Application of diffuse reflectance infrared Fourier transform spectroscopy for the detection of bacterial biomarkers in dry corrosion deposits

Infrared spectroscopy (IR) may be used to indicate the presence of microorganisms in various deposits including these formed inside the drinking water distribution systems (DWDSs). The aim of this study was to examine the presence and intensity of absorption bands characteristic for dipicolinic acid (DPA) and other biomarkers of bacteria which probably formed biofilms in old, naturally dried deposits collected from corroded steel and cast iron pipes. The diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) was used to examine the presence and intensity of absorption bands that are characteristic of biomolecules deriving from bacterial cells. Our results showed a different chemical composition of deposits collected from various fragments of pipes and the presence of the microorganisms residues. We showed the possibility of using the DRIFT technique for rapid determination of biological contamination of dry corrosion deposits present in DWDSs. Analysis of the IR spectra second derivatives enabled for the precise determination of absorption maxima that were used to indicate the presence of amides, polypeptides, and fatty acids.