Bromine speciation by a paper-based sensor integrated with a citric acid/cysteamine fluorescent probe and smartphone detection

The present work reports on a sensitive and affordable non-instrumental method for the determination of bromine species in environmental waters by combination paper-based headspace sampling smartphone-based fluorescence detection. proposed approach takes advantage luminescence quenching probe (5-oxo-3,5-dihydro-2 H-thiazolo[3,2-a]pyridine-7-carboxylic acid, TPCA) derived from natural compounds, namely, citric acid cysteamine, when exposed to molecular bromine. decreased intensity was attributed formation dibrominated derivative TPCA at detection area analytical device (PAD). Remarkably, PADs modified with luminescent showed excellent stability. Under optimal conditions, limits 5.4 µg L-1 0.9 Br- BrO3-, respectively, repeatability lower than 10% both species. validated against two certified reference materials, namely BCR-611 BCR-612 (low high level groundwater), successfully applied analysis water samples recoveries range 93–106%.