How to set the Sonicator to 20%amplitude? - (Feb/17/2012 )

Hi all,

I have to sonicate c. elegans for a Genomic DNA prep. The protocol asks for for 30 pulses at a 20% amplitude. I'm using a Fisher Sonicator Dismembrator model 100, and I'm not sure how to set it up to 20% amplitude. There's a knob (0-10) but I would like to know which number correspond to 20% amplitude...


Thanks for any help or suggestion
:-)

Read the manual...

there's no manual!!! that was the first thing I looked for... Otherwise I would not been asking!!!!

Unfortunately, there is no easy or standard way to quantitate sonication conditions. Every sonicator is different. It probably doesn't make a lot of difference, as long as you sonicate long enough and hard enough, and keep the suspension cool. I'd start with a low setting and alternate soncation and putting the worms on ice, perhaps 30-60 seconds of sonication and 2-3 minutes on ice.

Some sonicators now report the wattage of the delivered ultrasound, which really is the important number, but very few do this.