Metrohm viva 1.1 (ProLab) - Manual (Page 1063)

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Glossary
viva 1.1 (for process analysis)
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areas are standardized in order to improve the comparability of the mea-
suring results obtained. This is achieved by setting up the quotient Q/Q(0)
of the currently measured signal Q and the start value Q(0) and plotting it
against the effective addition volume VEFF for each step (see Glossary,
page 1052). The addition of standard solution is repeated until the Eval-
uation ratio defined in the method (usually Q/Q(0) = 0.5) has been
achieved. The recorded calibration curve is then used to calculate the Cal-
ibration factor, which expresses the suppressor concentration in the
measuring vessel for the Evaluation ratio (see Chapter 5.6.7.7.11, page
720).
Sample measurement
The suppressor concentration in the sample is determined under the same
conditions used for the calibration, with the difference that sample solu-
tion and not the suppressor standard solution is added to the basic solu-
tion. Once the Evaluation ratio has been achieved, the suppressor con-
centration in the sample is calculated from the determined effective addi-
tion volume with the help of the previously determined calibration fac-
tor (see Chapter 5.6.7.7.20, page 723).
Example
The example shows the calibration curve for the standard (gray) and the
measurement curve for the sample (blue) with the values determined for
the effective addition volume VEFF(STD) = 74.8 µL and VEFF(SMPL) =
147.44 µL for the evaluation ratio Q/Q(0) = 0.5.
Dilution volume
If a sample is diluted, then the dilution volume refers to the entire volume
of sample and dilution solution. Of this diluted sample, the analysis vol-
ume (see Glossary, page 1046) is then added to the measuring vessel (see
Glossary, page 1057).