help with consostent DNA yields from phenol/chloroform extractions - (Jan/16/2006 )

[font=Arial][size=7]HI all--I work at a biosafety testing facility. We are having problems with consistent DNA yields using phenol/chloroform extractions. All samples are run in triplicate on the ABI 7500 and our results are all over the place. For example, if we run 3 tubes, each in triplicate, the average of tube one is roughly 10 pg, tube two is 450 pg, and tube three is 800 pg and all three original tubes were spiked with 1000 pg k12 E. coli DNA befor DNA extraction was begun. Does anyone know of any kits or can give any advice that that can help us?
Thank you,
Don

You are using very low DNA levels (at least for normal Mol Bio experiments) soyour DNA may be "sticking" to your tubes, tips, etc. You might want to think about adding a carrier like tRNA.