Removal of PCR inhibitors

Jeff Fairman jfairman at
Wed Nov 24 11:12:09 EST 1999

One thing you want to be cautious about when using that much template in a
reaction is salt carryover from the prep.  We have used the qiagen
nucleotide removal kit with good success when encountering this problem.

Jeff Fairman

Jeff Fairman, Ph.D.
Senior Scientist, Pharmacogenomics Research
Clingenix, Inc.
871 Industrial Road, Suite J
San Carlos, CA 94070
(650) 598-7645 (office)
(650) 598-7641 (fax)
jfairman at

visit: - By Scientists... For Scientists.
jkcarson at wrote in message
<383bddbc.49782822 at>...
>We have been using the guanidinium thiocyanate - diatom method for
>extracting bacterial DNA and has been working well. The extracted DNA
>is used for a 16S rRNA amplification. Our PCR reaction volume is 20ul
>and we use a 1ul template volume. We have modified the PCR format so
>that we can use 9ul of template in the 20ul PCR format - a strategy to
>increase sensitivity. We validated the modification using DNA purified
>by phenol-chloroform.
>If we use a 9ul volume of  template DNA prepared using the guanidinium
>method we do not get any PCR product but if we use a 1ul volume as
>template the PCR works. We have concluded that an inhibitor is
>co-extracting. BSA does not neutralise the effect.
>Does anyone have any suggestions on how to neutralise the PCR
>inhibitor? Has anyone tried GeneReleaser for post-extraction cleanup
>or used alpha-casein to neutralise PCR inhibitors. For various reasons
>we are locked in to the guanidinium-diatom method of DNA extraction.
>Jeremy Carson
>Dept Primary Industry
>Tasmania, Australia
>jeremy.carson at

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