Carbon nitride quantum dot-enhanced chemiluminescence of hydrogen peroxide and hydrosulfite and its application in ascorbic acid sensing

Abstract

Herein, weak chemiluminescence (CL) reaction of hydrogen peroxide and hydrosulfite was greatly enhanced by carbon nitride quantum dots (g-CNQDs). CL experiments and electron spin resonance (ESR) investigation indicated that g-CNQD increased the production of singlet oxygen (¹O₂), superoxide radical (˙O₂⁻), and sulphite radical anion (˙SO₃⁻) in the hydrogen peroxide–hydrosulfite CL system; this could be attributed to the enhanced-CL intensity and gave us new insights into the character of fluorescent carbon nitride quantum dots. Ascorbic acid exerted an inhibition effect on the CL of the hydrogen peroxide–hydrosulfite–g-CNQD CL system. This phenomenon was utilized as a determination method of ascorbic acid in the concentration ranging from 2.85 × 10⁻⁷ to 2.85 × 10⁻⁴ mol L⁻¹, with a detection limit of 8.0 × 10⁻⁸ mol L⁻¹. Ascorbic acid in tablets and injections has been successfully detected with recoveries in the range from 96.2% to 106%.