What is the correct procedure to prepare for a total metals test after rinsing with tap water?

The procedure to prepare for a total metals test after rinsing with tap water involves using nitric acid for cleaning because it effectively removes organic contaminants and metal ions that may be present, thus preventing cross-contamination of samples. Nitric acid is particularly suited for this purpose because it can dissolve many metal oxides and hydroxides, ensuring that the glassware or containers being used for the samples are free from potential interferences.

In the context of preparing for a total metals test, using nitric acid helps achieve a higher level of cleanliness necessary for trace metal analysis. This is crucial in analytical chemistry because even minute residues can significantly affect the test results, leading to inaccurate assessments of the metal concentrations in wastewater samples.

While other acids like hydrochloric acid or sulfuric acid can also clean laboratory equipment, they may not be as effective in removing certain metal contaminants that are relevant for total metals tests. Additionally, if distilled water is used after rinsing with tap water, it may not adequately mitigate any remaining contaminants, as it alone does not have the refining capabilities of nitric acid. Hence, using nitric acid provides the most effective cleaning protocol for ensuring reliable and accurate results in total metals testing.