The development of DNA-modified electrodes for the determination of lead cation is described. The performance of anionic (AQMS) and cationic (methylene blue) redox markers for this aim is compared. It is shown that the use of anionic marker results in a significantly better analytical parameters, as compared to measurements with cationic marker. The optimized sensor distinguishes itself with high selectivity towards lead cation and lower detection limit of 0.42 10(-8) mol dm(-3). The interaction between lead ion and DNA strands were studied using electrochemical impedance spectroscopy (EIS) and surface plasmon resonance with imaging (SPRi). (C) 2015 Elsevier Ltd. All rights reserved.