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Basic Operations
Linearity Test _____________________________________________________
4.4
Finnigan GasBench II
Linearity Test
The mass spectrometers normally used together with GasBench II (that is
Delta, Deltaplus, MAT 253) are not ideally linear. This means that the
measured G value depends on the actual peak height. With each IRMS, a
certain slope is guaranteed, e.g. 0.05 ‰/V for the Delta series. To check for
this effect and to ensure proper operation, the following linearity test should
be performed from time to time.
Run a sequence using the method zero.met. While the method is running, vary
the reference gas pressure to obtain different peak heights for the various
pulses. Plot peak height versus G value for 13C and 18O respectively.
Determine the slope.
Figure 4-5.
Linearity Test - Chromatogram
Figure 4-6.
Linearity Test - Result Grid
4-10 ___________________ Finnigan GasBench II Operating Manual ____________________
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