A Selective Spectrofluorometric Determination of Micromolar Level of Cyanide in Water Using Naphthoquinone Imidazole Boronic-Based Sensors and a Surfactant Cationic CTAB Micellar System

We developed a new spectrofluorometric method for qualitative and quantitative determination of cyanide in water using the incorporation of naphthoquinone imidazole boronic-based sensors (m -NQB and p -NQB) and a cationic surfactant, certyltrimethyl ammonium bromide (CTAB). This micellar system exhibited great selectivity for cyanide detection with an assistance of the cationic surface of micelle. The interaction of boronic acid of the sensor toward cyanide in CTAB micellar media gave a quantitative measure of cyanide concentration in the micromolar level. Under the optimal condition, fluorescence intensity at 460 nm of m -NQB and p -NQB provided two sets of linear ranges, 0.5-15 mu M and 20-40 mu M and the limit of cyanide detection of 1.4 mu M. Hence, both sensors in CTAB aqueous micellar system offered a considerably promising cyanide detection with 1000-fold enhancement of the detection limit compared to those studied in DMSO: H2O. The proposed sensors could also be used to determine cyanide in water with good analytical characteristics.