What is the function of sodium thiosulfate crystals in prepared water sample bottles?

Sodium thiosulfate crystals are specifically used in prepared water sample bottles to neutralize the chlorine that may be present in the water sample. Chlorine is commonly used as a disinfectant in water treatment processes, but it can interfere with the analysis of certain water quality parameters when testing a sample. By adding sodium thiosulfate, any free chlorine is effectively inactivated, allowing for an accurate assessment of other components in the sample without the interference of chlorine’s oxidizing effects. This is crucial for obtaining reliable data when analyzing water quality, particularly for parameters that are sensitive to chlorine.

While the other functions mentioned may seem plausible, they do not accurately represent the primary role of sodium thiosulfate in this context. Enhancing chlorine levels or preserving taste are not associated with the use of sodium thiosulfate. Preventing bacterial growth, while important for sample integrity, is not the primary function since the intent here is to neutralize chlorine rather than inhibit microbial activity.