Free trial of GreenstoneTM 750 for PCR DNA cleanup

Bill Bowers bowers at
Thu Aug 7 16:55:04 EST 1997

   We have developed a high performance reusable microfuge UF membrane concentrator Kit which is 
designed for more cost-effective purification and concentration of proteins (>10 kD) and of 
nucleic acids. Studies with proteins and PCR-amplified 418bp DNA have demonstrated quantititive 
recovery, and a deadstop which absolutely prevents filtration to dryness.  100x concentration of 
up to 750uL can be done in 15-45 min, depending on the membrane pore size selected.  

   We need to characterize the ds DNA bp retention limits of our more open membranes which have 
been shown to retain <95% of globular proteins of 70kD and 150kD, respectively.  This cannot be 
done meaningfully with commercial DNA ladder mixtures, due to the enhanced retention of 
slightly smaller DNA by the polarized retained larger DNA fractions. 
   To that end we are offering 2 free devices preassembled with the 70kD membrane to anyone who 
is doing PCR directed to amplifying DNA in the size range of 60-120bp, and 2 devices assembled 
with the 150kD membrane to anyone amplifying DNA of 100-500bp or >10,000bp.  In return for a gel 
photo showing separation of labled primers from amplified product (eq ladder mixture, unpurified 
PCR reaction, first filtrate, and second TE-buffer-washed retentate) we will offer a credit of 
$60 (half price) toward the purchase of a complete System Kit (4 device sets, tubes and caps, 80 
membranes of up to 4 different retention limit ratings, assembly tool, and a cleaning/storage 
   If you are interested, please Email directly to bowers at with your mailing address 
and we will send devices with an Operating Guide, suggested diafiltration protocol and a 
discount credit certificate.

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