Identification of selected CITES-protected Araucariaceae using DART TOFMS

Abstract

Determining the species source of logs and planks suspected of being Araucaria araucana (Molina) K.Koch (CITES Appendix I) using traditional wood anatomy has been difficult, because its anatomical features are not diagnostic. Additionally, anatomical studies of Araucaria angustifolia (Bertol.) Kuntze, Araucaria heterophylla (Salisb.) Franco, Agathis australis (D.Don) Lindl., and Wollemia nobilis W.G.Jones, K.D.Hill & J.M.Allen have reported that these taxa have similar and indistinguishable anatomical characters from A. araucana. Transnational shipments of illegal timber obscure their geographic provenance, and therefore identification using wood anatomy alone is insufficient in a criminal proceeding. In this study we examine the macroscopic appearance of selected members of the Araucariaceae and investigate whether analysis of heartwood chemotypes using Direct Analysis in Real Time (DART) Time-of-Flight Mass Spectrometry (TOFMS) is useful for making species determinations. DART TOFMS data were collected from 5 species (n =75 spectra). The spectra were analyzsed statistically using supervised and unsupervised classification algorithms. Results indicate that A. araucana can be distinguished from the look-alike taxa. Another statistical inference of the data suggests that Wollemia nobilis is more similar and within the same clade as Agathis australis. We conclude that DART TOFMS spectra can help in making species determination of the Araucariaceae even when the geographic provenance is unknown.

Chemical differentiation of Bolivian Cedrela species as a tool to trace illegal timber trade

“…These discrimination errors are higher compared with previous studies that applied DART-TOFMS, which reached discrimination errors of less than 10% for species discrimination (Lancaster and Espinoza, 2012;Musah et al, 2015;Evans et al, 2017) and of ~30% in distinguishing between sites of origin (Finch et al, 2017). We also found strong differences in discrimination error between species.…”

“…The principal ionization mechanisms for DART-TOFMS have been thoroughly discussed and it has been used to identify timber species with an accuracy of 70% to 95% (Lancaster and Espinoza, 2012;Evans et al, 2017). To describe the chemotaxonomic relationship of our Cedrela samples, mass spectra were acquired using a DART ion source (IonSense, Saugus, MA, USA) coupled to a JEOL AccuTOF time-of-flight mass spectrometer (JEOL USA, Peabody, MA, USA) in positive ion mode.…”

Comparison of species classification models of mass spectrometry data: Kernel Discriminant Analysis vs Random Forest; A case study of Afrormosia (Pericopsis elata (Harms) Meeuwen)

“…Heartwood slivers are placed directly in a stream of heated helium gas, produced by the DART ion source. Spectra were acquired in positive ion mode with the DART ion source parameters and mass spectrometer settings as defined in Evans et al, McClure et al, Lancaster and Espinoza, and Espinoza et al The spectra were obtained over the mass range of m/z 50–700. The text files of the mass‐calibrated, centroided mass spectra were exported using TSS Unity (Shrader Software Solutions, Inc., Grosse Pointe Park, MI, USA) data reduction software and used for further analysis.…”

“…Each specimen is assigned to a class in the grouping variable (in this case species), and KDA then calculates the maximum separation between species classes in a training set. This is then mapped in the nonlinear higher‐dimensional space . KDA determines the species separation based on a subset of appropriate ions.…”

“…Recent research has focused on the identification of plant species ( Mitragyna speciosa (Korth.) Havil and Datura ), discrimination among selected CITES‐protected Araucariaceae , and differentiating coastal from inland populations of Douglas fir ( Pseudotsuga menziesii (Mirb.) Franco) using Random Forest classification algorithms .…”