solution adjusted to pH 10. After sonication for 5 min, the sorbent was separated using an external magnet. The adsorbed analyte was then eluted from the sorbent surface using a mixture of acetonitrile, methanol, and deionized water in a ratio of 42.5:42.5:15 (v/v/v) and analyzed using liquid chromatography-tandem mass spectrometry system. The calibration curve showed high linearity in the range of 0.17-10000 μg L-1 with a coefficient of determination of 0.9998 and good repeatability with a relative standard deviation of 4.1 %. Additionally, this method provided a low detection limit of 0.05 μg L-1 and quantification limit of 0.17 μg L-1.
Keywords: Dispersive solid phase extraction; Exhaled breath condensate; Fentanyl; Liquid chromatography-tandem mass spectrometry.
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