Study on the Rapid Determination of Neophytadiene Content in Tobacco by NIR Spectroscopy

PurposeTo explore a rapid method for determining the content of neophytadiene in flue cured tobacco leaves which was based on near infrared spectrum (NIR).

MethodNear infrared technology combined with spectral pretreatment (multiple scattering correction + second derivative + Norris smoothing), abnormal sample removal (module iterative singular sample diagnosis), wavelength optimization based on competitive adaptive weighting (CARS) algorithm, and model wavelength variable optimization based on RMSECV with cross-validation root mean square error (RMSECV) were used. A near infrared PLS calibration model for neophytadiene content in flue-cured tobacco leaves was established. The accuracy and stability of the model was verified by internal parameters (R² of calibration model), RMSECV, RMSEC and RMSEP of external verification set and their paired t-test results.

Results(1) The main wavelength ranges of the calibration model are 2 464.58-2 450.60 nm, 1 962.7-1 959.74 nm, 1 767.37-1 763.76 nm, 1 687.98-1 681.41 nm, 1 425.36-1 419.90 nm, 1 412.93-1 409.86 nm, 1 180.66-1 177.98 nm, 1 174.78 -1 173.18 nm, 1 168.95-1 167.37 nm and 1 156.44-1 154.38 nm. (2) The value of RMSEC is 18.602. The value of R² is 0.882 7 were used to calibrate the near infrared calibration model of neophytadiene in flue-cured tobacco leaves. The prediction error of external validation set is 20.995. The paired t-test results between the predicted and measured values of 20 external verification sets show that there is no significant difference between the two groups at the level of alpha 0.05.

ConclusionThe internal parameters and external validation results show that the calibration model has good prediction accuracy. The above results show that the method can quickly and accurately determine neophytadiene in flue-cured tobacco leaves, and has good practical value.