Covaris sample volume

[amed1552]

Is anyone else having problems pipetting samples into the Covaris microTUBES? I've been frequently seeing air bubbles (presumably the result of surface tension) displace my sample out of the tube as I try to add it--this poses a contamination threat. Does anyone have a trick for avoiding this?

One possible fix is decreasing the volume added to the tubes. Are the suggested 130µL necessary? Has anyone tinkered with lower volumes?

Thanks!!

[Hamid]

Hi Amed,

The best way to place your sample inside the Covaris micrTUBEs is to go through the septa with a p200 pipette tip. Once inside the tube, you then angle the tip slightly such that it is touching the side of the tube and dispense your sample. You should also slowly take out the pipette tip as you are dispensing the 130ul volume alongside the inside wall.
If you take a look at the link http://covarisinc.com/wp-content/uploads/pn_400103.pdf you will note that Covaris also provides shearing settings for processing samples in 50ul volume.

Thank you

hamid

[wjeck]

I have heard that some folks spin their tubes at low speed to get the bubbles out, but I think this works best if you are using the Covaris plate system instead of the individual tubes.

[NextGenSeq]

We have sheared down to 25 ul volumes. Covaris told us to not go below that or the shearing results will be less consistent.

[Élodie]

I use Covaris for TruSeq DNA sample preparation. According to the protocol, I use 52,5 ul of sample in a Covaris microtube. To know how to dispense the sample in the tube avoiding bubbles, i agree with Hamid. You can also do a quick spin before the shearing.

[Mindbomb]

It works fine if you hold the tube at an angle. Alternatively I have used the narrow tips made for Western blot loading.