β-cyclodextrin functionalized CdTe quantum dots for electrochemiluminescent detection of benzo[a]pyrene

β-cyclodextrin (β-CD) functionalized CdTe quantum dots (QDs) were prepared with β-CD and mercaptopropionic acid (MPA) as the stabilizers (denoted as β-CD-MPA-CdTe). The QDs capped with the dual stabilizers, β-CD and MPA, not only showed improved electrochemiluminescence (ECL) efficiency and higher ECL intensity due to the effective removal of the nonradiative surface state and deep surface trap of the QDs, but also exhibited selective response toward benzo[a]pyrene (BaP) as a consequence of specific host-guest interaction between the β-CD and BaP, resulting in decreased ECL of the QDs. On the basis of the quenching effect of BaP on the ECL of β-CD-MPA-CdTe QDs, a sensitive and selective method for the determination of BaP was developed. Under optimal conditions, a linear range from 87 pM to 10 nM with a detection limit of 29 pM (S/N = 3) was obtained for the detection of BaP.