CosMCPrep Performance and Data

High and Low Copy Plasmid Purification

CosMCPrep is a versatile plasmid purification procedure based on the Solid Phase Reversible Immobilization (SPRI) paramagnetic bead-based technology. CosMCPrep uses a single protocol to purify a variety of high and low copy number templates while maintaining the flexibility to support both manual and automated processing.

  • Isolation of high quality plasmids
  • Single protocol for the purification of all template types
  • Automation procedures produce minimal variability in plasmid yield and quality 


High Recovery of High Quality Small Plasmid DNA and Large Plasmid DNA from E. Coli and Pseudomonas Aeruginosa

Plasmid Type Concentration (ng/µl)  Yield (µg) 
High copy number small (<10kb) plasmid 359.2 14.4
High copy number small (<10kb) plasmid isolated from Pseudomonas  120.0 4.8
Naturally occurring large (>100kb) plasmid 90.3 3.6
Genomics CosMCPrep Performance Plasmid Purity

Plasmid DNA was isolated using CosMCPrep kit from two E. coli strains; one of the strains carried a high copy small (<10kb) plasmid, and the other strain carried a naturally occurring large (>100kb) plasmid and from P. aeruginosa carrying a high copy small plasmid. The concentration and yield of the plasmid DNA was quantified using the NanoDrop (Thermo Fisher Scientific). The plasmids purity was assessed using the NanoDrop (Thermo Fisher Scientific).

In Figure 1 (right) both the A260/280 and A260/230 ratios for all of the plasmids are within satisfactory ratios for downstream applications. *Acceptable ratios for A260/280 are 1.8 and 2.0 and for A260/230 are 2.0-2.2, but due to varying nucleotide ratios and DNA concentrations the ratios can be higher (ThermoScientific T042-Technical Bulletin).


Mini, Midi, or Maxi Prep all Using the Same Kit

Volume of Overnight (mL)  Average Concentration (ng/µl)  Average Yield (µg)  Average A260/A280  Average A260/A230 
0.8 258 10.3 2.1 2.0
2 1893 74.0 2.2 2.8
5.5 2978 298.0 1.9 2.4

Genomics CosMCPrep Performance Volume OvernightSmall (<10kb) high copy number plasmid was isolated from E. coli. Three volumes of the same overnight growth were lysed and the plasmid was isolated using the CosMCPrep kit. The larger input resulted in linear increase in plasmid concentration.

Compatible plasmid types:

  • Low copy number plasmids
  • High copy number plasmids
  • BACs
  • Cosmids
  • Fosmids
  • Large naturally occurring plasmids


CosMCPrep Requires Less Hands-on-Time

Extraction of Plasmid DNA using CosMCPrep requires less hands-on time and fewer pipetting steps compared to extraction using column-based kits. Figure 3 represents total time to prep plasmids from a sample for 1 to 96 samples using CosMCPrep or a column based kit. At 10 samples, hands on time to prep plasmids is faster using CosMCPrep. The total number of pipette actions (Figure 4), which include dispensing in a sample, mixing a sample, and discarding tips, required for 1, 8, 24, 48, and 96 samples. With the ability to use a multichannel pipette there is significantly less pipette actions that need to take place than with column based kits.

Genomics Genfind v2 DNA Yield Genomics Genfind v2 DNA Purity













Visual Workflow

 Genomics CosMCPrep DNA Plasmid Purification 
  1. Pellet cells
  2. Resuspend cells in RE1
  3. Lyse cells in L2 solution
  4. Add N3 solution to neutralize the lysis
  5. Pellet lysis and transfer the supernatant
  6. Bind plasmid DNA to magnetic beads
  7. Separate magnetic beads from contaminants
  8. Wash magnetic beads with 70% ethanol to remove contaminants
  9. Repeat wash 3 times
  10. Elute plasmid from magnetic beads
  11. Transfer to new plate


CosMCPrep Products for Plasmid Purification

CosMCPrep is available in two kit sizes based on your throughput needs. Click on the specific part number below for purchasing or request a quote. For more information check out our DNA plasmid purification page featuring CosMCPrep.

A37064 CosMCPrep  384
A29174 CosMCPrep  4000



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