What is the preservation time and chemical used for a metal analysis?

For metal analysis, the preservation of samples is crucial to obtaining accurate results. When using nitric acid as a preservative, it serves to stabilize the metals in the sample while preventing contamination and changes in concentration during storage.

Nitric acid effectively reduces the risk of precipitation of metal hydroxides, which can occur if the sample is left untreated or preserved improperly. It also helps maintain metals in their ionic form, making them more readily quantifiable in subsequent analyses.

The specified preservation time of 6 months with nitric acid is standardized for many metal analyses, ensuring that the sample remains stable and representative of its original state when analysis occurs. This makes nitric acid the ideal choice among typical preservation methods utilized in water quality testing and metal analysis.

In contrast, while other chemicals and preservation times may exist, they either don't stabilize metals as effectively, have shorter preservation times, or are less commonly used in this context. The critical factor here is that nitric acid reliably maintains the integrity of the metal ions over an extended period, which is essential for accurate analytical results.