Owner manual

7.7 Standard operating procedure in the context of GLP/ISO 9001 guidelines

746 VA Trace Analyzer / 747 VA Stand

7-59

Testing the stirrer

• Press the softkey <Stirrer> several times and check the on/off switch-

ing of the stirrer motor.

Copying the TEST747.mth method to the working storage

• Press the yellow <METHODS> key.

• Use the cursor keys to select the TEST747.mth method.

• Press the softkey <Copy to> and then <Working storage>.

Entry of the sample volume

• Press the yellow <MONITORING> key.

• Use the cursor keys to select the parameter Sample size/S0.

• Press the <CLEAR> key.

• Enter <*> and press <ENTER>.

Start program

• Press the <START> key.

• Attach the electrode cable as described in the instructions on the screen

to the clamping screws of the dummy cell.

Assessment of the linearity

• The first of the printed curves should satisfy the following conditions:

− In principle, the plotted diagonal must be straight. Small deviations

are partly due to the resolution of the printer.

− Current at voltage – 200 mV: – 1.6 µA ... – 2.4 µA*

− Current at voltage +200 mV: +1.6 µA ... +2.4 µA*

* These tolerance values refer to illustrative scatters, that is to the differences

between individual instruments. The value determined for a specific instrument

shows less scatter. The deviation depends mainly on the temperature and should

be around 10%.

Assessment of peak measurement

• The second curve plot should satisfy the following conditions:

− A symmetrical, gaussian-shaped peak should be plotted. The

evaluation must provide a result for the peak voltage U

and the peak

current I, which are printed out at the end of the curve.

− Peak voltage U : – 450 mV ... – 550 mV