Magnetic Graphene Oxide Modified with a Surface-Active Ionic Liquid for Ultrasound-Assisted Solid-Phase Extraction (UA-SPE) to Preconcentrate Lenalidomide from Human Plasma with Determination by High-Performance Liquid Chromatography with Ultraviolet Detection (HPLC-UV)

A new magnetic graphene oxide (MGO) composite was developed as an adsorbent for the preconcentration of lenalidomide (LND) by ultrasound-assisted solid-phase extraction (UA-SPE) prior to determination by high-performance liquid chromatography with ultraviolet detection (HPLC-UV). The adsorbent was fabricated through chemical functionalization of a new surface-active ionic liquid (SAIL), i.e. 1-methyl-3-(trimethoxysilyl propyl)-imidazolium dodecyl sulfate (TMES-Im-DS) on MGO. The synthesized material presented the benefits of excellent adsorption for LND. The characterization of the synthesized functionalized magnetic nanocomposite was performed by Fourier transform-infrared spectroscopy, field emission scanning electron microscopy, Brunauer-Emmett-Teller (BET), vibrating sample magnetometry, and energy-dispersive X-ray spectroscopy. After optimization of the parameters, the limits of detection (LOD) and limit of quantification (LOQ) were 0.2 and 0.8 mu g L-1 and 0.6 and 2.5 mu g L(-1)in water and plasma samples, respectively. The enrichment factors (EFs) were from 90 to 180 in the samples. The relative standard deviation (RSD%, n = 5) as intra- and inter-day precision were from 6.3% to 7.5% and 7.1% to 8.5% in water and plasma, respectively. Lastly, the developed method presented good results for the preconcentration of LND in plasma with satisfactory repeatability.