Amino-terminated hyper-branched polyamidoamine polymer grafted magnetic graphene oxide nanosheets as an efficient sorbent for the extraction of selective serotonin reuptake inhibitors from plasma samples

In this study, third generation dendrimers covalently bonded to magnetic graphene oxide nanosheets (DMGO) were prepared. Taking advantage of its large surface area, excellent biocompatibility and abundant functional groups, DMGO was used as an ideal sorbent for the preconcentration and determination of four important selective serotonin reuptake inhibitors (citalopram, sertraline, fluvoxamine and fluoxetine). The successful synthesis of DMGO was confirmed using Fourier-transform infrared spectroscopy (FT-IR), field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM) and X-ray diffraction (XRD). The factors that affect the extraction process, such as pH, amount of sorbent and extraction time, were optimized using central composite design (CCD) and desirability function (DF) methods. The intra-day precisions (RSD%) were lower than 4.91% and the method displays a wide linear range. The limits of detection for citalopram, sertraline, fluvoxamine and fluoxetine in aqueous samples are 0.3, 0.3, 0.6, and 0.9 ng mL(-1), respectively. The technique was applied to determine selective serotonin reuptake inhibitors (SSRIs) in plasma samples and gave recoveries higher than 89%. Finally, the sorbent was reused 20 times without a significant decrease in extraction recovery.