In these papers Raman Spectroscopy is used to study the interaction of microbicide N-Alkyl-N, N-dimethyl-N-benzylammonium chloride (Benzalkonium Chloride or Barquat–80) with metallic íons. The technique Surface Enhanced Raman Scattering applies to this purpose. This technique applies to the study of the interaction of this compound with Human Serum Albumin (HSA). The observed changes in the spectrum indicate that the alkane chain and the – CH3 or - CH2 radicals of barquat attack HAS and the interaction with HSA and Barquat is on the aromatic ring too. Very important features of benzalkonium salts are their bactericidal and antimicrobial properties.