Product Class: Other

Gel Loading Dye, Purple (6X)

Product Introduction

Gel Loading Dye, Purple (6X) is the premier gel loading dye from NEB for sharp, tight bands.

  • No UV Shadow
  • Contains Ficoll® for brighter, tighter bands
  • Contains SDS for improved band sharpness
  • Contains EDTA to stop enzymatic reactions
  • Compatible with agarose and non-denaturing polyacrylamide gels
  • Our Purple Gel Loading Dye sharpens bands and eliminates the UV shadow seen with other dyes. Available with or without SDS (NEB #B7025).

Catalog # Size Concentration
B7024S 4.0 ml 6 X

Product Information


Gel Loading Dye, Purple (6X) is a pre-mixed loading buffer which contains a combination of two dyes, Dye 1 (pink/red) and Dye 2 (blue). The red dye serves as the tracking dye for both agarose and non-denaturing polyacrylamide gel electrophoresis. The two dyes separate upon gel electrophoresis; the red band is the major indicator and migrates similarly to Bromophenol Blue on agarose gels. Specifically chosen, this dye does not leave a shadow under UV light. This solution contains SDS, which often results in sharper bands, as some restriction enzymes are known to remain bound to DNA following cleavage. EDTA is also included to chelate magnesium (up to 10 mM) in enzymatic reactions, thereby stopping the reaction. The dye also contains Ficoll, which creates brighter and tighter bands when compared to glycerol loading dyes. This product is packaged as 4x1 ml vials.

Attention SYBR® Safe and GelRed™ dye users: Due to an increased concentration of SDS* in B7024S, NEB recommends using Gel Loading Dye, Purple, No SDS (6X) (NEB# B7025S) instead.

*Compared to NEB# B7021 and NEB# B7022.

Comparison of dye fronts
Comparison of dye fronts
Nucleic acid samples were run on an agarose gel, with either Purple or Blue loading dyes. Both dyes ran at the same speed.
UV shadow comparison
UV shadow comparison
The new Gel Loading Dye, Purple (6X) (Lane 1) included in the Quick-Load Purple 1kb DNA Ladder does not cast a UV shadow over the underlying bands, unlike the Gel Loading Dye, Blue (6X) (Lane 2).
This product is related to the following categories:
Gel Loading Buffers,
Quick-Load Purple DNA Ladders Products,
Buffers Products,

Reagents Supplied

Reagents Supplied

The following reagents are supplied with this product:

NEB # Component Name Component # Stored at (°C) Amount Concentration

Properties & Usage

1X Buffer Components

2.5% Ficoll®-400
10 mM EDTA
3.3 mM Tris-HCl
0.08% SDS
0.02% Dye 1
8.0E-4% Dye 2
pH 8@25°C


  • No UV shadow allows for publication grade images
  • Brighter, sharper bands vs. glycerol-based loading dyes
  • Stops enzyme reactions

Product Notes

  1. Use 5 μl of Gel Loading Dye, Purple (6X) per 25 μl reaction, or 10 μl per 50 μl reaction. Mix well before loading gel.
  2. Attention SYBR® Safe and GelRed™ dye users:
    Due to an increased concentration of SDS in NEB #B7024, NEB recommends using Gel Loading Dye, Purple, No SDS (6X), NEB #B7025 instead.

Protocols, Manuals & Usage


  1. Protocol for All DNA Loading Dyes (B7024)

FAQs & Troubleshooting


  1. Does the Gel Loading Dye, Purple have any advantages over the traditional Blue Loading Dye?
  2. How many bands of color should I see on the gel?
  3. I cannot see the blue dye when I run it on a gel. Why not?
  4. Why is there SDS in the dye?
  5. Can I use the Gel Loading Dye, Purple with the QIAquick Gel Extraction Kit?
  6. 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?
  7. Can Gel Loading Dye, Purple 6X (B7024) be stored in cold temperatures?
  8. How are the 6x loading dyes packaged?

Quality, Safety & Legal

Quality Assurance Statement

Quality Control tests are performed on each new lot of NEB product to meet the specifications designated for it. Specifications and individual lot data from the tests that are performed for this particular product can be found and downloaded on the Product Specification Sheet, Certificate of Analysis, data card or product manual. Further information regarding NEB product quality can be found here.


The Specification sheet is a document that includes the storage temperature, shelf life and the specifications designated for the product. The following file naming structure is used to name these document files: [Product Number]_[Size]_[Version]

Certificate Of Analysis

The Certificate of Analysis (COA) is a signed document that includes the storage temperature, expiration date and quality controls for an individual lot. The following file naming structure is used to name these document files: [Product Number]_[Size]_[Version]_[Lot Number]

Safety DataSheets

The following is a list of Safety Data Sheet (SDS) that apply to this product to help you use it safely.

Legal and Disclaimers

Products and content are covered by one or more patents, trademarks and/or copyrights owned or controlled by New England Biolabs, Inc (NEB). The use of trademark symbols does not necessarily indicate that the name is trademarked in the country where it is being read; it indicates where the content was originally developed. The use of this product may require the buyer to obtain additional third-party intellectual property rights for certain applications. For more information, please email [email protected].

This product is intended for research purposes only. This product is not intended to be used for therapeutic or diagnostic purposes in humans or animals.

New England Biolabs (NEB) is committed to practicing ethical science – we believe it is our job as researchers to ask the important questions that when answered will help preserve our quality of life and the world that we live in. However, this research should always be done in safe and ethical manner. Learn more.


SYBR® is a registered trademark of Life Technologies Corp.
GelRed™ is a trademark of Biotium.