Selective and sensitive detection of cyanate using 3-amino-2-naphthoic acid-based turn-on fluorescence probe.

The cyanate anion (CNO), formed spontaneously within cells from urea and carbamoyl phosphate, usually functions as a biomarker of some diseases such as chronic kidney disease. Therefore, accurate determination of CNO is highly demanded. Herein, a 3-amino-2-naphthoic acid-based "turn-on" fluorescence probe was developed for specific detection of CNO. Upon the addition of sodium cyanate, the weak-fluorescent 3-amino-2-naphthoic acid could react with CNO, which triggered intense emission of green fluorescence. And up to 9-fold fluorescence enhancement was observed. The fluorescence enhancement ratios displayed a good linear relationship with the concentrations of CNO in the range of 0.5-200 μM. The high selectivity and sensitivity for CNO detection were investigated with the detection limit as low as 260 nM. The probe was further successfully applied to determine CNO in real samples such as tap water, human urine and serum samples, which offered a promising approach in practical applications. Graphical abstract.