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Old 09-19-2014, 08:36 AM   #1
Leo Lee
Junior Member
Location: HK

Join Date: Apr 2014
Posts: 5
Default NEBNext® Ultra™ DNA Library Prep QC- extra peak at around 1500bp

I used the NEBNext® Ultra™ DNA Library Prep for illumina to prepare the library and follow the standard protocol with 250ng DNA input, 8 PCR cycle and size selection for target total library size ~400bp.

However, I noted that quite a number of samples in the same preparation showed an extra peak at around 1600bp (slightly >1500bp, refer to the attached Bioanalyzer profile lanes 4, 5, 7 to 11).

From some forum discussion, a extra peak at 1500bp might be due to the carryover of magnetic beads. However, the peak in my libraries is not that strong and board compared with the typical magnetic bead leftover bioanalyzer profile.

Is the extra peak a single-stranded artefact? Do you think it will affect the sequencing of the library? Any another round dual bead size selection is needed to remove that extra peak?

Thanks very much for your comment.
Attached Files
File Type: pdf Bioanalyzer profile.pdf (24.5 KB, 43 views)

Last edited by Leo Lee; 09-19-2014 at 09:08 AM.
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