{HEAD ~ The sonication duration} is preferably less than 15 minutes, {TAIL ~ more preferably less than 6 minutes}, most preferably 60 seconds or less 
is
{ HEAD ~ The sonication duration } is preferably less than 15 minutes , { TAIL ~ more preferably less than 6 minutes } , most preferably 60 seconds or less
HEAD HEAD HEAD HEAD HEAD HEAD HEAD REL OTH OTH OTH OTH OTH OTH TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL TAIL OTH OTH OTH OTH OTH OTH OTH