ＰＨ测定水样的问题

水中的电解质浓度太低，使用普通的pH电极不能满足要求。可以选用适用于纯净水pH测定的专用电极。如下面的pH电极（选自瑞士万通网站，没有翻译过来）

6.0253.100 Aquatrode Plus

Ideal for aqueous, weakly buffered solutions

Precise measured values and very rapid response in ion-deficient or weakly buffered solutions – such as drinking, surface and rain water – thanks to newly developed electrode membrane glass and optimized fixed ground-joint diaphragm insensitive to contamination
Maintenance-free inner electrolyte
LL reference system with outstanding long-term stability
Variable outer electrolyte for special applications
Fixed ground-joint diaphragm insensitive to contamination