Conformational properties of nucleic acid fragments are strongly dependent on nucleotide sequences. The C-rich ODNs can adopt different secondary structures which are held together by hemiprotonated and intercalated cytosine base pairs (C.C+). These structures, so called i-motifs, were investigated in DNA nonamers with 6C by both electrochemical (voltammetry and electrophoresis) and spectral (absorption UV spectra and circular dichroism) methods. The application EVLS (elimination voltammetry with linear scan) procedure to the reduction signals of cytosine (C) and adenine (A) on a hanging mercury drop electrode revealed different conformations of studied nonamers.