Metrohm 746 VA Trace Analyzer User Manual
Page 560
7.7 Standard operating procedure in the context of GLP/ISO 9001 guidelines
746 VA Trace Analyzer / 747 VA Stand
7-61
7.7.4
Performing the determination
To perform the lead determination in the prepared sample solution, the following
steps are necessary:
1 Switch to dialog page ”MONITORING”
•
Press the yellow
2 Switching the program run mode to
determination
If the paramete
r Run mode
is set to
calibration
, proceed as follows
•
Use the cursor keys to select the field
Run mode
.
•
Press the
•
Press the softkey
and confirm this entry with the
key.
3 Entry of the sample volume
Enter the sample volume as follows:
•
Use the cursor keys to select the first field below the title
Sample size/S0
.
•
Press the
•
Enter
0.1 mL
and confirm this entry with the
4 Start the determination
•
Press the red
•
The sample solution is measured three times. On completion of the third
measurement, the program is interrupted. The screen shows the prompt
to add 50
µ
L of the standard addition solution
PbStd
to the measuring
vessel
ADD PbStd 50.000 uL > M
.
5 First standard addition
•
Remove stopper 25
25 and add 50
µ
L of the lead ion standard solution to
the measuring vessel through the pipetting opening using a pipette. Then
close the pipetting opening with stopper 25
25 and press the
key.
•
The spiked sample solution is measured three times. On completion of
the third measurement, the program is interrupted. The screen again
shows the prompt to add 50
µ
L of standard addition solution
PbStd
to
the measuring vessel
ADD PbStd 50.000 uL > M
.
6 Second standard addition
•
Remove stopper 25
25 and add 50
µ
L of the lead ion standard solution to
the measuring vessel through the pipetting opening using a pipette. Then
close the pipetting opening with stopper 25
25 and press the
key.
•
The sample solution spiked a second time is measured three times. On
completion of the third measurement, the results are calculated and the
reports and curves printed out (see section 4.2).