A method an system is disclosed for the detection and/or allocation of at least one point mutation in target DNA and/or RNA duplexes. The method comprises obtaining a functionalized surface which is coated with probe DNA and/or RNA whereto target DNA and/or RNA duplexes are attached, contacting said functionalized surface to an electrolytic solution having a neutral pH in a flow cell and measuring a first impedance value within said electrolytic solution, and then adding a chemical to the electrolytic solution which is able to achieve denaturation of the target DNA and/or RNA. The method further comprises measuring a second impedance value within the flow cell after completion of the denaturation of the DNA and/or RNA target, and then obtaining a value representative for the impact of the chemical on the impedance of the electrolytic solution. The amount and/or allocation of point mutation(s) within the target DNA and/or RNA is then determined by calculating the denaturation-time constant based on the difference between the first and second impedance value and taking into account the impact of the chemical by third impedance value.