Buchi DuMaster D-480, Руководство по эксплуатации

Страница: 178 / 354

Operating instructions DuMaster D-480 ©BÜCHI Labortechnik AG
8 - Maintaining the instrument 178

Click
OK
to save your settings and close the dialog.

If you have decided to split the calibration into a lower and an upper range the "Specify lower and
upper calibration range" dialog appears. Set the dividing line by clicking the
<
and
>
buttons and
then click
OK
.

First, the calibration curve for the lower range appears in the calibration view.
Phase 4: Optimizing calibration curves and apply calibration
Background information can be found in
Assessing the calibration curves
(on page 179).
In order to optimize the calibration curve for each element you must exclude samples that deviate
significantly from the curve. Deviations of up to ± 1.3 µg are tolerable.
Proceed as follows:

Zoom in/out the graph by selecting
View > Zoom in/out
so that you can check the overall curve.

Click the and buttons to move from sample to sample in the calibration curve and
check the deviation "Diff.". Samples that display excessive deviation must be deleted.

Select a sample to delete. Then click the "Include/Exclude" button" . The deleted sample is
highlighted red.

Compare "r" (new value) and "r_old" (old value) of the calibration curve and check whether
deleting has had the desired effect. See
Assessing the calibration curves
(on page 179).

If deleting has not had the desired effect, you can undo it. To do so, select the deleted sample
and click the "Include/Exclude" button again. The sample is now included again.

Once you have excluded all samples with significant deviations from the calibration curve, click
the "Next" button. The next calibration curve appears in the calibration view.

Once you have optimized the last calibration curve and clicked the "Next" button, the
"Calibration coefficients" dialog is displayed.

Check...

... the calibration coefficients "a" to "e".
Note:
For the lower calibration range it is important that coefficient "a" is 1x10 -3 ... 3x10 -2 or less.
Coefficient "a" corresponds to a calibrated blank value and should be as small as possible.

... the possible working range defined in "Min." and "Max.".

Decide:
If...

... you accept the calibration coefficients: Click
OK
. The calibration coefficients are applied.

... you do not accept the calibration coefficients: Click
Cancel
. Calibration is aborted.