TNPs as a novel fluorescent sensor for the selective recognition of fast green FCF: a spectrofluorimetric approach

Fluorescent tetracene nanoparticles (TNPs) have been prepared by a reprecipitation method using cetyl trimethyl ammonium bromide (CTAB) as a stabilizer. These TNPs are more photostable against photobleaching and have a high solubility in water, minimizing the utilization of hazardous organic solvents when compared with single organic fluorophores in sensing applications. The method is based on the fluorescence quenching of the TNPs, which are used as a novel fluorescent sensor for the selective recognition of the fast green FCF dye in aqueous solution. The fluorescence intensity of the TNPs was quenched by the successive addition of increasing concentrations of the fast green FCF dye. The fluorescence quenching results were found to fit the Stern-Volmer (S-V) relationship in the range of 0.5-7.0 mg L-1 with a correlation coefficient of 0.999. The limit of detection (LOD) was 0.136 mu g L-1. Moreover, the excited state lifetime of the TNPs remains unchanged even after increasing the concentration of the fast green FCF dye, which suggests that the fast green FCF dye was adsorbed over the surface of the nanoparticles to form a non-fluorescent ground state complex i.e. the nature of the quenching process is static. The proposed method was successfully applied for the quantitative analysis of the fast green FCF dye in commercial samples with no necessity of prior separation of analyte molecules from the interfering constituents.