Analytical control of Rhodamine B by SERS using reduced graphene decorated with copper selenide

A novel approach for the decoration of reduced graphene oxide with copper selenide (CuSe-rGO), using supercritical carbon dioxide (sc-CO₂) as a medium, was developed and proposed as a new substrate for surface-enhanced Raman spectroscopy (SERS) to determine Rhodamine B in chili powder. The synthesized materials graphene oxide (GO), reduced graphene oxide (rGO) and CuSe-rGO were characterized by Raman spectroscopy, X-ray diffraction (XRD) and scanning electron microscopy (SEM). All SERS spectra were obtained by using a portable Raman spectrometer. The procedure presented involves a simple and rapid sample pretreatment in order to determine Rhodamine B in chili powder, with a limit of quantification of 44.5 ng g^-1. The recovery values of the proposed method resulted in the 96% to 99% range, with RSD values from 2.4% to 3.0%. The developed SERS active hybrid substrate has an enhancement factor higher than those using gold or silver nanoparticles, providing a clear improvement in the sensitivity.