Hi all! While doing my DNA isolation I encountered a new problem. After the addition of chloroform and during centrifugation, the ependorff and 50mL centrifuge tubes melted. Can anyone provide me an explanation for this please!
The centrifugation was carried out for 10 min at 10,000 rpm at 15c
Thank you
Normal eppendorf tubes (made of polypropylene) resist chloroform and most other solvents.
The tubes I use are made of PP. Can it be because of the temperature difference?
Hi Swetha,
That shouldn't happen. PP is polypropylene which should withstand chloroform as well as temperatures (I've thrown mine into liquid nitrogen thne 95 degrees a couple of times).
Are the tubes from the eppendorf brand? Was there possible contamination in the centrifuge that affected the tubes (this would have to be quite excessive)? Any other chemicals in the tubes?
Here is a chemical resistance chart for PP, Chloroform is listed as 'some attack' but.. shouldn't cause melting at 15 degrees for such a short time.
http://www.ineos.com/globalassets/ineos-group/businesses/ineos-olefins-and-polymers-usa/products/technical-information--patents/ineos-pp-chemical-resistance-guide.pdf
Chloroform does not melt eppendorf made of PP materials. Recheck the quality of your tubes because the rpm you used was very minimal to melt the tubes.
Hi Swetha Balakrishnan
This is the problem of your 50 ml tubes, those generally break at high speed. To check this run an 50 ml tube with the same speed filled with the same volume of water.
You can do one thing put a peace of cotton cousin just beneath the tubes and try it.
I have encounter the same problem before.
All the best
Are your tubes 1.5 ml or smaller? If your tubes are too small the centriguge will force them to the bottom of the rotor and they will be deformed. Is the only thing I can think of. I have used tubes from many brands, good and bad ones and that never happened. You need to use adapters for small tubes.
Good luck
I suppose it was not melted, but collapsed due to too much centrifugal force.
Not all the 50 ml tubes can be used at 10,000 rpm.
You'd better check the manufactures' specification before spinning at higher speed than you usually do.
I agree with the comments mentioned before. PP tubes (unless you received the wrong type) are resistant to chloroform or in that respect most other chemicals. Tubes can deform when the bottom is different shape as the 'holders' in the rotor, ie round or U shape vs V shape. 50mL tubes should not be centrifuged above 3500 rpm, certainly not with chloroform. Further it is important to avoid very small volumes in the tubes when using high rpm, this could result in deformation.
Agree with previous answers..I think..its not because of chloroform and due to poor quality of 50ml tubes and in-compatible centrifuge speed. Round bottom 50 ml tubes of Tarson/Eppendroff can be used for DNA isolation for high speed centrifuge upto13000 RPM
HI Swetha Balakrishna, I agree with the comments mentioned before, i had experienced the same problem with tarson's 250ml centrigufe bottle, nowadays the quality of those are not so good, its better to lower the RPM and increase the time for centrifugation.
All the Best .
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