Hi,
I'm looking to do an endotoxin-free plasmid DNA purification using QIAGEN EndoFree plasmid maxi kit. I need to use endotoxin free pipette tips and tubes for this. For the centrifugation steps I need to use 50 ml Nalgene centrifuge tubes. How do I ensure these are clean and endotoxin free?
Thank you in advance,
Emma
Hello Emma Parsons
Contaminants such as endotoxins are difficult to remove by any sterilization method. So it is very important to prevent contamination during manufacturing. The absence of these contaminants is separately tested, usually by a third-party laboratory. Sterilization after manufacturing ensures that the pipette tips and tubes do not contain any microbial life (bacteria, viruses etc.) when delivered to customers.
Although the high temperatures used in producing laboratory plasticware will usually eliminate any contaminating endotoxins, these can subsequently be reintroduced during the handling associated with assembly and packaging.
By choosing plasticware that is certified by the manufacturer as having been endotoxin-tested and proven to be below a defined level (typically
In addition to the above comments, endotoxin can be difficult to remove completely, because E. coli extracts contain a whopping amount of it. It is therefore advisable to check the concentration of endotoxin in your preparation by performing an assay with some of the commercially available endotoxin detection kits.
not trivial to remove them from the used pipets/tubes (need high temp treatment for eg glass, or certain chemicals). You dont need to have clean plastics/glass for most of the plasmid prep workflow, just for the final step and elution. so definitely use single use plastics when possible- either certified endotoxin/pyrogen free, or regular single use plastics from a reputable vendor (which is usually fine). If using glassware- wash it intensively, and bake o/n at max temp