What methods are commonly used to preserve samples collected for testing?

The correct choice includes methods such as using acids, bases, and refrigeration, which are essential for preserving samples collected for testing.

The use of acids and bases can help stabilize certain compounds in the sample, particularly in cases where the pH of the sample may cause degradation or conversion of analytes. This is crucial in environmental testing where samples may be susceptible to changes in chemical composition due to natural chemical reactions over time.

Refrigeration is a widely accepted technique to slow down biological activity and reduce the metabolic processes of microorganisms, which helps in preserving the integrity of the sample. Lower temperatures help to prevent the decomposition of organic materials and minimize the risk of altering the composition of the samples for accurate analysis later.

In contrast, other listed methods may not be suitable or effective for sample preservation. Heating or boiling can lead to degradation or the alteration of certain compounds within the sample. Filtering might be used for sample preparation, but it does not preserve the sample itself. Cooling and dilution are useful in specific contexts, but rely heavily on appropriate conditions that don’t modify the sample components significantly. Oxidation and evaporation generally result in the loss of volatiles and can change the dynamics of the sample composition, making them less applicable for preservation.