Electrochemiluminescence sensor for pentoxifylline detection using Au nanoclusters@graphene quantum dots as an amplified electrochemiluminescence luminophore

The Au nanoclusters@graphene quantum dots nanocomposite as an electrochemiluminescence (ECL) luminophore was synthesized through amide coupling reaction between Au nanoclusters (Au NCs) and graphene quantum dots (GQDs). The ECL intensity of the as-prepared Au NCs@GQDs was enhanced for 2.6-fold compared with that of Au NCs or 40-fold compared with that of GQDs, which was due to the ECL resonance energy transfer between GQDs as a donor and Au NCs as an acceptor, and excellent electrical conductivity of GQDs. In addition, the synergistic effect likewise improved stability of the ECL signal. A type of “signal-off” solid-state ECL sensor for detection of pentoxifylline was fabricated based on the selective quenching effect of pentoxifylline on the ECL signal of Au NCs@GQDs in alkaline medium. The sensor showed excellent sensitivity and wide linearity for pentoxifylline determination in the range from 7.0 × 10 −7 to 1.2 × 10 -4 mol/L with the detection limit of 9.0 × 10 -8 mol/L (S/N = 3). The proposed method was successfully applied for pentoxifylline detection in pharmaceutical tablet with satisfactory results.