In order to evaluate the uncertainty in the determination of total alkaloids in flue-cured tobacco with continuous flow method,the cause-effect relationship diagram in the determination was revised and a new mathematical model for measurement uncertainty assessment was set up by analyzing the whole measurement process.The sources of measurement uncertainty,sample concentration and measurement repeatability of autoanalyzer were determined.The results showed that: the measurement uncertainty mainly come from the moisture content in sample.The standard uncertainty of measurement results was 0.05%,and the expanded uncertainty(α=0.05,k=2) was 0.10%.

The volatile alkaloid contents of one hundred eighty-two kinds of fluecured tobacco from Fujian, Guizhou, Sichuan,Shandong,He'nan,Yunnan,Liaoning,Chongqing and Hunan were studied and compared.The analytic data showed that of the upper leaves were higher than that of the middle leaves and higher than that of the lower leaves.In the same stalk position,the better the quality was the higher the content of the volatile alkaloid.The results showed that the content of the volatile alkaloid was significant difference in the different varieties,stalk position and in the different areas.The data clustered by quick clustering algorithm(QCA) also showed the same results.A reference basis was provided for studying the quality characteristic,and properly using in the cigarette blending design of every grade tobacco leaf.