A method is provided for measuring a concentration of dibasic acid in a substance in a gas cleaning process, the method comprising the steps of sending a plurality of voltage pulses through the substance by a first electrode (21) and a second electrode (30), which first and second electrodes (21, 30) are in contact with the substance, receiving current responses generated by the plurality of voltage pulses, and analyzing the current responses using a multivariate data analysis for calculation of the concentration of dibasic acid in the substance. Also provided is a dibasic acid sensor (10, 202), control unit (50, 202a) and analysing unit (60, 202b) for performing such a method.
