Elementar Analysensysteme GmbH vario EL cube Operating Instructions Manual page 162

10 - CHN determination with the liquid autosampler vario LS
Prior to a calibration series, the filling of the combustion and reduction tube have to be renewed and
the instruments has to be checked for leaks.
Recommended calibration
For CHN the following is recommended:

Mixture of Hexadecane an Pyridine.

Hexadecane:
d = 0.773 mg/µl; 84.87 % C; 15.13 % H

Pyridine:
d = 0.978 mg/µl; 17.71 / N; 75.92 % C; 6.37 % H

For a calibration range of 0.14 mg N abs., max. 6.6 mg C abs., max. 1.1 mg H abs. fill exactly the
following amounts into a 100 ml volumetric flask:

92.0 ml Hexadecane

8.0 ml Pyridine
The data for the standard solution are as follows:
d = 0.7894 mg/µl; 83.98 % C; 14.26 % H; 1.754 % N.
These data have to be saved under Options > Settings > Standards.
By weighing-in the different substances in a 100 ml volumetric flak a better accuracy of the
percentage can be reached. (Temperature dependency of the density etc.).
Numerical example
In the following a numerical example is given which should clarify the data of the standard solution
mentioned above.
Calculation of the weights from the individual volumes:
Volumetric flask (empty):
+ 92 ml Hexadecane:
+ 8 ml Pyridine:
 = 100 ml mixture
Calculation of absolute element contents:
71.116 g Hexadecane
7.824 g Pyridine
78.940 g mixture
Calculating the percentages of the test substance (mixture):
% C = 66.296 g C · 100
% H = 11.258 g H · 100
% N = 1.385 g N · 100
Calculating the density of the test substance:
Density =
Variants Operating Instructions vario EL cube
79.945 g
151.061 g
158.885 g
= 60.356 g C + 10.760 g H
= 5.940 g C
66.296 g C
= 83,982 %
78.940 g
= 14,261 %
78.940 g
= 1,754 %
78.940 g

= 100 %
78.940 g = 0.7894 g/ml
= net: 71.116 g
= net: 7.824 g

78.940 g
+ 0.498 g H + 1.385 g N
11.258 g H 1.385 g N
©Elementar Analysensysteme GmbH
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