Name the requested fraction
Total, total recoverable and dissolved results can describe different prepared samples. Use the terminology required by the applicable method and program.
Plan filtration and preservation
Dissolved fractions can require a defined filtration step before preservation. Coordinate the procedure and equipment through the project instructions rather than filtering after the fact without a plan.
Keep paired samples identifiable
Where more than one fraction is needed, maintain separate bottle and sample identifiers. Both field and laboratory records should show which result belongs to which preparation.
Compare the correct basis
Do not treat results from different fractions as interchangeable. Interpret differences with solids, sampling and preparation context.
Related testing & guidance
Technical & service references
Vanguard water-testing menuEPA: Clean Water Act method questionsEPA: Drinking-water analytical methodsSource review: November 8, 2026. The agreed method and project scope govern the testing.