Appendix E FTIR Frequency scale calibrationCalibration Transfer between FTLA2000 and MB3000 systems
AA003700-01 rev. G. 2.0
71
The mean frequency for broad spectra is 7299.79 cm
-1
while for narrow spectral
features it will appear higher.
When verifying the frequency calibration with the narrow water vapor line at 1 cm-
1 resolution, for the same broad spectra average frequency, the water vapor
frequency will be at different apparent locations. It means that to transfer
calibrations from the FTLA to the MB3600, slightly different values for the water
vapor frequency calibration are required. The difference in frequency can be
determined by means of the reproducibility test with Toluene which will require
different water vapor frequency assignments to provide the best match.
Similarly for the vial sampling accessory, the effective illumination distribution is
not the same between the FTLA and the MB3600. For the FTLA, the limiting slit of
the vial accessory is perpendicular to the long axis of the source filament and hence
the combination forms a small square illumination spot as shown in figure 7
Figure E- 7. Illumination distribution for FTLA with vial sampling accessory
