Dear colleagues,
Recently I requested help in describing the ultrasonication energy that our
Vibracell sonicator emitted under our experimental conditions for biofilm
dissintegration. I received several very useful suggestions for which I
thank you. I have finally solved my problem and I thought that some of you
might be interested in the response to the question.
I contacted a Vibracell technician for his advise about the unit in which I
should express the energy and how to get at this value. The unit to use is
Watts/ml that the sample actually sees. If you have a Vibracell or similar
sonicator, this is how you get at the information:
While you are sonicating, the sonicator gives a read out of energy output.
This is the total energy that the sonicator puts out to work at the
amplitude requested and for the fluid you are using. But, the sample does
not see all of this energy as some of it is lost to the air, to the
generator, etc. Hence, you need to determine your in-air losses: ie, you
must determine the minimum amount of energy that the sonicator gives off
when you run it in air for a given amplitude. The Vibracell user's manual
describes how to do this carefully because you can seriously damage a probe
by running it in air for a prolongued time.
Voila!!, the answer to the problem is: the difference between the total
output and the in-air values divided by the volume in which you are
sonicating. Hence, you don't even really need to specify the total volume
in which you sonicate. However, the other parameter that you should
indicate is the duration of sonication.
I hope that this information is useful to some of you out there.
Cindy E. Morris
INRA - Station de Pathologie Vegetale
B.P. 94
84143 Montfavet, France
tel : (33) 490-31-63-84
fax : (33) 490-31-63-35
e-mail : morris at avignon.inra.fr
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