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

The Au [email protected] 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 [email protected] 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 [email protected] 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.