Dr. Grace Dzido, MD is an internal medicine doctor who practices in Roanoke, VA. She is 54 years old and has been practicing for 19 years.
The Loading Dye * Loading dye is a colored buffer mixed with the DNA prior to loading onto the gel. The loading dye contains a relatively high concentration of either glycerol or sucrose. This makes the solution more dense than the surrounding running buffer so that when a sample is pipetted over top of a well it sinks down into the well.
If you are making stock solutions with your dyes remember to re-heat them before you use them. It is normal for some acid dye colors, especially Acid Red 266, to fall out of solution when the water cools, or even to thicken and gel when very concentrated. Heating will restore them.