Travoprost (TRV) is an efficient prostaglandin (PG) analogue, which is hydrolyzed by corneal esterases to its
active acid form (TRV acid) after absorption. Till now no spectrofluorimetric methods have been reported for
detection of TRV acid in biological fluids. Due to high sensitivity, simplicity and rapidity; a novel and ultrasensitive
spectrofluorometric method with an efficient solid phase extraction (SPE) technique was developed
for determination of TRV acid in aqueous humor (AH). The study relies on the fluorescence enhancement of
nitrogen-doped carbon dots (N-CDs), which were prepared via a hydrothermal treatment of triphenylamine and
citric acid. The formed nanoprobe responds with very high sensitivity to trace amounts of TRV acid through
hydrogen bonding formation, which is accompanied by an enhancement in fluorescence intensity due to N-CDs
aggregation. The proposed method showed excellent sensitivity for analyzing TRV acid in the range of 1–200 ng/
mL, with a very low limit of detection (0.29 ng/mL). Additionally, the method’s selectivity for analyzing TRV
acid in the presence of common ions and anticipated co-administered drugs was assessed. The structural and
chemical properties of the prepared N-CDs were extensively characterized using X-ray diffraction (XRD), Fourier
transform infrared (FT-IR) spectroscopy, Transmission electron microscopy (TEM), High resolution transmission