Molecularly imprinted electroluminescence switch sensor with a dual recognition effect for determination of ultra-trace levels of cobalt (II)

A dual selection/recognition effect is described for cobalt (II) ions (Co2+). It is based on bovine serum albuminmetal-Co2+ coordination (BSA-Co2+) and the use of a molecularly imprinted polymer (MIP). An electro-chemiluminescence (ECL) switch sensor was designed for detecting nanomolar levels of Co2+. The BSA-Co2+ coordination complex was chosen as a template to prepare a MIP modified switch sensor. The coordination reaction between BSA and Co2+ provides the first step in recognition, and MIP provides the second step for Co2+. This leads to a strong improvement in selectivity of the sensor. A multi-walled carbon nanotube/Cu nanoparticles/carbon quantum dots nanocomposite (MWCNT/Cu/C-dots) acts as an ECL device, and the BSA-Co2+ complex quenches the ECL signal. Therefore, the elution and resorption of BSA Co2+ can be used as a switch to control ECL. Additionally, a method was established to detect Co2+, with the detection limit as low as 3.07 x 10(-10) mol/L. The method was applied to the analysis of spiked environmental water, soil samples, and agricultural products. The recovery rates of the method were in the range of 87.5-111.3%.