Facile Preparation of Graphene-Modified Magnetic Nanoparticles and Their Application in the Analysis of Four Anti-depressant Drugs in Plasma and Urine

Background: Anti-depressants are used to treat depression and some anxiety and personality disorders. In this study, a magnetic sorbent was prepared for the extraction of some anti-depressant drugs from plasma and urine samples. In order to extract the target compounds from the samples, magnetic Fe3 O4 nanoparticles coated with graphene were used as the sorbent.

Methods: Vibrating sample magnetometry, scanning electron microscopy, energy dispersive X-ray spectroscopy, Brunauer–Emmett–Teller nitrogen sorption/desorption analysis, Fourier transform infrared spectroscopy, and X-ray diffraction were applied to investigate the synthesized sorbent. First, an ammoniacal solution of the target compounds was exposed to the sorbent for the adsorption purpose. It was facilitated by vortexing. Then, by using an external magnetic field, the sorbent particles containing the adsorbed analytes were separated from the solution. Acetonitrile was used to desorb the analytes from the sorbent. Then, the eluate containing the analytes was separated from the sorbent in the presence of an external magnetic field, mixed with 1,1,2-trichloroethane (at µL-level), and quickly injected into the ammoniacal solution containing dissolved KCl. After centrifuging the formed cloudy solution, an aliquot of the sedimented organic phase was injected into a gas chromatograph equipped with mass spectrometer.

Results: Low limits of detection (LODs) and quantification were obtained in the ranges of 0.66- 1.03 and 2.1-3.4 ng/mL, respectively. The method led to acceptable extraction recoveries (55- 66%), high enrichment factors (214-275), good repeatability (relative standard deviation≤5.7% for intra- and inter-day precisions), and good linearities of the calibration curves (r2≥0.996).

Conclusion: The proposed method can be applied for the successful extraction of anti-depressant drugs from plasma and urine samples.