Why are septum vials utilized for Total Toxic Organics (TTO) samples?

Septum vials are utilized for Total Toxic Organics (TTO) samples primarily to prevent sample contact with air. This is critical because exposure of the sample to air can lead to various changes in the chemical composition, including oxidation or evaporation of volatile compounds. By minimizing contact with air, septum vials help preserve the integrity of the sample, ensuring that the analysis reflects the true composition of the original sample collected.

The design of septum vials includes a sealed closure with a rubber or silicone septum, which creates an airtight seal when properly closed. This feature is essential in TTO sampling, as it protects the sample from environmental factors that could alter its chemical makeup, which is especially important for accurately assessing the presence of toxic organics.

In contrast, while factors such as maintaining temperature, preventing contamination from light, or enhancing chemical stability are important in various contexts for sample storage and analysis, they do not specifically address the primary function of preventing air exposure. Thus, ensuring an air-tight sample environment is the main reason for the use of septum vials in TTO sampling.