Determination of Starch in Tobacco by Ultrasonic Extraction and Continuous Flow Method

To determine starch in tobacco fast and accurately,the colorimetric method was improved as following:1) the interferential substances in sample were removed by ultrasonic extraction at room temperature in place of extraction in heated water-bath;2) the starch in tobacco was extracted at room temperature with ultrasonic instead of static extraction;3) the starch in tobacco extract was determined by a continuous flow autoanalyzer in place of a spectrophotometer.The improved method was compared with the colorimetry.Starch contents in 15 domestic flue-cured tobacco samples and 15 commercial cigarette samples were determined with the improved method,and the results showed that the recoveries of starch were from 97% to 100% with the coefficient of variation of 1.58%.The starch contents determined with the improved method and a continuous flow autoanalyzer were slightly higher than those with the colorimetry and spectrophotometry,respectively.The starch contents in C3F of K326 from different growing areas of the same crop year differed obviously,while the starch contents in domestic Virginia type cigarettes were basically identical,which were higher than imported blended type cigarettes by about one percentage point.The method is suitable to fast analysis of starch in tobacco.