• My NEB
  • Print
  • PDF
  • FAQ: Is Gel Loading Dye, Purple (6X) or Gel Loading Dye, Purple (6X), no SDS compatible with other DNA binding dyes such as SYBR® and GelRed™ during gel electrophoresis?

    Because high affinity nucleic acid binding dyes can affect DNA migration during electrophoresis, post-staining of gels with SYBR or GelRed dyes is highly recommended. However, these dyes can also be used as precast dyes (into the agarose gel). Because the Gel Loading Dye, Purple (6X) has an increased concentration in SDS, some interference may be observed when using SYBR or GelRed as precast dyes. When using these dyes as precast dyes, NEB recommends using our Gel Loading Dye, Purple, No SDS (6X) (NEB #B7025S ) instead.

    Please follow the recommendations below for both Purple dyes when using SYBR dyes as precast dyes:
    • Reduce the amount of sample DNA loaded to 250 to 500ng, and use 0.5X only of SYBR dyes in precast gels. These dyes are much more sensitive than EtBr. Blown out or smeared bands can be caused by overloading.
    • If using Gel Loading Dye, Purple (6X) B7024S , use TBE instead of TAE buffer, as the SDS interference is increased when using TAE buffer (in the gel and as a running buffer).
    • Use the SYBR dyes as recommended by the manufacturer: add the SYBR dye to the TBE buffer first, then add the SYBR dye/TBE mix to the molten agarose solution.
    • It is preferable to wait a few minutes to add the SYBR dyes to the molten agarose. Adding it to a cooled agarose solution (above gelling temperature, 45°C) produces better results.
    • Always run a freshly made agarose gel, for a single run only. Re-running the gel will yield poor result.
    Please follow the recommendations below for both Purple dyes when using GelRed dyes as precast dyes:
    • Reduce the amount of sample DNA loaded to 60 to 125ng, and use 0.5X only of GelRed dye in precast gels. This dye is much more sensitive than EtBr. Blown out or smeared bands can be caused by overloading.
    • It is preferable to wait a few minutes to add the GelRed dye to the molten agarose. Adding it to a cooled agarose solution (above gelling temperature, 45°C) produces better results.
    • Always run a freshly made agarose gel, for a single run only. Re-running the gel will yield poor result.
    SYBR® is a registered trademark of Life Technologies Corporation
    GelRed™ is a trademark of Biotium