Any experience with Soccorex pipettors
John H McDonald
mcdonald at strauss.udel.edu
Thu Sep 1 20:53:52 EST 1994
A year ago, I posted this review of some pipettors that I tried when
setting up a new lab. I still don't like the Socorex; apparently my taste
in pipettors is different from several other posters. You'll be using
these a lot, so don't buy one without trying it out (or at least make sure
you can get your money back if you don't like it).
Socorex Wheaton "Calibra." Changing the volume requires that you push in
the thumb knob and turn it, then turn the adjustment ring to set the first
digit of the volume, then pull the ring up and turn it to set the
remaining digits, then push the ring back down, then turn the thumb knob
to release it. If this wasn't bad enough, this was the heaviest pippettor
I tried (112 grams) and had the stiffest thumb knob (900 g to depress it
halfway). The 1 to 10 ul pipettor I sampled only goes down to 1 ul, so
you'd also have to buy the 0.4 to 2 ul pipettor for anything less. Fisher
and VWR seem to sell this as their "store brand," so the price is
tempting, but you'll regret buying it.
Brinkmann "Eppendorf." The new model Eppendorfs (whitish in color) are a
definite step backwards from the old, black models. Setting the volume
requires that you pull up on the thumb knob, turn it to set the volume,
then push it back in; on the old ones , you just turned the knob. The
first stop on the thumb knob is too stiff, so that pushing the thumb knob
past the first stop to blow out the last bit of liquid is difficult to do
slowly; this would be important if you were loading a gel. This pipettor
is heavy, at 105 g, and has a fairly stiff thumb knob (700 g). The 2-20
ul pipettor I sampled only goes down to 1.02 ul. This is the only
pipettor here that claims to be fully autoclavable, for what that's worth.
The other pipettors here have list prices of around $200, but the
Eppendorfs are closer to $300. They're not worth the extra money.
Oxford "Benchmate." Setting the volume requires that you turn a lock ring
to unlock it, turn the thumb knob to set the volume, then turn the lock
ring to lock it. The thumb knob turns very easily, so it is easy to
accidentally turn it while locking the lock ring. On the other 0.5 to 10
ul pipettors I tried, each turn of the knob is 1 ul, while each turn is
0.4 ul on the Oxford. This makes a large volume change more tedious. The
volume setting does go down to 0.00 on this one. The Oxford is fairly
heavy, at 101 g, but has the easiest thumb knob, at 300 g.
Labsystems "Finnpipette." To set the volume you just turn the thumb knob.
The 0.5 to 10 ul model goes down to 0.4 ul. This is the lightest pipettor
I tried, at 65 g, and it has a fairly easy thumb knob, at 500 g. The
light weight is a little unsettling at first, since we tend to associate
"heavy" with "solid, well-built, dependable," but since the extra weight
in other pipettors is mostly the thicker plastic in their handles, it will
only be important if you frequently use a pipettor as a hammer. Otherwise
light weight is a definite advantage for things like loading a sequencing
gel. [Note--We've used Finnpipettes for the past year and still like them.
Newer Finnpipettes have a different color scheme than the old brown ones,
but I don't know if anything else is different about them. Marsh
Biomedical sticks their label over the Finnpipette name and sells them as
their store brand; the last ad I have gives a price of $134.]
Stratagene "Stratapet." This is either made by Labsystems and sold by
Stratagene under their name, or Stratagene has blatantly copied the
Finnpipette. The Stratapet has a different color scheme (it's pretty
ugly) but is otherwise nearly identical to the Finnpipette.
Gilson "Pipetman." I didn't get one to sample, since I've used them in the
past. There's only one problem with these: it's easy to get your gloves
caught by the volume-adjusting wheel when you're changing the volume.
That problem is annoying enough that I wouldn't want to use them again.
It's particularly annoying when you think that they've been using the same
design for ten or fifteen years, and all they'd have to do is leave a gap
between the volume wheel and the handle, and hide the rubber friction
wheel inside the handle.
MLA pipettor. I tried these at a trade show once and remember thinking
"This is really awkward to use. Don't ever buy one." Now I can't remember
what was wrong with it. The all-metal construction makes them heavy, and
they're expensive, with a list price of close to $300.
John H. McDonald
Department of Biology
University of Delaware
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