Electro-Chemical Devices (ECD) CA6 Hardness Analyzer - Manual (Page 30)

3) Sample Function #1 or #2 Loop Off / Loop On
With the Sampling function, the sample pump is activated and the pinch valve (to drain) is closed.
De-Ionized water (#2) is used to fill the colorimetric cell after passing through the loop.
Loop On, the loop pathway is open. This releases the sample contained inside the loop to mix with
the DI water (#2) passing through the loop, In this way the sample quantity trapped in the loop
during the Rinse Cycle is mixed with DI water and transferred to the colorimetric cell for the
colorimetric analysis.
Loop Off, the loop pathway is closed and liquid does not pass through the loop. Sample 1 picture
shows the sample function with sample connected to #1 and loop on or off.
After the dilution, the colorimetric reaction is performed.
3.2 Oxidation/Digestion Module
For the detection of some parameters (for example TP, TN, NO
3
...) it is necessary to perform a
photochemical oxidation or digestion before the colorimetric reaction. In these cases the Oxidation
Module option is added to the Liquids section.
To ensure a complete oxidation of the sample, the oxidation can be performed using sulfuric acid, heat,
UV irradiation and/or a chemical oxidizer.
DANGER!
Below is a list of possible hazards to be considered when the oxidation / digestion module is included
in a CA-6 analyzer:
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