GE Analytical Instruments ©2009 145 of 236 DLM 90488-01 Rev. A
9. When prompted, remove the Calibration Blank from the IOS System, insert the TOC
Calibration Standard (as KHP), and press Next.
10. When prompted, remove the TOC Calibration Standard (as KHP) from the IOS System, insert
the IC Calibration Standard (as Na
2
CO
3
), and press Next.
11. After the IC Calibration Standard (as Na
2
CO
3
) has been analyzed, the calibration summary
screen is displayed. The Analyzer indicates if the calibration passed or failed based on the
following criterion:
• The % Diff for the IC standard is ±10% or less.
If this condition is satisfied, press Apply to accept the calibration and continue.
If this condition is not satisfied, press the Cancel button to reject the calibration. You may
need to perform the calibration procedure again. However, first consult the chapter called
“Troubleshooting” on page 195 to determine if there is a problem with the Analyzer.
Percent difference is calculated as follows:
The Expected TC Concentration equals the Certified TOC Concentration of the standard,
plus the measured TOC Concentration in the Calibration Blank, plus the Measured IC
Concentration of the standard.
Expected IC is the measured value, with the lamp off, from the TC channel for the IC
standard, using the new TC calibration. The summary screen also displays the measured
values using the existing calibration, the difference between measured and expected
values and the values that would be obtained using the new calibration values (adjusted
values).
Note: If you want to manually calculate the calibration formulas for your records, you must print
the Data History and the Calibration Constants from the Analyzer before and after
performing the new calibration, in order to have access the values of the TC Slope and IC
Slope.
% Diff =
Measured Concentration - Expected Standard Concentration
Ex
ected Standard Concentration
-----------------------------------------------------------------------------------------------------------------------------------------------------------------
100
×
TCexp = TOCstd + TOCblank + ICstd
ICexp = (TCreported+ TOCoffset)
New TCslope
Old TCslope
----------------------------------
× TOC offset–
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