Heuristic correlation of rheological measurements and Electrochemical Impedance Spectroscopy (EIS) of the DNA/water system.

In this work, it is reported viscosity, density, sound velocity and electrochemical impedance spectroscopy (EIS) measurements of calf thymus DNA in aqueous solutions, in order to investigate the overlapping C* and entanglement concentrations Ce. These critical concentrations demark the conditions at which start appearing interactions and entanglements between DNA molecules in solution. EIS has been proposed as new alternative analytical techniques to obtain C* and Ce in polyelectrolyte solutions. A new parameter the characteristic time (τc) was defined, and it is obtained from a new type of log-log Bode plot using the crossover frequency (τc=1/ωc) of the real (Z’) and imaginary (Z”) components when they are plotted as a function of the frequency. Preliminary results show similar values C* and Ce by EIS to those obtained from rheological, densimetry and sound velocity measurements.