Molecularly imprinted Ni-polyacrylamide-based electrochemical sensor for the simultaneous detection of dopamine and adenine.

Molecularly imprinted polymer (MIP) membranes prepared in situ present several advantages: they maintain the original morphology, adhere strongly to the collector, and exhibit a controllable structure. In this study, a Ni-polyacrylamide (PAM)-MIP matrix was fabricated in situ on glassy carbon via the one-step electro-polymerization of AM monomers in the presence of Ni and template molecules. Ni2+ ions were introduced as oxidants to promote AM polymerization and bulking agents to fabricate a three-dimensional porous PAM-MIP matrix. The Ni-PAM-based MIP sensor exhibited a quantitative dual response toward dopamine (DA) and adenine (Ade) in the pH range of 5.0-9.0. The linear concentration range changed depending on the pH environment, and the concentrations of DA and Ade ranged from 0.6 to 200 μM and from 0.4 to 300 μM, respectively. The ranges of detection limits (S/N = 3) were 0.12-0.37 μM for DA and 0.15-0.36 μM for Ade. In addition, the dual-MIP sensor exhibited high reliability in the detection of DA and Ade in human serum owing to its excellent anti-interference ability and long-term stability. The technique developed in this study is expected to facilitate the construction of multi-target response electrochemical biosensors and the reliable determination of small molecules with high selectivity and stability.