Metrohm 746 VA Trace Analyzer User Manual
Page 150
4.6 Basic method for DPASV
746 VA Trace Analyzer / 747 VA Stand
4-65
4
Start the determination
•
Press the red
•
The status display in the header of the dialog page "MONITORING"
switches to
* BUSY *
, the start time of the measurement is entered un-
der
Determination
and the determination is given a standard name,
also formed from the start time. Further, during the measurement the
measurement window is superimposed which shows the current pro-
gram line being executed and the remaining line time.
•
Shortly after the start of the determination, the screen shows the prompt
to add 10 mL sample to the measuring vessel.
5
Addition of sample
•
Remove stopper 25
25 on 747 VA Stand and use a pipette to add 10 mL of
drinking water to the measuring vessel through the pipetting opening.
Press the
•
The screen shows the prompt to add 1 mL acetate buffer to the measur-
ing vessel.
6
Addition of acetate buffer
•
Use a pipette to add 1 mL acetate buffer (1 mol/L, pH 4.6) to the
measuring vessel through the pipetting opening. Then close the pipet-
ting opening using stopper 25
25 and press the
7
Measurement of the sample solution
•
Measurement of the sample solution runs as follows (see also section
4.5.3):
−
Purging and stirring for 330 s.
−
Call-up of the segment
ASV
for measured value recording. The
substances present in the sample solution are enriched at the
hanging mercury drop with stirring at a measurement voltage of
–1150 mV and then determined anodically without stirring from
–1150 ... 150 mV. The single measurement is allocated the VR
number
00
.
•
On completion of the measurement, the program is at an end. The status
display in the header of the dialog page "MONITORING" switches back
to
* READY *
, the instrument is ready for a new determination.
8
Printout of the segment curve
•
On completion of the program, the smoothed segment curve entered on
the "DOCUMENTATION" page is put out on the printer. The following ex-
ample shows a determination with drinking water as sample: