CPFT Practice Exam 2026 – Complete Test Prep Guide

A polarographic gas analyzer is specifically designed to measure the concentration of oxygen in a sample. This type of analyzer operates based on the electrochemical principle, where the reduction of oxygen at the cathode generates a current proportional to the oxygen concentration in the gas. The unique design of the polarographic sensor allows for the selective measurement of oxygen, making it a preferred choice in clinical and research settings for assessing respiratory function and monitoring oxygen levels in patients.

In contrast, carbon dioxide is typically measured using a different technology known as infrared spectroscopy or mass spectrometry, as its chemical properties do not allow it to be accurately measured using polarographic methods. Similarly, nitrogen and helium are inert gases and do not participate in electrochemical reactions that the polarographic analyzer requires for measurement, emphasizing the specificity of this method to oxygen analysis. Therefore, when considering the capabilities of a polarographic gas analyzer, oxygen stands out as the correct answer.