Studies On Chemical Analysis Of Tobacco By Near-infrared Spectroscopy Technique

The project has probed into the application of near-infrared spectrum technology in analyzing the main chemical elements in flue cured tobacco, provided the analyzing method of controlling tobacco quality rapidly and precisely with lower cost, shorter time and higher efficiency. The project has also defined and optimized the parameter of near-infrared spectrum analysis. The basic measurement parameter of analyzing tobacco elements by near-infrared spectrum is: spectral area is 4000-10000 cm^-1, resolution ratio is 8cm^-1, scanning times is 64. The experiment has defined that the accuracy of measuring objective by near-infrared spectrum equals 1.3-1.5 times of that of chemical value. The method of establishing model of measuring chemical value by near infrared has been defined. The 4 main elements near-infrared quantitative analysis model of total sugar, reducing sugar, nicotine and total nitrogen in cured tobacco, and 7 main elements of total sugar, reducing sugar, nicotine, total nitrogen, chlorine, potassium and starch in growing leaf were established. A demonstration test of the established quantitative analysis model by predicting the unknown samples shows that the average relative error between predicted value and actual value is: total sugar 3.65%,reducing sugar 2.80%,nicotine 4.25% and total nitrogen 3.18% in cured tobacco, total sugar 4.78%,reducing sugar 5.64%,nicotine 3.96%,total nitrogen 3.07%,chlorine 18.60%,potassium 6.01% and starch 6.67% in growing leaf. The satisfactory results indicated that the model of quantitative analyzing main chemical elements in cured leaf and growing leaf meets the analysis requirements and proves to be practically valuable. Compared with circulating analysis and artificial analysis, near infrared analysis will reduce costs and enhance efficiency.