Abstract: A new fluorescence spectrometry method for the determination of rhodamine B (RhB) was established by the use of eosin Y (EY) as fluorescent probe. In Sфrensen buffer solution at pH 6.8, the fluorescence intensity of anionic dye EY can be significantly enhanced by adding cetyltrimethylammonium bromide (CTMAB), a cationic surfactant. However, RhB has the ability to quench the fluorescence in a proportional manner within a certain concentration range. In this study, one-factor-at-a-time designs were used to determine the optimal experimental conditions for the determination of RhB. The linear range, detection limit and average recovery rate of the developed assay were 0－0.9 mg/L, 0.0016 mg/L, and 101.3%－113.7% with relative standard deviation of 2.76%－4.98%, respectively. This method is simple, quick, selective and sensitive so that it is suitable for the determination of RhB residues in fruit drink products.

Key words: fluorescent probe, eosin Y, rhodamine B, residue