A green solid-phase method for preparation of carbon nitride quantum dots and their applications in chemiluminescent dopamine sensing

Abstract

A facile, green and one-step synthesis strategy towards highly fluorescent g-CNQDs via solid-phase pyrolyzing melamine and EDTA at low temperature was proposed. The obtained g-CNQDs can produce strong chemiluminescence (CL) in the presence of K₃[Fe(CN)₆]. The mechanism of the g-CNQDs–K₃[Fe(CN)₆] CL system was investigated by using CL, UV-Vis absorption, IR, fluorescence and electron spin resonance (ESR) spectrum. The CL emission was probably from the radiative recombination of oxidant-injected holes and the thermally excited electrons in g-CNQDs. The established new CL system was successfully applied to determinate dopamine in the range of 1 × 10⁻⁸ to 2 × 10⁻⁶ M with a detection limit of 4.7 nM (S/N = 3). The protocol was validated by analyzing serum samples with excellent sensitivity and good recoveries. The new CL system offered a valuable insight for the properties of luminescent g-CNQDs in CL field, and opened a new avenue for its practical applications.