English
11
Operation
4.3.4 Performing the matrix correction
Note:
Take laboratory value measurements or reference values promptly
or, alternatively, take these from the stabilized sample. This will prevent
changes in sample concentration, as time is a factor in comparative tests.
Refer to
7.3 Validation accessories, Page 39
for recommended
laboratory measurement tests.
4.3.4.1 1-point matrix correction
Proceed as follows to perform
1-point matrix correction
:
1.
Select
SENSOR MENU > AN-ISE SC
or
AISE SC
or
NISE SC >
CALIBRATION > 1-point matrix correction
.
2.
Select
2-point matrix correction
from the selection window and
press
ENTER
.
3.
Select the parameters you wish to correct and confirm by
pressing
ENTER
.
Selection options for AN-ISE sc:
NH
4
+ NO
3
; NH
4
; NO
3
; NH
4
+ K; NO
3
+ Cl; NH
4
+ K NO
3
+ Cl
Selection options for AISE sc:
NH
4
; NH
4
+ K
Table 1 Correction options for ISE probes
Correction option
Application
1-point matrix
correction
A 1-point matrix correction is the
most commonly used correction option
and performs a 1-point
matrix correction for ammonium and/or nitrate (
). It is advisable to perform a 1-point
matrix correction as
the first correction
. The 1-point matrix correction can be performed both with
and without correction of the compensation electrodes (potassium or chloride); in most cases, it is
sufficient to perform it without correction. A correction featuring potassium and/or chloride is only
necessary if a high level of accuracy is required. With a 1-point matrix correction, a sample must be
taken when the correction is triggered and analyzed in the laboratory. The 1-point matrix correction is
activated when the laboratory value is entered.
1-point value
correction
1-point value correction (correction at one concentration point) corresponds to a 1-point matrix
correction
with an alternative entry format
.
Comparison values between the ISE probe and the laboratory can be collected over a period of
around a week with this correction. The correction can be performed at a later stage.
2-point value
correction
2-point value correction (correction at 2 different concentration points) should be performed if
dynamic
concentration fluctuations are present over at least half a decade
1
and a 2-point
matrix correction or 1-point value correction does not achieve a sufficiently accurate result
.
Comparison values between the ISE probe and the laboratory can be collected over a period of
around a week with this correction. The correction can be performed at a later stage.
2-point matrix
correction
The
2-point matrix correction corresponds to a 2-point value correction, but uses an
alternative entry format
and is recommended if there is a dynamic process with a large
nitrate/ammonium fluctuation greater than at least half a decade
1
. With a 2-point matrix correction, a
sample must be taken for both points when the correction is triggered and analyzed in the laboratory.
The 2-point matrix correction is activated when the laboratory value is entered.
Previous corrections
Return to one of the last matrix and value corrections performed
if a correction has not produced
a successful result
.
1
Examples of half a decade: The concentration of nitrogen nitrate shifts between 1 and 5 mg NO
3
–N or
between 5 and 25 mg/L NO
3
–N. (conc2 = (conc1 x 10)/2)
Calibration
Matrix correction
More corrections
Information
Summary of Contents for AISE sc
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