Effect of Purging a Sealed and Desiccated FTIR Spectrometer Sample Compartment Study demonstrating the inconsistency in background levels of water and carbon dioxide for an unpurged, sealed, and desiccated FTIR spectrometer as compared to a sealed and desiccated FTIR spectrometer with the sample compartment purged. aerospace climate control electromechanical filtration fluid & gas handling hydiauLlcs pneumatics process control waling & shielding Effect of Purging a Sealed and Desiccated FTIR Spectrometer Sample Compartment ENGINEERING YOUR 5UCCES5

Increase Accuracy of FTIR Analysis Effect of Purging a Sealed and Desiccated FTIR Spectrometer Sample Compartment R Daly, D Connaughton Parker Hannifin Corporation The purpose of providing a dry, CO2-free purge to an FTIRspectrometer is twofold. The purge prevents deterioration of the beamsplitter by moisture and also eliminates undesired absorbance by water and carbon dioxide in the background. Consequently, the purge enhances the instrument’s reliability by the reduction of the potential need for service and increases the accuracy of analysis by the elimination of inconsistencies in the background...

Figure 3 indicates that the carbon dioxide and water content of the air change as a result of one person being in a room of approximately 7200 ft3. In this case, the water level actually decreased, but there was a marked increase in the amount of CO2 in the air. In an actual experiment, scan sets should never be col-lected 40 min apart. This Figure simply illustrates how severe the lack of purge can be even for a sealed system. changing, and the spectrometer is a very good detector for the change. Even if the operator were to hold his or her breath while opening the sample compartment, the ambient...

Conclusion Changing levels of CO2 and water vapor in a laboratory atmosphere can result in interference from these contaminants for unpurged FTIR spectrometers. The changing levels of CO2 and water are pri-marily a result of operator breathing, and the extent of interfer-ence to the FTIR spectra is dependent on the amount of time elapsed between the background spectra and the sample spectra.Purging of the sample compartment increases the reliability and consistency of FTIR spectra. The experiments described above clearly identifed the need for purge, even for the purge-less sealed and desiccated...