Wash solution and method for purifying sequencing reaction product. The
wash solution comprises an effective amount of guanidine in a low ionic
solution to reduce or eliminate the presence of dye terminators in a
sequencing reaction product In its method aspects, the present invention
comprises the addition of the wash solution to the sequencing reaction
product prior to filtration, followed by filtration to reduce or
eliminate unincorporated dye terminators. The purified sequencing
products can then be resuspended and transferred to an appropriate
substrate for sequencing or further preparation. Dye blobs formed from
unincorporated dye terminators no longer interfere with the
electropherograms generated upon electrophoresis of the sample.