82 User Manual QuickTOC
®
purity
ATEX 2 04E3920
6 Reagents and Calibration Standards
6.1 Reagents LAR | PROCESS ANALYSERS AG
6.1.6.1 Stock Solution - TOC-Difference Method
This section shows how to prepare a stock solution for TOC-Difference Method analogous to
DIN EN 1484:1987.
Chemicals required:
• 6.382 g Potassium hydrogen phthalate (C
8
H
5
KO
4
) p.a. dried for 2 hours at 105°C
• 4.415 g Sodium carbonate (Na
2
CO
3
) dired for 1 hour at 185°C
• 3.500 g Sodium hydrogen carbonate (NaHCO
3
) dried for at least 24 hours in the exsiccator with
silica gel
Proceed as follows:
1. Dissolve the weighted sample of each of the three substances in a 1,000 ml graduated flask in 700
ml of deionised water.
2. Fill the 1,000 ml graduated flask up to the mark with deionised water.
The concentration of this stock solution is:
• TC (Total Carbon) = 4,000 mg/l C
• TIC (Total Inorganic Carbon) = 1,000 mg/l C
• TOC (Total Organic Carbon) = 3,000 mg/l C
Warning
The stock solution can be kept in a sealed glass bottle for about four weeks at a tem-
perature of 4°C.
Please note that the pipetting accuracy can be negatively impacted when the stock so-
lution is diluted.
!
To Next Page
Loading...