ANATEL A643, Operator'S Manual, Page: 82 / 222

82 of 220 Calibration and Validation - Anatel A643a
R
PS
-
June
20
07
-
Ed
it
io
n
12
Operator Manual
Anatel
6.2
TOC Calibration
Note:
Refer to Standard Operating Procedure (SOP) #643–1/1A for complete instructions on
performing this procedure.
Calibration ensures the accuracy of the TOC values obtained by the Anatel A643a Analyzer.
TOC values are determined by measuring the change in conductivity of a high-purity water
sample as its organic compounds are oxidized to carbon dioxide inside the instrument’s
analysis cell. The confirmation procedure subtracts the average of a series of background TOC
measurements from the average of a series of working standard measurements.
Linear regression is performed on the data and a correlation coefficient (R) for the analysis is
reported. The instrument automatically determines whether the calibration passes or fails
based on the factory calibration. If the absolute value of the percent slope change (%
SC
) of the
new calibration is
≤
15% of the factory calibration, the instrument indicates that the new
calibration has passed. If the result is >15% of the factory calibration, the Analyzer indicates
that the new calibration has failed.
Note:
It is recommended the correlation coefficient, a user-accepted (R) value, be
≥
0.990. The
calibration will not fail if the R value is
≤
0.990, only if the % slope change is not within the
specified limits.
To perform a TOC calibration:
1) With the desired Analyzer selected in any View, press the Manual Key to access its
menu selections.
2) Use the Up and Down Keys to specify Calibrations .
3) Press Enter to display its submenu.
4) Use the Up and Down Keys to specify Calibrate .
5) Select TOC Calibrate and press Enter . If the Analyzer is connected to an A-Net
network on which other instruments reside, confirm that it is the correct instrument by
verifying its serial number. The Analyzer will begin a temperature stabilization process,
its duration depending on the sample water temperature. The actual time required is
displayed and counted down.
Fig 6-1 : TOC Calibration