[en] Highlights: • The XPS-excited Auger Cu LMM spectrum was proven to be characteristic. • A specific fingerprint for the Cu-adsorbate connection was found. • XPS measurements at very low take-off angles enabled fingerprint analysis. - Abstract: In this work, surface analysis by measuring high-resolution Auger Cu L₃L_4,5M_4,5 spectra was performed at very low take-off angles using X-ray photoelectron spectroscopy. The focus of this research was on determining if a fingerprint feature exists for a specific connection between Cu(I) (and/or Cu(II)) and different organic molecules. These organic molecules were adsorbed on Cu surface from 3 wt.% NaCl solution containing a 1 mM concentration of organic compound, i.e. 4‐methyl‐2-phenylimidazole, benzotriazole, 3‐amino-1,2,4-trazole, 1,2,4‐triazole, 2‐mercaptobenzimidazole, 2‐mercaptobenzoxazole, 2‐mercaptobenzothiazole, 1‐hydroxybenzotriazole, and 2-mercapto-1-methylimidazole. This feature was shown to be connected to Cu(I)- and/or Cu(II)-complex formation.