Magnetic solid phase extraction of trace paracetamol and caffeine in synthetic urine and wastewater samples by a using core shell hybrid material consisting of graphene oxide/multiwalled carbon nanotube/Fe3O4/SiO2

A new hybrid material was synthesized including magnetic graphene oxide/multiwalled carbon nanotube core shell (GO/MWCNT/Fe3O4/SiO2) and used as magnetic solid phase extraction adsorbent for separation and pre concentration of paracetamol and caffeine subsequent detection by high performance liquid chromatography. The morphology, composition, and properties of the synthesized hybrid material was characterized by Fourier transform infrared spectrometry, Raman spectrometry, X-ray diffraction spectrometry, scanning electron microscopy, mapping photographs and BET surface area analysis. The experimental variables on the extraction efficiency were studied and optimized. The optimum conditions for quantitative extraction of paracetamol and caffeine were obtained as of adsorbent amount, 70 mg; pH, 8.0; and elution with 1 mL of methanol by vortex mixer for 60s. Validation experiments showed that the developed method had good linear ranges 5-800 ng mL(-1) for caffeine and 10-1000 ng mL(-1) for paracetamol, respectively. The limits of detection were found as 1.48 and 3.32 ng mL(-1) for caffeine and paracetamol, respectively. The accuracy of the developed magnetic solid phase extraction method was proved by addition-recovery tests by using model solutions and the developed method was successfully applied for the determination of paracetamol and caffeine in synthetically prepared urine and waste water samples.