Metrohm 757 VA Computrace User Manual
Page 132
5 Determination mode
757 VA Computrace – Software
122
a = Y.reg/offset Intercept of calibration curve
b = Slope
Slope of calibration curve in the
linear region
d = Nonlin. Non-linearity
factor
Calibration solutions
Y.offset
EV
0
0
Slope
c(eff)
Linear
Linear (trough Zero)
Nonlinear (trough Zero)
Nonlinear
3.
Measurement of sample solution
The sample solution with the unknown mass concentration
c(s) of the sample is measured one or more times (defined
by
No. of replications
). This gives:
EV(s)
Evaluation quantity of a single measure-
ment for the sample
mean(s)
Mean value of all evaluation quantities
for the sample
Std.dev.(s) Standard deviation of the individual value
EV(s) = s(s)
4.
Calculation of mass concentration c(s)
The sought mass concentration
c(s) of the sample is calcu-
lated by inserting mean(s) in the calibration function deter-
mined earlier:
mean(s) = d c(s)
4
+ b c(s) – a
EV
Sample
c(s)
mean(s)
c(eff)