Metrohm 797 VA Computrace User Manual

Page 233

8.6 Analyze Electroplating Bath Solutions

797 VA Computrace – Software

221

3. Define the

No. of additions

on the

Determination

tab of the

EDIT WORKING METHOD PARAME-

TERS

window.

4. Place the "Bath solution"

into the sample vesse-

and click start. Q(Bath) is determined.

5. Add Brightener standard solution several times

and measure Q(addition) for each addition. Nor-
mally, two or three standard additions should be
done for the brightener determination.

Note: If you make several measurements of bath solutions
with the same composition, you can do the actual determi-
nation of the "Bath solution" several times with the same
"Intercept value". However, the "ntercept value" sould be
redetermined in regular intervals.

For Suppressor analyses:

Dilution Titration Technique
"DT Suppressors with calibration curve", and "DT Record calibra-
tion curve" to record the calibration curve.
The "Dilution

Titration

Technique" is used for the determination

of Suppressors. It consists of two measurement parts:

A. “DT Record calibration curve”

This

Calibration

technique is used to record the calibration

curve and determine the “Calibration factor” with addition
of a standard solution containing a known Suppressor con-
centration.

Typical

standard addition scheme for DT Record calibration

curve:

1. Define "Addition ratio" and "Evaluation ratio" on the

Substances

tab of the

EDIT WORKING METHOD PA-

RAMETERS

window.

2. Place the VMS (Virgin Make-up Solution) into the

sample vessel and click on start. Q(0) is determined.

3. Add Suppressor standard solution and measure

Q(addition) for each addition, until Q/Q(0) < "Additi-
on ratio". If the "Addition ratio" is reached with less
than 5 or more than 20 additions, the concentration
of the Suppressor standard solution or the addition
volume should be adjusted.

B. "DT Suppressors with calibration curve"

This

Calibration

technique is used to determine the Suppres-

sor concentration. The scheme is similar to "DT Record cali-
bration curve", except that not standard solution, but Pro-
duction bath solution is added to the VMS.