No DNA Recovered from Plasmid Miniprep

Symptom

No detectable plasmid DNA is recovered after miniprep purification. Column elution yields no nucleic acid by spectrophotometry or gel electrophoresis.

1. 1 Buffers added in incorrect order disrupting bind-wash-elute sequence
2. 2 Ethanol not added to Plasmid Wash Buffer 2 before use
3. 3 Plasmid loss during culture growth due to inadequate antibiotic selection
4. 4 Bacterial culture lost selective pressure allowing plasmid-free cells to dominate

1. 1 Add buffers in correct sequence: resuspension → lysis → neutralization → wash → elution
2. 2 Verify ethanol was added to Plasmid Wash Buffer 2 per kit instructions before first use
3. 3 Use proper antibiotic at correct concentration to maintain selection (check plasmid resistance marker)
4. 4 Confirm antibiotic stock solution is fresh and stored correctly (-20°C for most antibiotics)

Related Video (3)

QIAGEN ★ 92

Protocol: Plasmid DNA Purification using the QIAprep Spin Miniprep Kit and a Vacuum Manifold

"Demonstrates the exact bind-wash-wash-elute spin miniprep protocol whose buffer order the failure describes."

Bilibili (China-Accessible Mirrors) ★ 85

Plasmid DNA Extraction Miniprep Protocol

"Hands-on plasmid miniprep walkthrough showing correct stepwise buffer usage, directly illustrating the failure technique."

Promega Corporation ★ 72

How to Perform Plasmid Prep

"Plain-language overview of plasmid prep steps useful for understanding where incorrect buffer order derails recovery."