Editor’s Note: The following study from Forensic Science International is highly relevant to CRE’s upcoming presentation at the FDA’s risk assessment workshop on tobacco leaf constituents. Cross-posted from the Counterfeit Cigarette Study Forum.
From: Forensic Science International
Kim Quayle, Graeme Clemens, Tamar Garcia Sorribes, Hannah M. Kinvig, Paul G. Stevenson, Xavier A. Conlan, Matthew J. Baker
Highlights
- FTIR and XRF are useful analytical techniques for tobacco identification.
- Elemental profiles highlight Ca, Cl, K and Fe as indicators of tobacco provenance.
- FTIR identifies a highly discriminative tobacco spectral fingerprint region.
Abstract
The recognition of differences between regulated large-scale mass manufactured products and the uncontrolled cultivation of tobaccos for illicit purposes plays a significant role within identification of provenance. This research highlights X-ray fluorescence and Fourier transform infrared spectroscopy as useful analytical techniques for the rapid identification of tobacco samples of unknown provenance. Identification of key discriminative features within each technique allowed for the development of typical characteristic profiles for each type of tobacco. Analysis using X-ray fluorescence highlights chlorine, potassium, calcium and iron as key elemental indicators of tobacco provenance. Significant levels of chlorine seen within Snüs samples prompted attempts to visualise chlorine containing regions and structures within the sample. Scanning electron microscopy images showed crystalline structures visible within the Snüs tobacco, structures which Energy dispersive X-ray spectroscopy qualitatively confirmed to contain chlorine. Chloride levels within Snüs samples were quantified using ion chromatography with levels found to range between 0.87 mg mL1 and 1.28 mg. Additionally, FTIR indicated that absorbances attributed to carbonyl stretching at 1050 1150 cm1, alkane bending at 1350 1480 cm1 and amide I stretching at 16001700 cm1 highlighting a spectral fingerprint region that allowed for the clear differentiation between different types of tobaccos using PCA analysis, but was limited by differentiation between provenance of cigarettes and hand rolled tobacco. X-ray fluorescence and Fourier transform infrared spectroscopy yielded different information with regards tobacco discrimination and provenance, however both methods overall analysis time and cost reduced indicating usefulness as potential handheld analytical techniques in the field.
