Desalting minimal amounts of DNA for electroporation in E. coli: a comparison of different physical methods.

Recovery and purification of ligated plasmid DNA is a critical and limiting step in modern molecular cloning techniques prior to electroporation in E. coli. Four different DNA purification and desalting methods were compared in regard to simple handling, reproducibility, efficiency and cost-effectiveness using picogram and nanogram amounts of DNA. Microcolumn purification of DNA was up to two orders of magnitude more efficient compared to gel filtration, ethanol precipitation or drop dialysis.