LAR Process Analysers QuickTOC ultra - Calibration Standards - TOC-Direct Method; Tconly Method; Stock Solution - TOC-Direct Method; Tconly Method

12E5119 Instruction Manual QuickTOC
®
ultra
IECEx 85
6 Reagents and Calibration Standards
6.2 Calibration Standards
LAR | PROCESS ANALYSERS AG
6.2.2 Calibration Standards - TOC-Direct Method / TConly Method
This section explains how you can prepare the calibration standards for the TOC-Direct Method and
TConly Method yourself.
First, a stock solution needs to be prepared which can then be diluted to arrive at the calibration standard
concentration required.
6.2.2.1 Stock Solution - TOC-Direct Method / TConly Method
This section shows how to prepare a stock solution for TOC-Direct Method and TConly Method
analogous to DIN EN 1484:1987.
Chemicals required:
• 2.125 g Potassium hydrogen phthalate (C
8
H
5
KO
4
) p.a. dried for 2 hours at 105°C
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:
• TOC (Total Organic Carbon) = 1,000 mg/l C
Notice
To minimise mistakes, LAR always recommends using the stock solution as
the initial solution for dilutions.
The stock solution can be used as a calibration standard.
The stock solution dilutions can be used as a calibration standard.
Warning
The stock solution can be kept in a sealed glass bottle for about four weeks at
a temperature of 4°C.
Please note that the pipetting accuracy can be negatively impacted when the
stock solution is diluted.
i
!