Rapid quantification of constituents in tobacco by NIR fiber‐optic probe
Gabrielle Fernanda Zimmer, Roberta Oliveira Santos, Iberê Damé Teixeira, Rosana de Cássia de Souza Schneider, Gilson Augusto Helfer, Adilson Ben da Costa
Abstract
Abstract This study aims to develop, evaluate, and optimize the application of near‐infrared spectroscopy (NIR) autosampler device equipped with a fiber‐optic probe associated with chemometric methods for the fast quantification of routine chemical constituents such as total alkaloids, reducing sugars, nitrate, and ammonia in tobacco. For this purpose, an NIR autosampler device with capacity for 40 samples was used. The spectra were collected in the range of 950 to 2,500 nm, with three spins on the sample, a 3.0‐cm 2 sample scanning area, and 2.0 ± 0.2 mm distance between the fiber‐optic probe and the sample. Four partial least‐squares (PLS) models were developed, and different preprocessing methods were investigated. The predicted results were compared with those obtained from the reference method (continuous‐flow analysis), and root mean square error of prediction values of 0.31%, 1.27%, 0.47%, and 0.026% were obtained for total alkaloids, reducing sugars, nitrate, and ammonia, respectively. The proposed method performed well for the analysis of total alkaloids and reducing sugars with an appropriate goodness‐of‐fit and fair precision. In conclusion, considering the performance of the regression models and the associated environmental and economic advantages, the application of NIR spectrometer autosampler device equipped with a fiber‐optic probe associated with a PLS and synergy interval PLS algorithms cannot replace the reference method, but it is a promising tool for tobacco monitoring.