Non-linear Alternated-Current (AC) spectrometry has been recently proposed [Bozzini and Sgura, Math. Prob. Eng. (in press)] as an approach able to yield basically the same results as AC impedance spectroscopy, but with a remarkably higher statistical confidence. In particular, quantitative parameter estimation problems commonly found in the analysis of AC impedance data carried out with the available methods [Sgura and Bozzini, J. Non-Lin. Mech. 40 (2005) 557], can be remarkably reduced. This paper reports the first example of the experimental implementation of the method, as applied to Cu electrodeposition from a sulphate solution containing polyethyleneglycol, a system relevant to semiconductor fabrication, previously investigated by electrochemical and spectroelectrochemical methods in our group [Bozzini et al. J. Appl. Electrochem. (in press), Bozzini et al. J. Appl. Electrochem. 36 (2006) 87].