6
Using EA IsoLink IRMS System for CNSOH
Performing a Jump Calibration
Thermo Scientific
EA IsoLink IRMS System for CNSOH Operating Manual
85
Due to the separation of the gas chromatographic column the acquisition is divided in two parts, each
dedicated to the isotopic species (i.e. gas configuration).
As soon as the first species has been identified (i.e.
H
2
or
N
2
), Isodat Software Suite automatically
changes the magnetic field so that the mass traces of the second isotopic species (i.e.
CO
or
CO
2
) can
be recorded (see:
Switch Gas
column in the
Time Events
list).
If no hydrogen or nitrogen peak can be found, Isodat waits a defined time, for example 25 s, before
switching to the second gas configuration.
Figure 86.
Dual Measurement for NC - Schematic Chromatogram
Performing a Jump Calibration
In order to determine the isotope ratios of different elements during the same run, switching to
another Gas Configuration is necessary. In contrast to a single element measurement, in which the
magnetic field runs the gamut from high to low and after that to the pre-calculated magnetic field,
there is not sufficient time in dual measurement to perform this procedure for the next gas
configuration. For this reason, a so-called
Jump Calibration
from the first gas configuration to the
next gas configuration is necessary. After the
Jump Calibration
has been performed, the computer
finds exactly the peak center even without performing any peak center procedure. A Jump Calibration
should be performed daily to stabilize the performance of the magnet jump.
How to perform a jump calibration
The following procedure describes how to perform a jump calibration for
H
2
--> CO
.
For an
N
2
--> CO
2
jump calibration proceed similarly.
1. Open
Instrument Control
.
2. Choose your
Configuration
containing ConFlo IV and EA IsoLink IRMS System for CNSOH.
3. Allow
CO
reference gas to enter the source. In case of an
N
2
--> CO
2
jump calibration open CO
2
reference gas.
4. Select
Scan | Jump Calibration
.
