微波消解-电导率法快速测定花叶滇苦菜中粗蛋白

建立一种快速、简便测定食品中蛋白质的方法，以郑州地区花叶滇苦菜为样品，以硝酸-过氧化氢混酸为消解剂，利用微波技术进行快速消解，将蛋白质中的氮转化为NH4＋。根据单因素试验确定中性甲醛的用量后，用中性甲醛将弱酸根NH4＋转化为强酸H＋，以NaOH标准溶液进行电导滴定。结果表明，花叶滇苦菜干基样品中粗蛋白的平均含量为20.16%，平行测定的相对标准偏差为2.5%（n=6）。与标准方法对比测定，经F检验和t检验表明这2 种测定方法无显著性差异，置信度为95%，结果令人满意。该方法具有快速、简便、准确、节省试剂、污染小、不需要指示剂等优点。

Rapid Determination of Crude Protein in Sonchus asper by Microwave Digestion-Conductivity Titration

A rapid and simple method to determine crude protein content in Sonchus asper was established in this study.
Samples were digested with nitric acid-hydrogen peroxide by microwave digestion technique to convert crude protein to
NH4+. The NH4+ generated in the digestion was further converted to H+ ions by neutral formalin for conductivity titration with
standard NaOH solution. The results indicated that the average content of protein in wild Sonchus asper from Zhengzhou
was determined to be 20.16% with relative standard deviation (RSD) of 2.5% (n = 6). Compared with the classic method,
the conductivity titration method did not exhibit significant difference as analyzed by F-test and t-test at 95% confidence
level. This method has the advantages of convenient operation, high sensitivity, quick determination, accurate results and no
requirements for indicators.