Thermo Scientific 2X RNA Loading Dye is recommended for preparation of RiboRuler RNA ladders and RNA samples for electrophoresis on agarose or polyacrylamide gels. It contains the tracking dyes bromophenol blue and xylene cyanol FF as well as the intercalating dye ethidium bromide. In most denaturing agarose gel systems, bromophenol blue migrates slightly faster than human 5S rRNA, whereas xylene cyanol FF migrates slightly slower than 18S rRNA.