Instruction Manual

8.7 Standard addition technique
797 VA Computrace – Software
247
8. Select the Determination tab (see section 5.2) and enter Sample
identifier
, Sample amount, Cell volume, and the number of
spiked solutions in the No. of cells field.
9. Select the Substances tab (see section 5.2) and make sure that
for each substance entered in the table the concentrations of
the spiked sample solutions are defined in the CELL CONCEN-
TRATIONS
window which is opened by clicking on the
button.
10. Close the EDIT WORKING METHOD PARAMETERS window by
clicking <OK>.
11. Place the sample solution in the measuring vessel at the 797
VA Computrace stand.
12. Click on or MAIN WINDOW / Window / Monitor to open
the MONITOR window.
13. Start the measurement by clicking the icon in the MAIN
WINDOW
or the button in the MONITORING win-
dow.
14. Enter the Sample ID (used as part of the determination file na-
me) in the PLACE SAMPLE window and click <OK>.
15. Each time a solution exchange is required in the BATCH SOLU-
TION EXCHANGE
window, replace the measuring solution by
the next spiked sample solution.
Use automatic standard addition
In the automatic standard addition, a known amount of the analyte
is added once or several times to the sample using 700/800 Dosi-
nos, or 685/805 Dosimats. Proceed as follows:
1. Install Dosing Devices to the 797 VA Computrace stand (see
How to Install Dosing Devices for automatic addition, section
8.1).
2. Click on or MAIN WINDOW / Mode / Determination.
3. Click on or MAIN WINDOW / Window / Working method
specification
to open the WORKING METHOD SPECIFICATIONS
window.
4. Load the desired method into the WORKING METHOD SPECIFI-
CATIONS
window (see How to Load a method, section 8.4).
5. Select
Standard addition in the Calibration field of the WORK-
ING METHOD SPECIFICATIONS
window.
6. Select Automatic for Addition in the WORKING METHOD SPECI-
FICATIONS
window.
7. Click to open the DOSINOS window.