Best centrifuge tubes for use with Qiagen 500?

Sailesh Surapureddi SaiSu at MCB.LiU.SE
Fri Jun 16 03:48:50 EST 1995

>To: methods-and-reagents at
>From: dobates at (Dave Bates)
>Subject: Best centrifuge tubes for use with Qiagen 500?
>Date: 14 Jun 1995 23:39:11 GMT
>What are people's opinions on the best tubes to precipitate the plasmid
>DNA after elution from a Qiagen tip 500.  I've been using Nalgene Oak
>Ridge tubes, both the Polycarbonate ones (which split on me too often
>for comfort - another two went today and that makes five out of the 10
>pack in the last 4 months), and the polypropylene ones in which you can
>hardly see the pellet. I don't like using these large tubes as you end
>up with a small, hard to see pellet in the bottom of a large volume
>container. Does the isopropanol stage really need to be spun at 15,000g
>to get a good pellet or can I spin it at a lower speed and use
>something like a Falcon 50ml tube at 9000g? Can you just add 35mls 100%
>Ethanol and get a nicer pellet, or is there not enough salt there?
>What is everyone's favourite.
>A very pissed off Dave
>Dave Bates PhD                                     Tel: 916 752-7081
>Postdoctoral Researcher                            Fax: 916 758-2554 
>Dept of Human Physiology                         email:
>dobates at
>University of California at Davis                drink: anything
>Davis, California 95616, USA            No I don't have a sense of
>                                                now buy me a beer      

Hi Dave,
	I am afraid you and me are sailing in the same boat. But what I am currently 
doing is to spin the isopropanol mix in JA 20 (50mL) of Beckman tubes, with the 
outer ending marked, in this you can see a pellet, but ofcourse it depends on 
the amount of culture you have started with, 500mL and you should be able to see 
the  pellet. 
		The other point is using 35mL of 100% Et-OH, this does not help since it 
contaminates the DNA with protein which ppt along with your DNA and cannot be 
used as pure prep, but if you want to try this, then why bother with Qiazen 500, 
you can use Lysozme or alkaline hydrolysis and then phenol, iso propanol and 
Et-OH ppt your DNA. Saves money, doesnt it.

All the best

Another Sailor

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