Dispersive liquid-liquid microextraction coupled with surface enhanced Raman scattering for the rapid detection of sodium benzoate

Medicine safety has become a large concern and prompts an urgent need to develop a rapid, simple and sensitive analytical method, which can monitor excessive preservatives in medicine. In this work, dispersive liquid-liquid microextraction (DLLME) was combined with surface enhanced Raman scattering (SERS) for a quick analysis of a kind of preservatives, sodium benzoate, in ibuprofen oral solution. The experimental parameters affecting DLLME were systematically investigated. Under the optimal conditions, the whole procedure, including DLLME and the SERS analysis, could be carried out within 10 min. A good linearity between the concentration of sodium benzoate ranging from 10 to 500 mg L−1 and the SERS signal intensity could be obtained, and the correlation coefficient (R2) 0.9986. The method detection limit was 0.56 mg L−1. The relative standard deviation was less than 6.33% for ten replicates at the same sample concentrations. The analytical results prove that the method is suitable for rapid determination of sodium benzoate in ibuprofen oral samples.