Non-Gravimetric Method For Ultra Micro Liquid Volume Measurement
LI Zhi-hao1,WANG Jin-tao1,LIU Xiang1,CHEN Chao-yun1,2,TONG Lin1,BAO Xue-song1,ZHANG Long1,LIU Zi-yong1,ZHANG Pei-man3
1. National Institute of Metrology, Beijing 100029, China
2. China Jiliang University, Hangzhou, Zhejiang 310018, China
3. Qingdao Institute of Measurement, Qingdao, Shandong 266101,China
Abstract：In order to overcome the shortcoming of significant influence of evaporation capacity on gravimetric method, and meet the requirements of online measurement, one non-gravimetric method was introduced for measuring micro liquid volume. According to Faraday law and Karl Fischer electrochemical principle, the Karl Fischer potentiometric titration method (KFCT method) is also investigated for micro liquid volume measurement, which calculates micro water content by measuring consumed electric quantity in electrolytic process, and obtains the micro liquid volume by combining liquid density. Comparing to gravimetric method, experimental systems for the non-gravimetric method was designed. The experiment indicates that the test result by using KFCT method is in good conformance with that by using gravimetric method, and meet the technical requirement of ISO 8655, but the measured value of KFCT method is a little bigger. Comparing with gravimetric method, which is low in requirement of measurement environment, easy to realize the online calibration and capable of effectively reducing the influence of liquid evaporation.
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2017, Vol. 38 
