EDTA Decalcification
Definition
Demineralisation of bone powder using 0.5 M EDTA at pH 8.0, which chelates calcium from hydroxyapatite and releases DNA from the mineral matrix. The standard approach in ISO/IEC 17025-accredited bone DNA protocols.
- Reagent
- 0.5 M EDTA
- Working pH
- 8.0
- Mechanism
- Chelates calcium from hydroxyapatite
- Standard status
- Common in ISO/IEC 17025-accredited bone DNA protocols
Common questions
Why chelate calcium before extracting DNA from bone powder?+
DNA is bound within the mineral hydroxyapatite matrix of bone, so removing calcium with EDTA releases the trapped DNA into solution, making it accessible to standard extraction chemistry that would otherwise recover very little from intact mineralised bone.
What is the trade-off of using EDTA decalcification over faster methods?+
EDTA chelation is gentle and preserves DNA integrity well but is slow, often taking days depending on sample size, so it is chosen for accredited casework where yield and quality outweigh the benefit of a faster but harsher demineralisation method.
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