Rapid Spectrophotometric Analysis of the Chemical Composition of Tobacco: Part 2: TotaI AIkaloids

This paper illustrates the potential of a computerized spectrophotometer for measuring total alkaloids in tobacco. Prediction equations were developed for three optical parameters. Of the three parameters investigated d² (log (1/R)) /d/² gave the best results and d R / R d l gave better results than log (1/R), where reflectance R is the ratio of the detector signal of the sample to the detector signal of the ceramic standard in the reflectance mode. The coefficient of determination r² for the prediction equation containing d² (log (1/R)) /d/² terms at 10 different wavelengths was 0.975. This equation predicted the total alkaloids in an independent set of samples with a standard error of 0.438 %. Instrument noise contributed 43 % of the variation, the remainder was attributed to anomalies of the chemical methods.