How should samples that cannot be analyzed immediately be maintained until the analysis is conducted?

Samples that cannot be analyzed immediately should be preserved to maintain their integrity and prevent any chemical or biological changes that could alter the results of the analysis. Preservation techniques may involve adding chemical agents that stabilize the sample or keeping it under specific environmental conditions (such as refrigerating or freezing) depending on the type of sample and the analysis required.

Proper preservation is crucial for accurate testing outcomes, especially for water samples that may contain microorganisms, nutrients, or contaminants that can degrade over time or react with substances in the environment. Without effective preservation, the samples might not yield reliable results when finally analyzed, which could lead to incorrect conclusions regarding water quality or safety.

In this context, while freezing, room temperature storage, or dilution might seem like options, they do not effectively ensure that the sample will remain stable and unchanged until analysis. Preservation, however, encompasses the necessary steps to stabilize sample composition and ensure the results are reflective of the actual conditions at the time of sampling.