Molecularly imprinted electrochemical luminescence sensor based on signal amplification for selective determination of trace gibberellin A3.

A new molecularly imprinted electrochemical luminescence (MIP-ECL) sensor was developed for Gibberellin A3 (GA3) determination. This sensor is based on competitive binding between the GA3 and the Rhodamine B (RhB)-labeled GA3 (RhB-GA3) to the MIP film. After the competitive binding, the residual RhB-GA3 on the MIP was electro-oxidized to produce RhB oxide, which could greatly amplify the weak electrochemiluminescence (ECL) signal of luminol. The ECL intensity decreased when the RhB-GA3 was replaced by GA3 molecules in the samples. Accordingly, GA3 was determined in the concentration range from 1 × 10(-11) to 3 × 10(-9) mol/L with a detection limit of 3.45 × 10(-12) mol/L. The sensor shows high sensitivity and selectivity, wide response range, good accuracy, and fast response. Beer samples were assayed by using the sensors, and the recoveries ranging from 96.0% to 103.2% were obtained.