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.

[Simultaneous separation of organic acid and organic salts by electrostatic ion chromatography].

The electrostatic ion chromatographic column was prepared by coating conjugated acid salt micelles on the surface of octadecyl silica stationary phase. Pure water was used as mobile phase, and the conductance detector was connected on-line to electrostatic ion chromatograph. The conditions under which organic acid and organic salts were detected were studied. The mechanism for the above separation is discussed. Sodium benzoate and citric acid in Lichee drink were separated and determined. This method is rapid, simple with little interference and good reproducibility without any pollution since the mobile phase is water. This is an environmental friendly analytical method.