Fourier transform infrared photoacoustic spectroscopy (FTIR-PAS) was applied to nineteen fish species in Brazil's Upper Paraná River basin to identify differences in the structural composition of their scales. To differentiate the species, a canonical discriminant analysis was used to indicate the most important absorption peaks in the mid-infrared region. Significant differences were found in the chemical composition of scales among the studied fish species, with Wilk's lambda = 5.2 × 10<sup>−6</sup>, <i>F</i><sub>(13,18,394)</sub> = 37.57, and <i>P</i> < 0.001, indicating that O-CH<sub>2</sub> wag at 1396 cm<sup>−1</sup> can be used as a biomarker of this species group. The species could be categorized into four groups according to phylogenetic similarity, suggesting that the O-CH<sub>2</sub> 1396 cm<sup>−1</sup> absorbance is related to the biological traits of each species. This procedure can also be used to complement evolutionary studies.
Vol. 7, Iss. 9 Virtual Journal for Biomedical Optics
Francylaine S. Almeida, Sandro M. Lima, Luis H.C. Andrade, and Yzel R. Súarez, "Differentiation of Neotropical Fish Species with Statistical Analysis of Fourier Transform Infrared Photoacoustic Spectroscopy Data," Appl. Spectrosc. 66, 782-785 (2012)