On-line micellar-enhanced spectrofluorimetric determination of rhodamine dye in cosmetics

A simple FI-fluorimetric analytical methodology for the continuous and sequential determination of rhodamine B (RhB) in cosmetic products has been developed and evaluated in terms of sensibility and selectivity. The influence of several surfactant solutions on RhB fluorescence signal has been studied; particular attention was paid in the aggregation behavior of RhB–SDS system. Linear response has been obtained in the range of 1.6 × 10−9 and 1 × 10−6 mol L−1, with a detection limit of 5 × 10−10 mol L−1. The novel technique provides a simple dissolution of sample, on-line filtration with sampling rate higher than 100 samples h−1 and has been satisfactorily applied to the RhB determination in commercial lipsticks.