Midi Spin Column Plasmid Kit (PA025)

The Midiprep Spin Column Plasmid Kit was designed for plasmid and cosmid DNA purification from 50-100 ml of cultured bacterial cells using a plasmid midiprep spin column system. This plasmid kit uses a modified alkaline lysis method and RNase treatment to obtain clear cell lysate with minimal genomic DNA/RNA contaminants. In the presence of chaotropic salt, plasmid DNA in the lysate binds to the glass fiber matrix of the plasmid spin column. Contaminants are removed with a Wash Buffer (containing ethanol) and the purified plasmid DNA is eluted by a low salt Elution Buffer, TE or water. Typical yields are 200-350 μg for high-copy number plasmid or 30-100 μg for low-copy number plasmid from 50 ml of cultured bacterial cells. DNA phenol extraction or alcohol precipitation is not required and the entire procedure can be completed within 35 minutes.

Quick Protocol




Advantages (Cat. # PA025)

  • Purify plasmid DNA from large volume samples within 35 minutes!
  • Midi spin column format
  • High Yield: up to 400 μg of plasmid DNA
  • Large Sample Volume: 50-100 ml of cultured bacterial cells
  • Glass fiber membrane optimized for plasmid DNA purification from large volume bacteria samples
  • Elution Volume: 1 ml
  • Storage: dry at room temperature (15-25ºC)


Restriction Enzyme Digestion, Library Screening, Ligation, PCR, Transformation and Sequencing Reactions


  • PD1, PD2, PD3 Buffers
  • W1 Buffer
  • Wash Buffer
  • Elution Buffer (10 mM Tris-HCl, pH8.5 at 25°C)
  • RNase A
  • PA Columns

Quality Control

The quality of the Midiprep Spin Column Plasmid Kit is tested on a lot-to-lot basis according to Geneaid's ISO-certified quality management system. Plasmid DNA from a 50 ml overnight E. coli (DH5α) culture, containing plasmid pBluescript (A600 > 2 U/ml) is purified using the High-Speed Plasmid Advance Kit. Following the purification process, a yield of more than 200 μg is obtained and the A260/A280 ratio is between 1.8-2.0. The purified plasmid (1 µg) is used in EcoRI digestion, and checked by electrophoresis.

Midiprep Spin Column Plasmid Kit Functional Test Data
Figure 1. Plasmid DNA was extracted using the Midiprep Spin Column Plasmid Kit. 5 μl aliquots of purified supercoiled plasmid DNA [100 ml overnight E. coli (DH5α) culture, containing a 3 kb plasmid pBluescript] from a 1 ml eluate were analyzed by electrophoresis on a 1% agarose gel.
M = Geneaid™ 1 Kb DNA Ladder
Lane 1-2: pBluescript
1383.51.941.94383.5 µg
2384.81.921.94384.8 µg
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