English abstract
Reduced graphene oxide/magnetite composites (RGO-M) based dispersive magnetic solid
phase extraction was used for extraction and quantification of non-steroidal anti inflammatory drugs in camel urine samples. High performance liquid chromatography
(HPLC) equipped with mass spectroscopy (MS) was employed for separation and
determination of the preconcentrated samples. The NSAIDs compounds were: flunixin,
diflunisal, celecoxib, deracoxib and etoricoxib. The properties and morphology of the
synthesized adsorbent were characterized by Fourier transform-infrared spectroscopy (FT IR), scanning electron microscopy (SEM) and X-ray diffraction (XRD). Several parameters
influencing the extraction efficiency of the investigated analytes such as the extraction time,
the amount of graphene/Fe3O4, the sample pH, the elution solvent and elution solvent amount
were evaluated and optimized. Under the optimized experimental conditions, the figure of
merit results showed an excellent linear dynamic range (0.1– 4 µg mL-1
), with coefficient of
variation (R2
) higher than 0.998 and limits of detection (LOD) between 0.07 and 0.20 ng mL 1
. The recovery percentage of the analytes were between 72% and 102 % and the intra- and
inter-day relative standard deviations (RSD%) were less than 11%. Moreover, MS/MS
conditions were optimized in positive and negative modes. Parallel reaction monitoring
(PRM) was used to determined precursor ion and product ions of the NSAIDs compounds.
The developed method was validated and the proposed method was applied successfully to
the determination of NSAIDs in real camel urine samples.
