Are plasmids purified by Qiagen really that bad?????

Ferland Louis H. ferlandl at ERE.UMontreal.CA
Thu Apr 18 00:48:48 EST 1996

My experience is exactly opposite. As a post-doc, in 1989 or 1990, I did 
a project that involved quite a lot of transfections. I started with CsCl 
preps which were standard in the lab and could generate the fairly large 
anounts of plasmid I required. The transfections results being good but 
not great, and the prep time and ultracentrifuge availability becoming 
issues, I tried the then relatively new Qiagen columns. 

The Qiagen preps 
performed at least 10-fold better per ug than the CsCl preps tested in 
parallel, i.e. I could transfect half as much DNA and get five-fold more 
luciferase or beta-gal activity at the end. I have no reason to think 
that my CsCl prep procedure was defective as they were dialyzed 
extensively the same way as what everybody else I know did, and looked 
the same as everybody else's on gel (very little nicked plasmid). Also, 
most people around me over the years consistently told me they also got 
better results with Qiagen, so your comment surprises me.

I have no experience in in vitro transcription.

No affiliation with Qiagen, Inc. except I wish their stuff wasn't so darn 


On 17 Apr 1996, The Wagner Lab wrote:

> Date: 17 Apr 1996 04:50:55 GMT
> From: The Wagner Lab <ewlab at>
> To: methods at
> Subject: Are plasmids purified by Qiagen really that bad?????
> I've been talking to some people (more dislike it than like it, that's 
> for sure) that really hate Qiagen plasmid preps because apparently the 
> DNA often doesn't work as well as Cs purified for transfections and for 
> in vitro transcription.  Does anyone have any opinions (with experimental 
> support, of course) to the contrary?? 
> I've also seen some sales literature for their endotoxin-free kits-- Does 
> this mean that Qiagen is admitting a problem with purity??  
> Just curious...         Matt (Qiagen tech rep please don't contact me)
> -- 
> 			___________________________________
> 				Matthew Petroski
> 				mdpetros at
> 				(714)824-6953
> 			Molecular Biology and Biochemistry
> 			 University of California, Irvine
> 			___________________________________

Dr. Louis H. Ferland
Centre de Recherche, Hotel-Dieu de Montreal
Dept de Nutrition, Universite de Montreal
Phone: (514) 843-2757     FAX: (514) 843-2719

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