Removing DC trends before calculating power spectral densities is a necessary operation, but the choice of the method is probably one of the most difficult problems in electrochemical noise measurements. The procedure must be simple and straightforward, must effectively attenuate the low frequency components without eliminating useful information or create artifacts. Several procedures will be presented, including moving average removal, linear detrending, polynomial fitting, analog or
digital high-pass filtering, and their effect on electronic and electrochemical signals discussed. The results show that the best technique appears to be polynomial detrending On the contrary, the
recently proposed moving average removal method was found to have considerable drawbacks and its use should not be recommended.
Keywords: electrochemical noise, voltage drift, current drift, moving average removal, high-pass filtering, noise resistance, power spectral density, corrosion monitoring.