Comparison of Different Types of Near Infrared (NIR) Instruments in Ability to Measure Alkaloids in Capsule of Poppy (P. somniferum)

Abstract

The poppy capsule is one of the most important raw materials for the pharmaceuticals industry containing in about 25 different alkaloids. Among these there are important substances, such as morphine, with analgesic and anaesthetic properties, anti-tussive codeine, and noscapine with anti-tumor activity. My first objective was comparing dispersive and Fourier transformed (FT) near-infrared (NIR) instruments in order to measure alkaloids using the same sample population via mathematical pre-treatments (i.e. gap-segment derivatives) of the spectra and partial least squares (PLS) calibrations. The best PLS calibration using cross validation (CV) was for morphine based on derivative spectra of dispersive NIR with R-square (R²) 0.924 and root mean square error (RMSE) 1.198 mg (g dry matter)^–1 in 1.24–20.44 mg (g dry matter)^–1 range. Comparison of the changes in the output of the PLS parameter for the two instruments revealed a variance depending on the derivative and the segment size.