Study of Microemulsion Composition Effect over Phosphorescence Emission of a Polycyclic Aromatic Compound

A detailed characterization of the microemulsion composition is necessary to make the phosphorimetry suitable as powerful analytical methodology. Four microemulsion systems (hexane/ n -butanol/SDS/water, hexane/ n -pentanol/SDS/water, hexane/3-pentanol/SDS/water, and hexane/ n -hexanol/SDS/water) were studied, establishing the oil/water (O/W) microemulsion composition with best phosphorimetric characteristics (maximum phosphorescence intensity and minimum stabilization time). The different experimental variables that affect the phosphorimetric emission of the model compound selected named fluoranthene (i.e. concentrations of micellar agent, heavy atom, and oxygen scavenger) were carefully optimized and an analytical method for this analyte was proposed. The best results (maximum sensitivity and rapidity) were obtained using the hexane/ n -pentanol/SDS/water system with a 0.03% v/v of hexane and 0.05% v/v of n -pentanol, 0.92% v/v of SDS (0.5 M). Under these conditions, it is possible to observe an instantaneous phosphorescent signal of fluoranthene and develop a method with a detection limit of 2.2 ng mL m 1 and a relative standard deviation of 1.53% at a concentration level of 25 ng mL m 1.