Fabrication of a GUMBOS-based ratiometric organo nanosensor for selective and sensitive detection of perchlorate ions that works in 100% water

Abstract

This work intends to develop sensitive and easily applicable ionic liquids (ILs)-based fluorimetric sensors for detecting the explosive perchlorate (ClO4-) anions in the presence of other hazards and interferents. We have designed and developed an IL-compromising pyrene butyrate anion-based fluorophoric group of uniform materials based on organic salts (GUMBOS), PBIL, from sodium pyrene butyrate and trihexyltetradecylphosphonium chloride (P66614Cl) by simple ion exchange mechanism. Using reprecipitation methods, pyrene-based water-suspended nano-GUMBOS, nPBIL, has been fabricated and characterized by numerous analytical methods. The fabricated nano-GUMBOS display bright cyan color photoluminescence due to the excimer-like emission confirmed from the color chromaticity diagram. Interestingly, due to the addition of ClO4- ions, there is a blue shift in the UV–visible absorption spectrum of the nPBIL solution with a simultaneous decrease in Mie-scattering. Consequently, there is a continuous decrease in the excimer-like emission of nPBIL with the synchronized increase in monomeric emission. We can conclude from both UV–visible absorption and emission spectra that the ClO4- ion displaces the anionic pyrene butyrate moiety of our nPBIL due to its high polarizability. The limit of detection (LOD) of the as-fabricated sensor is estimated to be 7.17 nM which is very much lower than the US Environmental Protection Agency (USEPA) predicted permeable level of perchlorate in drinking water (15 μgL−1). An efficient test kit has been fabricated and demonstrated for on-site detection of ClO4- ions in remote areas. This ion exchange-mediated substance release from such nano-GUMBOS systems is a distinctive and innovative way to design and develop efficient sensors for precisely detecting and quantifying ClO4- ions.