these amplicons were fragmented by sonication in the presence and in the absence of the marker to 10 u03bcl of pcr reaction there are added 2 u03bcl of meta biopmdam 100 mm in dmso the volume is adjusted to 100 u03bcl with pure water the ph is adjusted to 6 5 the mixture is incubated for 30 min at 60 u00b0 c in a bath of an ultrasound vessel frequency 35 khz model t460 h bioblock france b labeling during chemical fragmentation of the pcr amplicons single step reference protocol to 10 u03bcl of pcr reaction there are added 50 u03bcl of sodium formate ph 3 50 mm and 2 u03bcl of meta biopmdam 100 mm in dmso the volume is adjusted to 100 u03bcl the solution is incubated for 30 min at 60 u00b0 c the trials are carried out in duplicate so as to be able to analyze the fragmentation of the dna on a gel and the efficiency of labeling by hybridization and reading of the dna chip as described above example 9 on phycoerythrin detection the analysis was carried out on a denaturing polyacrylamide gel 8 polyacrylamide 7 m urea 1 u00d7 tbe using ethidium bromide staining gel analysis shows that the dna amplicons are fragmented by sonication at 60 u00b0 c the results in table 10 of labeling during sonication conditions a are satisfactory this shows that physical fragmentation by sonication of the dna targets is compatible with the chemistry of labeling with labeling reagents carrying a diazomethyl functional group the weak labeling results in this case are certainly due to the fact that the marker becomes degraded.