Characterizing biological macromolecules with attenuated total reflectance-Fourier transform infrared spectroscopy...

Infrared (IR) spectra of biologically derived materials display distinct absorption bands correlating to individual macromolecules: protein, polysaccharide, lipid, and nucleic acids. A series of experiments aimed at teaching qualitative bioorganic spectroscopy using attenuated total reflectance (ATR) Fourier transform infrared (IR) with biological polymers as samples is proposed. Labs targeting 1st and 4th year undergraduate students at St. Francis College are being developed. During 2014 ➔ 2017, an integrated biology/chemistry exercise featuring elementary spectroscopy as an addition to an existing lab on light microscopy was administered to three sections of a 1st year general biology course. Students were taught the concept of a spectral fingerprint and to identify carbohydrate and protein based materials by looking for key vibrational bands. The success of that effort as determined by the results of an assessment quiz became the motivation for developing an advanced 4th year exercise involving four macromolecules. In a trial lab (Spring 2019) students gathered reference spectra from materials homogeneous in a single biopolymer followed by spectra of whole tissues which they were expected to fully characterize. Assessment data suggest that 1st year students benefited most from the experience. A detailed discussion of reference and sample spectra (as obtained by students) and relevant bond vibrations along with suggestions for instructors are presented.