2 reagent blank values, 3 standard adjustment (user calibration), Reagent blank values – YSI pHotoFlex Series User Manual
Page 7: Standard adjustment (user calibration)
pHotoFlex
®
Series
Practical part
7
ba76126e01
03/2013
1.3.2
Reagent blank values
The evaluation of the photometric measurement always refers to the
comparison value of a sample without the substance to be determined
(reagent blank value). Thus the influence of the basic absorbance of
the reagents on photometric measurement is compensated for.
In practice, measurement of the reagent blank value is carried out with
the same amount of deionized water instead of sample.
Default reagent blank
values
For most tests, the reagent blank value is a constant value. It was de-
termined in the factory and stored in the photometer. You can, howev-
er, measure the reagent blank value yourself. The default reagent
blank value is then overwritten. The default reagent blank values are
restored when the photometer is reset to default settings.
Reagent blank values
without factory
default
For some tests, it does not make sense to store a default reagent blank
value in the factory, e.g. if a change of certain test elements during the
storing period cannot be excluded. In this case, a reagent blank value
has to be determined before the first measurement with a new photo-
meter. The photometer informs you if no valid reagent blank value is
available. The measured reagent blank value remains stored in the me-
ter until a new reagent blank value is determined. When the photo-me-
ter is reset to default, all reagent blank values that were not stored in
the factory are erased.
Note
You can increase accuracy if you determine the reagent blank value
with a test of a newly started reagent package and use the reagent
blank value for all tests of this package.
1.3.3
Standard adjustment (user calibration)
The pHotoFlex
®
pH and pHotoFlex
®
STD photometers provide the
standard adjustment function. With this function you can adjust the fac-
tory-set calibration curve for some tests in order to optimize the accu-
racy if necessary. The standard adjustment especially compensates for
lot specific deviations and age-related influences on the reagents.
For which tests the standard adjustment can be used is given in the
L