Analysing Dyes Through Gel Electrophoresis

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Analysing Dyes Through Gel Electrophoresis


Early in the 19th century, scientists worked with the basic principles of electrophoresis. Scientists measured the behaviour and properties of small ions moving through solutions in an electric field. In the 1930s, Arne Tiselius developed the Tiselius apparatusfor separating protein molecules through electrophoresis. By the 1960s, many different gel electrophoresis methods made it possible to separate different molecules, driving the rise to molecular biology.

Gel electrophoresis is the process by which molecules can be separated by size and electric charge through the application of an electric current. The strength of the current moves molecules through the pores of a thin layer of the gel, a firm jelly-like substance. The gel can be made so that its pores are only the right dimensions for separating molecules with a specific range of sizes and shapes. Smaller fragments usually travel farther than larger ones. In this experiment, a gel was used to separate the six tracking dyes; Bromophenol Blue, Crystal Violet, Orange G, Malachite Green, Xylene Cyanol and Dye Mixture. The gel that was used to separate the tracking dyes was agarose gel.

In the first part of the lab, the agarose gel was poured into the tray while a gel comb was inserted in the center and was rested for twenty minutes until the gel partially solidified. The comb was then removed from the gel and the gel ended up with eight wells. Each well was assigned with a specific tracking dye. After the tracking dye was placed into the wells, the tray was placed into an electrophoresis chamber which contained 1X TBE running buffer. Once the trays were in the chamber and the chamber was covered, the machine was plugged into a power supply and was set to 110V. After approximately 10 minutes, the tracking dyes started to move towards the negative poles and the positive poles of the tray. Therefore, the purpose of this investigation was to separate the tracking dyes and determine their molecular charge. The experiment displayed how fragments were separated based on their size, which in turn affected how fast they were able to move through the gel.


This experiment will help us have a better understanding of the process and the purpose of the gel electrophoresis. In addition, this experiment will provide us more knowledge on how DNA reacts in the process of gel electrophoresis and it will also determine the polarity of the tracking dyes.

Gel electrophoresis is the process in which molecules can be separated by size and polarity by the application of an electric current while the molecules are in the gel. In the 1930s a scientist named Arne Tiselius changed the world of science with the discovery of electrophoresis (The Columbia Electronic Encyclopedia, 2004). Before this invention was represented, the basis of DNA separation was already discovered. In the 1800s, Wilhelm, Nernst and Kohlrausch performed an experiment in which the measurement of minuscule ions' properties was involved as they made their way through a variety of solutions treated by electrical fields (Smithies, 2009). Kohlrausch used the some of the experiments to determine equations for all concentrations of the charged particles that went through the solution.

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In 1937, the Tiselius Apparatus was created and developed by Arne Tiselius (The Columbia Electronic Encyclopedia, 2004).  The Tiselius Apparatus was an important factor to the rise of electrophoresis, however, it was not able to completely separate the substances that looked like each other until the 1940s. This was due to the fact that the gels and solids tuned out to be commonly used as mediums instead of the traditional solutions.

Since the 1940s, major changes have been made to electrophoresis which lead to a variety of new methods. Today, there are numerous gels that are used, for instance, Agarose, ...

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