Conductometric determination of CO2 in air samples

Area of Science:

• Environmental Science
• Analytical Chemistry
• Atmospheric Chemistry

Background:

• Accurate determination of atmospheric carbon dioxide (CO2) concentrations is crucial for climate monitoring and environmental research.
• Existing methods for CO2 analysis can be complex or lack automation, posing challenges for routine measurements.

Purpose of the Study:

• To develop and validate a new, automated procedure for quantifying CO2 concentrations in various air samples.
• To achieve high precision and accuracy in CO2 determination suitable for environmental and physiological monitoring.

Main Methods:

• Air samples are analyzed by absorbing carbon dioxide (CO2) into a strontium hydroxide (Sr(OH)2) solution.
• The decrease in electrical conductivity of the Sr(OH)2 solution, resulting from CO2 absorption, is measured.
• A direct current (d.c.) strip-chart recorder automatically registers the conductivity changes, with the curve's decline proportional to absorbed CO2.

Main Results:

• The procedure allows for the determination of CO2 quantities up to approximately 8 micromoles (µmol) with an error of less than 0.02 µmol.
• Accurate analysis of 2 to 8 µmol of CO2 is achievable in samples as small as 150 ml of fresh atmospheric air.
• The method provides an accuracy of better than +/- 1.0% for CO2 content in samples of atmospheric air, carboxygen, or expired air.

Conclusions:

• The developed procedure offers a reliable and automated method for precise CO2 concentration measurement in air.
• This technique is suitable for analyzing CO2 in diverse samples, including atmospheric air and respiratory gases.
• The high accuracy and sensitivity of this method contribute to improved environmental monitoring and physiological studies.