Perylene Tetracarboxylate Dye Based Colorimetric and Fluorometric Sensor for ppb-Level Fluoride Detection in Water

Abstract

Fluoride contamination in water is a serious global concern, demanding advanced sensing and quantitative monitoring methodologies. Many existing fluoride sensors are limited to detecting fluoride ions in organic mediums, but here, a novel approach using a perylene tertacarboxylate dye (K4PTC MOF) offers a solution. This method employs colorimetric and fluorescence signals to detect fluoride ions in 100% water, showcasing high sensitivity, selectivity, and reversibility. The method primarily involves addition of AlCl3 to the K4-PTC solution, resulting in diminished fluorescence, accompanied by a visible colour change. Subsequent addition of fluoride to the aforesaid solution triggers fluorescence restoration and colour reversal, forming the basis of fluoride ion sensing. The fluorescence intensity and absorbance exhibit linear correlation with fluoride concentrations, enabling precise detection with remarkably low limits of detection of 0.2 ppm and 1 ppb for UV-Vis and fluorescence technique respectively. This sensing methodology is successfully applied to detect of fluoride in ground water samples collected from fluoride affected areas, highlighting its potential for rapid and accurate environmental monitoring and public health protection.