Which class of compounds is particularly prone to degradation or adsorption if not cooled during storage?

• A. VOCs
• B. NOx
• C. Ozone
• D. CO2

Answer: (A)

Preserving volatile analytes during storage is key. Compounds with high volatility tend to slip out of containers or stick to the walls, and they can react or degrade more quickly when stored warm. Cooling slows these processes: lower temperatures reduce the rate at which they evaporate, cut down on adsorption losses to container surfaces, and slow chemical reactions that could change or break them down. Because of these sensitivity to storage temperature, volatile organic compounds are especially prone to degradation or adsorption if not kept cooled.

The other gases are generally less affected by storage temperature in typical sealed, properly inert containers. They don’t volatilize or adsorb to the same extent on common collection materials, and CO2 is relatively stable under usual storage conditions.