Determination of trace rhodamine B by spectrofluorometry and magnetic solid phase extraction based on a 3D reduced graphene oxide composite

Abstract

Magnetic solid phase extraction based on a 3D reduced graphene oxide composite coupled with spectrofluorometry was proposed to determine the presence of trace rhodamine B in chili powder and tap water. The characterization results showed that Fe₃O₄ covered the surface of the 3D reduced graphene oxide (3D-RGO) composite. The adsorption behaviour and adsorption capacity of the 3D-RGO composite were investigated. Several significant factors that affect the adsorption and desorption performance were optimized. The proposed method gave a wide linear range, from 0.025 to 150 μg L⁻¹ with R² = 0.9991, and low limits of detection (3S_b) and quantification (10S_b) of 0.0074 μg L⁻¹ and 0.025 μg L⁻¹ (n = 3), respectively. Furthermore, this method was successfully applied to determine the amount of rhodamine B in real samples, and the recoveries at three different spiked levels (0.03, 10, and 20 μg L⁻¹) were in the range of 95.66–99.98%, with a relative standard deviation of less than 2.01% (n = 3).