Acid Digestion
Definition
A laboratory preparation step in which concentrated mineral acids are used to destroy all organic tissue in a sample, leaving only acid-resistant inorganic particles such as diatom frustules for examination. The organic residue is fully solubilised; the silica frustules are not.
- Reagent
- Concentrated mineral acids
- Target destroyed
- Organic tissue
- Residue preserved
- Acid-resistant inorganic particles, e.g. diatom frustules
- Used in
- Diatom test in drowning investigation
- Outcome
- Organic matter solubilised, silica intact
Common questions
Why does acid digestion not also destroy the diatom frustules being searched for?+
Diatom frustules are made of silica, which resists the strong mineral acids used to dissolve organic tissue, so the frustules survive digestion while surrounding flesh and blood are fully broken down.
Is acid digestion the only preparation method used for diatom recovery?+
No, enzymatic digestion and other tissue-destruction techniques are also used in different laboratories, partly to avoid the strong fumes and corrosion hazards that come with mineral acid digestion.
Related terms
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- Control Sample
- A water sample collected from the suspected drowning environment at or shortly after the time of body recovery. Its diatom assemblage is...
- Hematogenous Dissemination
- Spread of a substance via the bloodstream. In the diatom test, diatoms aspirated into the lungs during ante-mortem drowning enter pulmonary capillaries...
- Post-Mortem Immersion
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