This chapter presents some results that provide insight on the effect of the interactions with the metal surface, a water molecule and an external electric field, on the geometry and vibrational frequencies of adsorbed zwitterions of three amino acids: glycine, L‐alanine, and L‐serine. It reports a comparative spectroelectrochemical study of the behavior of the three amino acids with the simpler structures. The chapter focuses on the electrochemical behavior of L‐alanine and L‐serine, presenting their adsorption on gold thin‐film electrodes in acidic media. The results reported here, conclude that, for the interpretation of the experimental spectra of some adsorbed species, in particular for the assignment of bands to modes, the situation can become nontrivial, and the use of density functional theory (DFT) calculations of optimized geometries and vibrational frequencies show great help, in particular if the relevant ingredients are included in the model used for such calculations.