Development of fluorescence nanosensor based on "off-on" effect of graphitic carbon nitride - gold nanoparticles system for amikacin quantification

A graphitic carbon nitride functionalized gold nanoparticles (g-C3N4/AuNPs) based fluorometric assay was developed for simple and rapid on-site amikacin determination. g-C3N4 fluorescence is reduced (turn-off) when they bind to AuNPs but recovers (turn-on) when amikacin binds to AuNPs and releases the g-C3N4. The assay is based on the effective property of AuNPs as absorbers in inner filter effect (IFE) systems. Under optimized conditions of 25 mM Na2SO4, pH 6.0, 3.0 mg mL(-1) g-C3N4, and incubation time of 12 min, the proposed method achieved a low detection limit of 5 x 10(-9) M (2.9 ppb), wide linear range from 10(-8) to 10(-6) M, high precision (RSD <5 %) and high selectivity over other ions including Ca2+, Mg2+, Fe2+, NO3-, and PO43- as well as several antibiotics, namely naproxen, levofloxacin, vancomycin, ceftriaxone, amoxicillin. The fluorometric sensor based on g-C3N4/AuNPs has produced good agreement quantifying amikacin in pharmaceutical samples, as cross-checked with LC-MS/MS method. The developed fluorometric sensor is promising for rapid on-site detection of other organic and inorganic substances with high sensitivity, selectivity, and minimal reagent consumption.