Metrohm viva 1.0 Manual - Manual (Page 882)

￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭￭
870 ￭￭￭￭￭￭￭￭
viva 1.0
Evaluation
Process in which the evaluation quantities and concentrations of the indi-
vidual substances are calculated from raw data.
Intercept solution
Basic solution consisting of VMS and suppressor. It is used in the analysis
of electroplating baths for determining the intercept value with the MLAT
calibration method (see Glossary, page 870).
Intercept value
The intercept value is the charge that is obtained from the measurement
of the intercept solution. It is determined using the MLAT calibration
method (see Glossary, page 870) for the analysis of electroplating
baths.
MLAT (Modified Linear Approximation Technique)
Calibration method based on a standard addition and mainly used for the
determination of brightener in electroplating baths. First, the basic solu-
tion spiked with suppressor, referred to as the intercept solution, is mea-
sured. After the addition of sample to the intercept solution, another mea-
surement is made. This is followed by a standard addition with brightener
standard solution.
Determination of the intercept value
The intercept solution, which consists of VMS (Virgin Make-up Solution)
(see Glossary, page 873) and Suppressor, is measured first. The area of
the oxidation peak obtained from the anodic sweep is evaluated, and the
charge is calculated and saved as intercept value. This value is then sub-
tracted as a background value from the subsequent measured values.
Sample measurement
The sample, which contains suppressor and brightener, is added to the
intercept solution and measured.
Standard addition
Brightener standard solution is added once or several times to the measur-
ing solution and a measured value is recorded each time. The concentra-
tion of brightener in the sample is then calculated by means of linear
regression.
Example