Tracking dyes

  • Tracking dyes are coloured dyes, which are added to the loading buffer/solution.
  • Loading dye/buffer are used to prepare sample for gel electrophoresis.
  • Tracking dyes serve two purposes:
    • They impart colour to the sample, thus visualizing the sample loading process.
    • Since they are visible by naked eye, the progression of gel electrophoresis can easily be monitored.
  • Tracking dyes should have the following properties in order to be used for gel electrophoresis:
    • They should not interact with the components of sample (DNA or protein).
    • They should move from negative to positive electrode (the direction of electrophoresis). Therefore, they should have net negative charge at pH of electrophoresis buffer.
  • Common tracking dyes used for gel electrophoresis: Bromophenol blue, Xylene cyanol FF, Orange G