Pyrocatechol violet impregnated magnetic graphene oxide for magnetic solid phase microextraction of copper in water, black tea and diet supplements

Pyrocatechol violet impregnated magnetic graphene oxide hybrid material (PV-MGO) was prepared as magnetic solid phase microextraction for separation and preconcentration of copper before its determination by flame atomic absorption spectrometry. PV-MGO hybrid material was characterized using field emission scanning electron microscope (FE-SEM, SEM-Mapping), scanning transmission electron microscopy (STEM), energy dispersive X-ray (EDX), Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD) and Raman spectroscopy. Effects of various parameters such as pH, eluent type, vortex time, amount of magnetic adsorbent were investigated. Under the optimized conditions the MSPE-FAAS procedure presents limit of detection (LOD) of 4.0 μg L⁻¹, limit of quantification (LOQ) of 13.3 μg L⁻¹, preconcentration factor of 20 and relative standard deviation (RSD) 4.93%. The accuracy of the method was confirmed by the analysis of the certified reference materials (NCS ZC73032 Celery, CRM025-050 metals on soil, TMDA-64.2 fortified water) and addition-recovery tests. The present method was successfully applied to water, black tea and diet supplements.