Disclosed herein is a more sensitive and accurate method of monitoring the pH of a solution, wherein the pH of the solution is quantified as a function of the electrochemical response of the solution in a two or three-electrode electrochemical cell, wherein the solution comprises a compound capable of undergoing a change in its oxidation state and/or structural conformation as a function of the pH of the solution. Also disclosed are highly accelerated methods and processes enabling analysis of specific polynucleotide sequences in a sample, e.g. a biological sample. The methods disclosed herein are, for example, useful for rapid screening of a large amount of samples in a point-of-care setting.