The sterilization of rotors and accessories may be desirable to protect humans from pathogens or samples from contamination. Sterilization is a process that eliminates all forms of microbial life, including transmissible agents such as bacteria, viruses, fungi, spore forms, etc.
A widely-used method for heat sterilization is autoclaving, where equipment and other objects are sterilized with hot steam. For instance, a typical autoclaving program is performed at 121 °C and 2-bar atmospheric pressure for 15 to 20 minutes.
All fixed-angle and many swing-out rotor crosses as well as all buckets from Eppendorf have been rigorously tested and approved under these conditions. They also have a special anodized coating, which protects the metal from deeper corrosion effects. Steel swing-bucket rotor crosses with a heat-fixed powder coating are not suitable for autoclaving. If you are in doubt about your rotor, please ask the manufacturer whether autoclaving is possible for that model.
Eppendorf offers a second type of aluminum fixed-angle rotor with a special PTFE coating, which has outstanding chemical resistance against phenol, acetonitrile, DMSO, acetone, trichloroacetic acid, acetic acid and sodium hypochlorite. This coating is applied on top of the actual anodic coating.
In some cases, autoclaving at temperatures of 121 °C for 20 minutes may not be sufficient to sterilize a rotor. Prions, such as those associated with Creutzfeld-Jakob disease, can not be destroyed in these conditions. Some manufacturers state that autoclaving at 134 °C for at least 18 minutes should be sufficient , but in some cases, even this is not enough to deactivate the disease agent, especially when using material with very high infectiousness. Prions generally have a high heat resistance, although their infectivity can be reduced by such a treatment.
A maximum temperature of 121 °C is not suitable for the destruction of prions. Therefore, higher temperatures are necessary. According to available marketing material, only a few rotors on the market can be autoclaved at higher temperatures than 121°C. The customer thus has a very limited choice of available rotors – including Eppendorf’s high-quality aluminum rotors –for these applications. Selected Eppendorf rotors have been extensively tested at 142 °C for 2 hours or 135 °C for 20 min. These Eppendorf rotors can be used with confidence for such applications.