It is ridiculous, I know, but I can't seem to find a simple Salting Out DNA extraction protocol for small volumes. Some people close to me use them for large volumes (5ml) but not a single one for small volumes (500-800 ul) of blood.

I need to use some devices that cannot be used with phenol extracted DNA (Q-TOF, dHPLC) and also want to end all the phenol extraction procedure (it is time consuming, hazardous and the phenol is not colected for a long time, so we end up with bottles and bottles of the stuff in the lab).

I want a simple salting out protocol, with in-lab prepared solutions, and most importantly, quantites of each one of them, as their proportion change significantly from large to small volumes.

Many thanks,
Nelson

Hi Nelson!

Surely salting out will mean that you have SDS and NaCl left? Both will upset the big grey boxes you want to run your samples on.

I would recommend a crude extraction followed by running the DNA over spin columns. You can get blood DNA extraction kits. I know you think homemade stuff is probably cheaper, but I find kits to be easier, more reliable and hence faster - thus saving you time. The most expensive resource in a lab is you, the worker.

I was involved in a project about three years that could have been taken in the direction of MALDI-TOF genotyping, but didn't. Anyway when we looked into DNA preparation, it appears only the purest DNA will do - and salting out isn't that great

BTW, I don't work for a DNA extraction kit company

As far as I know (or been told) phenol extracted DNA cannot be used with those devices, as it (the remaining phenol) will stick to the filtration column and spoil them. At least, that's what a friend of mine who used to be responsible for the department dHPLC told me, and she forbade everyone who used phenol, and recomendend the salting out. Unfortunatelly she is abroad now and I also am in another University, and they (my old lab) use the large volumes protocol. Here tehy use only phenol.
I don't want to (or rather, cannot afford to) use kits because money is really an issue, but fortunatelly I have someone to do the extraction for me (at least, most of them) because I will use all of the available DNAs in the lab, not one exclusive for me. There will be large amounts of samples, just for me some 500-600, and weekly there are some 30-50 for the whole group. We would spend a fortune on DNA extraction kits, and woudn't have money for the enzymes
I plan on using dessalting post-pcr methods prior to the big grey boxes, specially MALDI, for wich there's no real problem with phenol.
Besides, the idea is to cut of the use of phenol for everything possible (bones and sample tissues is another matter)

Oh, and they won't let me use phenol extracted DNA in the brand new Q-TOF, so there's really no alternative - seeing that kits are out of the picture.