Linear Regression: Spectrophotometric determination of Mn
For users of the Mathcad browser:
wmc-rl1.mcd (7 KB, ver. 5.0)In the
spectrophotometric determination of manganese (as permanganate) a linear
dependence of the absorbance for a given concentration range is
obtanied:
| c/(mmol/L) | 0.186 | 0.459 | 0.728 | 0.906 | 1.094 | 1.351 | 1.647 | 1.838 |
| A | 0.092 | 0.202 |
0.321 | 0.401 |
0.498 | 0.602 | 0.731 | 0.820 |
The formula for this linear
dependence can be written as y=b*x+a, where y
corresponds to the absorbance and x to the concentration
(or A=b*c+a). The parameters b and
a, are the slope of the line and the intercept with the
ordinate, respectively.
In MathCAD, the data series are defined as
vectors (one-column matrices). The syntax for the slope and the
intercept, as well as the correlation of the two sets of data is simple,
as illustrated in the following example: 
The unknown concentrations of samples can be determined from
« Home » « Mathcad Menu »
