Abstract: PSX-5 Expandable Ion Analyzer and 501 Ammonia Gas Sensing Electrode were used to direct measurement of equilibrium electric potential at pH>12. The repetition of the same electrode potential was poor, thus was affected the precision of analysis. The experiment determined double standard solutions and samples, then used linear regression and Described working Curve determined Nitrogen Content of Amino acid oral liquid. The result shows that the method is exact、quick、 simple and convenient, and accuracy and precision is very ideal.

Key words: Ammonia Gas Sensing Electrode, Amino acid oral liquid, Total Nitrogen