Eppendorf BioSpectrometer kinetic - Manual (Page 81)

81
Troubleshooting
Eppendorf BioSpectrometer ® kinetic
English (EN)
The coefficient of
determination for
the regression
evaluation of the
standard series is
< 0.8. • For methods with evaluation of standard
series via the regression procedure: If the
regression evaluation for the standard
series was nonlinear, but the standard
evaluation was accepted by the user, a
warning appears after samples have been
measured.
 Use the sample results with the
reservation mentioned or repeat
the measurement of the standard
series and samples.
Scan: Some of the
measured
absorbances are
too high and are
not displayed. • For at least one scan wavelength, the
absorbance exceeded the measuring
range.
• Turbidity of the measuring solution.
• Measurements at the limits of the
photometric measuring range.
 If the non-displayed areas of the
scan are relevant: Dilute the
sample or remove the dilution via
centrifugation and repeat the
measurement.
The measurement
is not complete. • Kinetic procedure: You have prematurely
canceled the measurement using the
[Stop] softkey. If at least 2 measuring
points are available, a result is calculated
and displayed.
 Accept the measuring result with
the reduced measuring time or
measure again with a longer
measuring time.
The kinetics are
nonlinear: The
coefficient of
determination is
< 0.95. • Kinetic procedure with "linear
regression" measuring procedure: The
coefficient of determination for the
regression evaluation indicates a
significant deviation of the measuring
points from the regression line.
• Turbidity of the measuring solution.
• Measurements at the limits of the
photometric measuring range.
• Activity concentration of the enzyme too
high.
 Accept measuring result or
remeasure the sample. Before
repeating the measurement,
evaluate the reason for the
non-linearity and act accordingly
(e.g., clear the measuring solution
by centrifugation or dilute the
sample).
The kinetics are
nonlinear for at
least one standard:
The coefficient of
determination is
<0.95. • Kinetic procedure with "linear
regression" measuring procedure and
evaluation procedure via standards: The
coefficient of determination for the
regression evaluation of at least one
standard measurement indicates a
significant deviation of the measuring
points from the regression line.
• Turbidity of the measuring solution.
• Measurements at the limits of the
photometric measuring range.
• Activity concentration of the enzyme too
high.
 Accept measuring result or
remeasure the standard. Before
repeating the measurement,
evaluate the reason for the
non-linearity and act accordingly
(e.g., clear the measuring solution
via centrifugation or use the
standard with low concentration).
Problem Cause Solution