80 Instruction Manual QuickTOC
®
ultra
IECEx 12E5119
6 Reagents and Calibration Standards
6.1 Reagents LAR | PROCESS ANALYSERS AG
6.1.3 Phosphoric Acid (H
3
PO
4
) for TOC-Difference Method
1% phosphoric acid (H
3
PO
4
) is used for the outgassing or elimination of inorganic carbon compounds
(TIC), such as carbonate. The low pH value converts the ligated CO
2
(e.g. carbonate) into gas phase,
which is then gassed out of the liquid and can be determined.
Proceed as follows:
1. Fill a 5 l graduated flask with 4 litres of deionised water.
2. Add 58 ml of an 85% phosphoric acid (H
3
PO
4
).
3. Fill the graduated flask up to 5 l with deionised water.
4. Add 1 g of copper sulphate (CuSO
4
* 5H
2
O) to the solution to prevent bacteria forming.
5. Keep the phosphoric acid solution underneath the analyser (e.g. in the Reagent Cabinet or
Ambient Air Preparation Unit).
6.1.4 Hydrochloric Acid (HCl) for TOC-Direct Method (NPOC-Method)
1% hydrochloric acid (HCl) is used for the outgassing or elimination of inorganic carbon compounds (TIC),
such as carbonate. The low pH value converts the ligated CO
2
(e.g. carbonate) into gas phase, which is
then gassed out of the liquid and can be determined.
Proceed as follows:
1. Fill a 5 l graduated flask with 4 litres of deionised water.
2. Add 200 ml of a 25% hydrochloric acid (HCl).
3. Fill the graduated flask up to 5 l with deionised water.
4. Keep the hydrochloric acid solution underneath the analyser (e.g. in the Reagent Cabinet or
Ambient Air Preparation Unit).
Notice
Biological deposits can form in the stripping vessel for strongly biological sam-
ples. A sulphuric acid (H
2
SO
4
) should be used here instead of the phosphoric
acid (H
3
PO
4
) for determination of the TIC.
Please contact your local partner or the Technical Support of LAR
(Chapter 15 on page 283) before using another acid.
Notice
Hydrochloric acid concentrations between 3 and 5% can also be used depen-
ding on the application.
Please contact your local partner or the Technical Support of LAR
(Chapter 15 on page 283) before using another concentration.
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