Dispersive Micro-Solid-Phase Extraction using Graphene Oxide/Polydopamine-Polyacrylamide Nanocomposite Coupled with HPLC-UV for Determination of Phenobarbital in Plasma Samples

Graphene oxide/polydopamine-polyacrylamide nanocomposite was synthesized by a simple method and  used  as  adsorbent for  dispersive  micro-solid-phase  extraction of phenobarbital  in  plasma samples.  The adsorbent  was  characterized  by  Fourier-transform  infrared  spectroscopy,  X-ray diffraction, scanning electron microscopy–energy dispersive spectroscopy and thermal gravimetric analysis. The  results show  that functionalization of graphene  oxide  by  polymeric  materials  can enhance  the  sorption  properties  and  thermal  stability  of the  prepared  adsorbent.  Influential parameters on  the extraction  efficiency  of Phenobarbital  including  adsorbent  amount,  elution solvent and its volume, sorption and desorption times and pH of sample solution were investigated and optimized. Under the optimized conditions, limits of detection and quantitation values were 1.4 and 5ng/mL, respectively. Relative recovery data for several real samples were obtained within the range of 84.0-98.0% with a relative standard deviation less than 7.2%. The proposed method was successfully applied to quantitative determination of phenobarbital in plasma samples.