Comparison of methodologies for separation of fungal isolates using Fourier transform infrared (FTIR) spectroscopy and Fourier transform infrared-attenuated total reflectance (FTIR-ATR) microspectroscopy

- Methods of preparation of samples resulted in varied FTIR and FTIR-ATR spectra.
- FTIR/FTIR-ATR spectra of various fungi share many features with minute differences.
- Peak absence from fungal FTIR/FTIR-ATR spectra is as important as their presence.

Twenty distinct fungal isolates were analysed using three methods of sample preparation for FTIR spectroscopy and FTIR-ATR microspectroscopy to test for differences in surface chemical composition between living and dried fungal samples, as well as differences between surface chemistry and overall chemistry of homogenized dried samples. Results indicated that visually the FTIR spectra of different fungi are remarkably similar with subtle discernable differences, which statistical analysis of the spectra supported. Within each data set, different fungal isolates were responsible for statistical differences. Lack of congruence between each of the methods used suggests that determination of chemical composition is highly dependent upon the method of sample preparation and analysis (surface vs. whole) applied.