测定酱油中氨基酸态氮国家标准方法的改进及其在本科实验教学中的应用

Modification and Application of the National Standard Method in Undergraduate Laboratory Experiment for Determining Amino Acid Nitrogen in Soy Sauce

国家标准采用电位滴定法测量酱油中氨基酸态氮含量用以评价酱油的质量,具有设备简单、操作方便的优点,但应用于本科基础教学实验尚存在困难,如氢氧化钠滴定剂消耗体积小,普通滴定管滴定精度差,以及采用普通pH玻璃电极进行空白校正消耗时间长等。根据基础教学实验仪器配置的条件对其进行相应的改进,改进后的方法分析时间大幅缩短,准确度和精确度都有明显提升。将国家标准引入本科教学实验能激发学生的学习兴趣,培养严谨细致的操作习惯,提高应用知识的能力,从而促进创新型人才的培养。

Potentiometric titration is employed in the national standard to measure the content of amino acid nitrogen in soy sauces for quality assessment,the method has the advantages of public availability of the instruments and easy operation.However,there are some difficulties in implementing this method in a fundamental teaching laboratory,such as small consumption volume of sodium hydroxide titrant that leads to poor accuracy and long blank calibration time using ordinary pH glass electrode.In this paper,the standard method is modified according to the apparatus available in the fundamental teaching laboratory,with the merits of shorter measuring time and enhanced accuracy and precision.Introducing national standards into undergraduate laboratory experiments can stimulate students'interests in learning,cultivate rigorous and meticulous operation habits,improve the ability of knowledge application,and promote the cultivation of innovative talents.