Certified Pulmonary Function Technologist (CPFT) Practice Exam

Which gases are analyzed using an infrared absorption analyzer?

1. Oxygen and Nitrogen

2. Carbon Dioxide and Carbon Monoxide

3. Helium and Argon

4. Hydrogen and Methane

The correct answer is: Carbon Dioxide and Carbon Monoxide

An infrared absorption analyzer is specifically designed to detect gases that absorb infrared radiation. The gases most commonly analyzed by this method include carbon dioxide and carbon monoxide. This is due to their molecular structure, which allows them to absorb infrared light at specific wavelengths. In the case of carbon dioxide, it has vibrational modes that can absorb infrared radiation, making it a significant gas for analysis in applications such as environmental monitoring and respiratory assessments. Similarly, carbon monoxide has strong infrared absorption characteristics that allow for effective measurement using this type of analyzer. Other gases listed do not have the same infrared absorption properties. For example, oxygen and nitrogen do not absorb infrared radiation in the same way, as their molecular structures lack the necessary vibrational modes. Helium and argon are noble gases that are generally inert and do not participate in infrared absorption. Hydrogen and methane can absorb infrared radiation, but methane is far more commonly analyzed for its environmental and metabolic significance with infrared analyzers than hydrogen due to its high relevance in studies of climate change and combustion processes. Thus, carbon dioxide and carbon monoxide stand out as the primary gases analyzed by infrared absorption analyzers due to their unique properties that allow them to interact with infrared light.