Calibration Method - Endress+Hauser analytikjena multi N/C UVHS Operating Manual

Function and design
3.5.3

Calibration method

TC/NPOC
TIC
TOC
28
Each parameter (TC, TOC, TIC, etc.) of a method can be calibrated in the multiWin soft-
ware. Not all parameters require calibration, however.
You can store up to three calibration functions for different concentration ranges for
each parameter in a method. The software automatically assigns the measurement re-
sults to the correct calibration range.
The software determines the calibration function in relation to mass m per injected
sample. It determines linear or quadratic calibration functions in accordance with the
following equations via regressive calculation:
Linear calibration function: c = (k
Quadratic calibration function: c = (k
c: target concentration of the standards
V: Sample volume
I : Net integral
Net
k , k , k : calibration coefficient
0 1 2
The net integral is the raw integral corrected by the blank value of the preparation wa-
ter.
You can specify the regression type (linear or quadratic). Individual measuring points or
measured values for the calculation of the current calibration (manual outlier selection)
can be selected. If necessary, you can define individual standards again, or also add ad-
ditional measurement points to the calibration.
Up to 20 calibration points can be used, with a tenfold determination per calibration
point. The calibration function can be determined either from the average values of the
repeat measurements or from all individual determinations.
The TC channel is calibrated directly for the TC parameter, and after sample purging for
the NPOC parameter.
The concentration c is proportional to integral I
TC
The TIC channel is calibrated.
The following applies: c
TIC
The calculated parameters appear in the method in the TIC analysis channel. The calcu-
lation of the analysis results is based on the calculated calibration function.
The TOC is determined with the differential method (TOC Diff). Generally, separate cali-
bration functions are determined for the TC and TIC channels.
The calculation of the analysis results is based on the calculated calibration functions for
TC and TIC. The TOC content results from the following formula:
c = c – c
TOC TC TIC
The parameters appear in the TIC and TC analysis channels in the method.
The TC and TIC parameters can be calibrated simultaneously. The use of mixed standard
solutions such as carbonate/hydrogen carbonate and potassium hydrogen phtalate or
sucrose is recommended for this.
The TIC and TC channels can also be calibrated consecutively with separate standard so-
lutions. This is useful if different ranges are to be calibrated for the TC and TIC channels.
x I + k )/V
1 Net 0
2
x I + k x I
2 Net 1
: c
TC
= f(I )
TIC
multi N/C UVHS, multi N/C pharma UV
+ k )/V
Net 0
= f(I ).
TC TC