Removing endotoxin from plasmid samples by Triton X-114 isothermal extraction.

Triton X-114 temperature transition extraction has been considered to be a simple and cost-effective strategy to eliminate endotoxin from plasmid preparations. However, a repeated cooling–heating process may promote the degradation of plasmid DNA. Based on the finding that the cloud point of Triton X-114 solution increases substantially in the presence of small amounts of sodium dodecyl sulfate (SDS) and that electrolytes decrease the cloud point of Triton X-114–SDS solution drastically, we designed a Triton X-114 isothermal extraction method for removing endotoxin from plasmid samples and found that it has the same endotoxin removal efficiency when compared with the temperature transition extraction method.