Voltammetric determination of adenine, guanine, and DNA using liquid mercury free polished silver solid amalgam electrode
Liquid mercury free polished silver solid amalgam electrode (p-AgSAE) proved experimentally a suitable substitute for the hanging mercury drop electrode in cathodic stripping voltammetric (CSV) analyses of purine bases and of acid treated DNA. The analyses are done in alkaline solution in the presence of copper(II) ions. With p-AgSAE using direct current voltarnmetry (DCV) the limits of detection for purine bases as well as for two types of DNA were on nanomol level. Low levels of RSD (1-3%. n = 11) of repeated measurements confirmed that the used mode of electrochemical regeneration of p-AgSAE was sufficient, and it provided reliable measurement results. The mentioned working electrode is suitable for a sensitive electrochemical detection of acid-hydrolyzed DNA, and may be applied in DNA hybridization assays as an alternative to working electrodes based on liquid mercury [hanging mercury drop electrode (HMDE), meniscus AgSAE].