重铬酸钾-DNS比色法测定发酵液中乙醇含量

Potassium Dichromate-DNS Colorimetric Determination of the Content of Ethanol in the Fermentation Broth

发酵液中往往含有一些还原性物质,如葡萄糖等,用经典的重铬酸钾氧化比色法来测定发酵液中乙醇含量时,往往出现结果偏大的现象.为了测定发酵液中乙醇含量,在经典重铬酸钾氧化比色法基础上,使用DNS氧化比色法测定葡萄糖含量,修正乙醇含量的测定结果.统计分析发现,经改良的重铬酸钾-DNS比色法测定含葡萄糖的乙醇标准溶液时相对误差均值为0.95%,远小于传统的重铬酸钾氧化比色法的相对误差均值18.07%,在精密度相似情况下提高了准确度,更适宜用于测定含葡萄糖等还原性成分的发酵液中乙醇含量.

Because the fermentation broth often contains some reducing substances, for example glucose, when we use the classic potassium dichromate oxidation colorimetric determination of the content of ethanol in the fermentation broth, the result is often too large. In order to determine the content of ethanol in the fermentation broth, using DNS oxidation colorimetric to measure the glucose content on the basis of the clas- sic potassium dichromate oxidation colorimetrie can correct the ethanol content of the measured results. The statistical analysis shows the relative average error of the improved potassium dichromate-DNS colorimetric measurement of glucose-containing ethanol standard solution is 0.95%, much smaller than 18.07%, the rela- tive average error of the conventional .potassium dichromate oxidation eolorimetric. It improves the accuracy in the case of similar preeisiofa, so it＇s more suitable for the determination of the ethanol content in the fer- mentation broth containing glucose and other reducing ingredients