What is the primary use of a gas chromatograph?

The primary use of a gas chromatograph is to analyze gaseous mixtures and their concentration. This analytical technique separates chemical compounds in a gaseous sample based on their volatility and interaction with a stationary phase within the chromatograph. By passing a mixture through a column filled with a stationary phase, different components are separated over time and can be detected and quantified. This capability is essential in various fields, including environmental monitoring, quality control in the chemical industry, and forensic science, where accurately identifying the composition of gases is crucial.

While other options mention important processes in chemistry and safety, they do not align with the primary function of gas chromatography. For instance, measuring temperature in chemical reactions, determining pH levels, or assessing risk levels can involve other specialized instruments and methodologies, but they do not capture the specific analytical application of gas chromatographs, which focuses on gaseous mixtures.