SUBJECT: Spectrophotometers for student use
DATE: 2/95
Biolab Colleagues:
Do you have a recommendation for spectrophotometers for student labs that
you particularly like (or warnings about models you hate)? We have a chance
to apply for some lab modernization funds and would like to replace our
10 year old Bausch and Lomb Spectronic70's, which seem to drift a lot.
Ann Burgess
University of Wisconsin-Madison
At the University of Florida, we've only had B&L Spec 20's for the lab.
They drift a lot also. A few years ago, I made the mistake of buying some
Spec 20D's - the digital machines. We've had some problems with these -
getting weird on us when they are hot, not zeroing at low wavelengths, etc.
I'm going back to analogs.
Kent
*******************************
Kent A. Vliet, Ph.D.
Coordinator of Laboratories
University of Florida
Biological Sciences Program
Gainesville, Florida 32611
Office: (904) 392-1565
Fax: (904) 392-3704
We have been very happy with a digital spec. made by LKB. It's called the
NovaSpec (LKB model 4049). They work well in student laboratories in that
they are stable, will read over a range from 0 to 2 absorbance units and
340 to 640 (or higher) nanometers. They will also accept B-L spec tubes
or regular test tubes or square cuvettes.
Richard Walker
Biological Sciences
Univ. of Calgary
From my experience at the University of Nebraska, I would recommend the
Milton Roy 501 and 601 spectrophotometers. The 501 is visible whereas the
601 is UV/vis. Both are single beam instruments and have microporcessors
to control setting the wavelength and blanking (i.e. no knobs with gears
for students to strip). They use 1 cm cuvettes and the light beam is very
small in profile, so the cuvettes usually need only about 1 cm depth of
liquid. If you want analog output for chart recorders, an extra card will
be required. Digital output is standard. If you want a spectrophotometer
which will scan wavelengths and demonstrate absorption spectra, I recommend
the Shimadzu UV1201. Really a nice instrument, once you get used to the
keypad commands.
--
John Markwell Phone: 402-472-2924
Dept. Biochemistry FAX: 402-472-7842
University of Nebraska Internet: markwell@unl.edu
Lincoln, NE 68583-0718
We used Spec 20's for years and have found that failing bulbs can give rise
to weirdness that may not be expected to arise from the bulb. We have just
purchased about 15 new models and they are behaving very well.
Tom
Tom Haffie Phone: 519-679-2111 (6502)
Department of Plant Sciences FAX: 661-3935
University of Western Ontario e-mail: thaffie@julian.uwo.ca
London, ON, Canada
N6A 5B7
Ann - We had a few of the old B&L Spec 20's to use in our labs and needed
to order more. The Spec 20's still function but many stop probably because
of bulb failure. We ordered the Spec 21 DUV from Milton Roy and so far so
good. It has a digital readout and UV/Visible wavelength range. Also, the
sample compartment can accomodate different test tubes and cuvettes. The
only problem we have had with these new specs is the sensitivity, but it
hasn't been a terrible inconvenience.
Barbara D. Stegenga
University of North Carolina - Chapel Hill
Which models did you purchase? We have just had most of our old Spec 20s
updated with solid state conversion by "Update Instruments," and
have so far been pleased with the results. I was wondering what the price
ranges for the "501s" and "601s" are, and whether its
more cost effective to purchase different machines than to update our old
Spec 20s.
Mike O'Donnell
My apologies for tardiness; I hope this discussion has not yet petered out.
I prefer the digital B&L Spec20 to the analog model. The digitals seem
to be more forgiving to the sort of rough handling students invariably inflict
on any equipment they use. They also allow more precise readings (not necessarily
correct, but they look impressive) and give the students the feeling they
are actually in a modern science lab. The analogs, IMHO, **used** to be
very reliable and seemingly immortal. But the newer (i.e. last 5 years compared
with, let's say 20 years ago) analogs are mechanically and structurally
no better than the digitals and definitely inferior to the old Spec20's
(the plump beige-coloured ones). We have more breakdowns and set-up problems
with machines bought in the last 5 years compared to machines bought 10
to 15 years ago (these still work fine albeit they needed new phototubes).
My feeling is that the digitals' display is too precise, and therefore gives
the impression of instability and inaccuracy. I.e. you are not likely to
notice on the analog the glaring display changes you see on the digital.
Name: Andy Rubaszek
Mail: Department of Zoology, University of Toronto
25 Harbord Street, Toronto, ONT Canada M5S 1A1
Phone: 416-978-3514
FAX: 416-978-8532
UUCP: uunet!attcan!utzoo!andy
INTERNET: andy@zoo.utoronto.ca
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