Owner manual

4.6 Basic method for DPASV
746 VA Trace Analyzer / 747 VA Stand
4-65
4
Start the determination
• Press the red <START> key.
• 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 2525 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 <ENTER> key.
• 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 2525 and press the <ENTER> key.
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: