Graphene quantum dot-enhanced chemiluminescence through energy and electron transfer for the sensitive detection of tyrosine

Graphene quantum dots (GQD) could significantly enhance the chemiluminescence (CL) reaction of Ce(IV) with NaHSO3 through energy and electron transfer. The chemiluminescence resonance energy transfer (CRET) occurred between SO2*/O-1(2) and GQD, and radiative electron-hole annihilation came from the combining of the hole-injected GQD (GQD(center dot+)) and electron-injected GQD (GQD(center dot-)). Tyrosine (Tyr) is easily oxidized by OH center dot and Ce(IV), which results in the decrease of OH center dot and Ce(IV), and the CL intensity of the GQD-Ce(IV)-NaHSO3 system is inhibited by Tyr. In this way, the GQD-based CL as a sensitive and selective method was applied for the detection of Tyr in the range 0.02-8.00 mu M with the detection limit of 4.0 nM. The method was applied to the determination of Tyr in food samples with satisfactory results.