2 replies to this topic

[seanspotatobusiness]

In this protocol, the centrifuge bottles are filled only a half or even a quarter full. Why? Why not 80% or even 100% of the nominal capacity?

Also, the different plastics used to manufacturer the bottles, PPCO, PC, PSF, FEP PTFE... how do I decide? (new ones will be purchased tomorrow for the purpose of preparing electrocompetent bacteria).

Edited by seanspotatobusiness, 25 January 2011 - 11:21 AM.

[seanspotatobusiness]

seanspotatobusiness, on 25 January 2011 - 11:17 AM, said:

In this protocol, the centrifuge bottles are filled only a half or even a quarter full. Why? Why not 80% or even 100% of the nominal capacity?

Also, the different plastics used to manufacturer the bottles, PPCO, PC, PSF, FEP PTFE... how do I decide? (new ones will be purchased tomorrow for the purpose of preparing electrocompetent bacteria).

According to Cole Palmer's website, factors include the clarity of the material (whether you can see through it easily), chemical resistance, spin-speed and subjectability to autoclave: The table here, gives some information on centrifuge tube plastics: http://www.coleparme..._Temp.htm&ID=54

Also, I've read elsewhere that some bottles are actually supposed to be used at least 80% full, and others no more than 75%.

I wonder whether culture is allowed to touch the lid? I can't see why not - it should all be flung to the bottom of the bottle, anyway... Our rotor has a fixed angle.

Edited by seanspotatobusiness, 25 January 2011 - 04:09 PM.

[bob1]

Chemical resistance is a problem if you plan on doing larger scale plasmid preps where you are likely to be adding solvents such as isopropanol (even if it isn't mentioned in a kit, it is still usually there.  I think it is in buffer QC for qiagen kits).