What is the primary purpose of Nalgene bottles in sampling?

The primary purpose of Nalgene bottles in sampling is for reusable water sampling. These bottles are designed to provide a clean, durable, and contamination-free environment for collecting and storing water samples before they are analyzed. Their material is resistant to many chemicals, thus ensuring sample integrity over time, which is crucial in water quality testing. Additionally, their reusability allows operators to consistently collect samples without the need for single-use plastics, making them both an environmentally friendly and cost-effective choice for water sampling.

The other options do not align with the main function of Nalgene bottles in this context. While they can be used in various laboratory applications, the focus here is specifically on sampling and storage, rather than chemical reactions, volume measurements, or temperature control.