Metrohm 757 VA Computrace - Manual (Page 169)

7.9 Diagnostic procedures
757 VA Computrace – Software
159
Perform a GLP test
The requirements of GLP (Good Laboratory Practice) include the
periodic testing of analytical instruments with regard to repro-
ducibility and accuracy using
standard operating procedures.
Metrohm suggests the procedure described below as the stan-
dard operating procedure for testing the 757 VA Computrace
Stand:
1. Click on or MAIN WINDOW / Mode / Determination .
2. Click on or MAIN WINDOW / Window / Working method
specification
to open the
WORKING METHOD SPECIFICATIONS
window.
3. Perform the linearity test with the dummy cell (see How to per-
form a linearity test).
4. Perform the peak test with the dummy cell (see How to per-
form a peak test).
5. Click on or MAIN WINDOW / File / Load method .
6. Select the method file
Test Pb in standard solution.mth
in the
OPEN window and click <OK> . The method is loaded into the
WORKING METHOD SPECIFICATIONS window.
7. Add 20 mL ultrapure water to the empty measuring vessel at
the 757 VA Computrace Stand.
8. Add 0.5 mL potassium chloride c(KCl) = 3 mol/L (Metrohm
No. 6.2308.020) to the measuring vessel.
9. Click on or MAIN WINDOW / Window / Monitor to open the
MONITOR window.
10. Start the measurement by clicking the icon in the MAIN
WINDOW or the button in the MONITORING window.
The PLACE SAMPLE window appears.
11. Add 100 µL Pb ion standard solution ρ (Pb) = 1 g/L (Metrohm
No. 6.2301.100) into the measuring vessel and click the <OK>
button.
12. The sample solution is measured three times. Then the MAN-
UAL ADDITION window appears.
13. Use a pipette to add 100 µL Pb ion standard solution ρ (Pb) =
1 g/L (Metrohm No. 6.2301.100) into the measuring vessel
and click the
<OK> button.
14. The sample solution spiked with standard addition solution is
measured three times. Then the MANUAL ADDITION window
appears.