Three strategies: (a) laboratory mixing and static spectral acquisition, (b) IBC mixing and static spectral acquisition and (c) IBC mixing and dynamic spectral acquisition were investigated for obtaining the most relevant and representative calibration samples.
For IBC mixed blends, the spectral acquisition was carried out in-line for 2 min and stopped for static spectral acquisition.
Calibration models using dynamic spectral acquisition were prepared and validated using design of experiment approach.
Spectral acquisition and the calculations were performed in the same manner as described in "Calibration procedures".
MK acknowledges the help of Janek P. Dann with spectral acquisition.
Spectral acquisition and spectral analysis were carried out by the Labspec6.0 software.
The test chamber pressure was maintained below 10−9 mbar during spectral acquisition.
Pressure in the analytical chamber during spectral acquisition was less than 5 × 10-9 Torr.
High temperature micro-ATR IR spectroscopy has recently become available, allowing for convenient IR spectral acquisition at elevated temperatures.
Models built using IBC mixed blends and dynamic spectral acquisition resulted in the most accurate predictions for all the blend components, whereas models prepared using static spectral acquisition (laboratory mixed and IBC) showed erroneous prediction results.
Also presented is a novel optical design in order to achieve multiple, independent and simultaneous spectral acquisition, including auto-calibration.
