BUCHI KjelFlex K-360 - Manual (Page 28)

5 Putting into operation
28 KjelFlex K-360 Operation Manual, Version C
5 .6 Boric acid titration and back titration
The K-360 offers the possibility to work with boric
acid titration or back titration. It is recommended
to choose a permanent configuration as different
hardware is needed to convert between the two
titration methods.
Buchi recommends to work with boric acid titra-
tion.
Boric acid titration
Receiving vessel: Boric acid solution 2 % or 4 %,
adjusted to pH 4.65.
Titrant: Standardized sulfuric acid solution or hy-
drochloric acid solution
It is recommended to use boric acid solution 4 %,
adjusted to pH 4.65 and standardized sulfuric acid
solution.
The K-360 includes all necessary hardware to
work with boric acid titration. Boric acid is dosed
via the integrated pump.
Fig. 5.6: K-360 for boric acid titration (with titrator)
Back titration
Receiving vessel: Standardized sulfuric acid
Titrant: Standardized sodium hydroxide solution
An external dosage device must be connected for
the exact addition of the receiving solution. See
chapter 6.4.6 for information on the installation
and set-up of the external dosage device.
Fig. 5.7: K-360 for back titration (with external dosage device)