Message-Id: <v02140b0baf15815024d7@[134.197.50.216]>
Date: Wed, 29 Jan 1997 14:46:07 -0800
From: schooley@unr.edu (David A. Schooley)
Subject: Re: "SpeedVac",Vacuum concentrators
To: Recipients of ABRF List <abrf@aecom.yu.edu>
Michael and others who posted on this subject,
In late 1995 there were a number of postings in this forum about
the HETO vacuum concentrators made in Denmark. On the basis of
out-of-forum E-mails, we decided to purchase a HETO concentrator system,
as we have experienced reliability problems with Savant equipment in the
past, especially the cold traps.
We are delighted with the cold trap made by HETO (-105 deg C),
which does not requrie a glass insert. However, there is a design flaw in
the HETO concentrator compared with the Savant Speed Vac 200. The speed of
rotation is much lower, probably 1/2 to 1/3, and the radius of the rotor
is less. Consequently, when we use the HETO head which holds 12 50 ml
polypro centrifuge tubes for fractions from prep reversed-phase, we have
had serious bumping problems due to the significantly lower G force
generated by the HETO.
We finally solved this by pre-cooling fractions in liquid N2 before
putting them in the HETO. Otherwise, if over 1/2 full, they will bump!!
It is a shame that HETO does not use a higher speed of rotation so that
the centrifugal force really has a chance to work.
David
David A. Schooley
Dept. of Biochemistry/330
Univ. of Nevada
Reno, NV 89557
schooley@med.unr.edu
tel: (702) 784-4136; fax (702) 784-1419