Endress+Hauser CA76NA, Руководство по эксплуатации

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Product description CA76NA
12 Hauser
The pH electrode has 2 specific functions:
• It serves as the reference point for the sodium electrode.
• It measures the pH value of the sample.
To also be able to measure Na
+ in very low concentrations, the Ag + and H + activity must be
well below the Na + concentration to be measured. In this case, the pH value present must
be more than 10.8. The device is set to a pH target value of 11.00 as standard to
sufficiently safeguard the set pH value.
The pH value of the sample is increased to 11.0 by adding an alkalization reagent, e.g.
diisopropylamine.
The sensitivity of the measuring arrangement to interference ions is according to the
following rule:
Ag+ >> H+ >> Na+ > >Li+ > K+
3.2.2 Sample conditioning
Sample conditioning consists of the following main components:
• Alkalization pump
• Bottle with alkalization reagent
• Overflow vessel
• Alkalization vessel
It performs the following tasks:
• Monitors the flow of sample with a level switch in the overflow vessel
• Maintains a constant pressure through the overflow vessel to ensure constant flow
• Alkalizes the sample with pH regulation in the alkalization vessel
Purchase alkalization reagent separately (recommended: diisopropylamine (DIPA),
> 99.0 % (GC), in a bottle made from a solid material, e.g. glass).