Generally speaking, Orange G migrates faster than bromophenol blue, which migrates faster than xylene cyanol, but the apparent " sizes " of these dyes ( compared to DNA molecules ) varies with the concentration of agarose and the buffer system used.
12.
For instance, in a 1 % agarose gel made in TAE buffer ( Tris-acetate-EDTA ), xylene cyanol migrates at the speed of a 3000 base pair ( bp ) molecule of DNA and bromophenol blue migrates at 400 bp.
13.
Even higher levels of bromine ( > 20 ppm ) can result in the secondary conversion of bromophenol red to bromophenol blue with an even lower p " K " a, erroneously giving the impression that the water has an extremely high pH despite being dangerously low.
