Metrohm 797 VA Computrace - Manual (Page 232)

8 How to ...?
797 VA Computrace – Software
220
3. Add Brightener standard solution several times and measure
Q(addition) for each addition. Usually, two or three standard
additions are made for the determination of Brighteners.
LAT
"LAT Standard addition for brighteners" (and "LAT Record inter-
cept value" to record the "Intercept value").
The second
Calibration technique (should only be applied if
"MLAT" is inapplicable) is "LAT Standard addition for brighte-
ners". It differs from "MLAT" in the fact that the "Intercept solu-
tion" with the "Intercept value" Q(intercept) is measured up-
front, and then removed for the actual sample measurement.
1. Determination of the "Intercept value". It can be determined
in two ways:
A. Using the
Calibration technique "LAT Record intercept
value". This Calibration technique is only used to deter-
mine the "Intercept value":
1. Place "Intercept solution" into the sample vessel .
2. Measure solution and save the result in a file.
B. Using the
Calibration technique "LAT Standard addition
for brighteners":
1. Set No. of additions and Intercept value (mC) on the
Determination tab of the EDIT WORKING METHOD
PARAMETERS window to 0. No file needs to be de-
fined for Intercept determination.
2. Place "Intercept solution" into the sample vessel and
click start. After measurement, read "Q.Mean” out of
the results sheet: That is the "Intercept value"
Q(Intercept) for this solution.
2. The determination of the Bath solution is then done using
the Calibration technique "LAT Standard addition for
brighteners":
1. Remove the "Intercept solution" from the meas-
uring vessel.
2. If you determined the "Intercept value" by
method A:
Enter path and file name of the (with "LAT Record
intercept value") recorded determination into field
Intercept determination on the Determination tab
of the EDIT WORKING METHOD PARAMETERS
window.
If you determined the "Intercept value" by method B:
Enter the determined "Intercept value" into field
Intercept value on the Determination tab of the
EDIT WORKING METHOD PARAMETERS window.