Solid-Phase Extraction
Definition
A family of methods in which DNA binds selectively to a silica membrane or magnetic bead under high-salt, low-pH conditions, is washed to remove inhibitors and proteins, and is then eluted in a low-salt buffer or water. The basis of most commercial forensic DNA extraction kits and compatible with automation platforms.
- Binding phase
- Silica membrane or magnetic bead
- Binding condition
- High-salt, low-pH buffer
- Elution condition
- Low-salt buffer or water
- Use
- Basis of most commercial forensic DNA extraction kits
- Compatibility
- Suited to automated liquid-handling platforms
Common questions
How does this differ from organic (phenol-chloroform) DNA extraction?+
Solid-phase methods bind DNA reversibly to a silica or magnetic surface and remove contaminants by washing, avoiding hazardous organic solvents and enabling closed-tube or automated processing, whereas phenol-chloroform extraction separates DNA by differential solubility across an organic and aqueous phase and requires manual phase separation.
Why is compatibility with automation significant for casework labs?+
High-throughput DNA units process large batches of reference and evidence samples, and a solid-phase chemistry that works on magnetic beads can be run on robotic platforms, which improves consistency and reduces contamination risk compared with manual extraction of each sample.
Related terms
- Chelex Extraction
- A rapid extraction method that uses the chelating resin Chelex 100 to bind divalent metal ions and prevent nuclease activity. Cells are...
- Differential Extraction
- A two-step DNA extraction procedure used when a stain contains both sperm cells and non-sperm epithelial cells. The first step lyses epithelial...
- Organic Extraction
- A DNA isolation method that uses phenol and chloroform to partition proteins into the organic phase, leaving nucleic acids in the aqueous...
- PCR Inhibitor
- A co-extracted substance that interferes with Taq polymerase activity or primer annealing. Common inhibitors in forensic samples include haemoglobin (from blood on...
- Real-Time PCR Quantification
- A method that measures the concentration of human-specific amplifiable DNA in a forensic extract by monitoring fluorescent signal accumulation during PCR in...