Tim - I would recommend a spectrometer that records entire spectra,
instead of one that takes readings at just 280 nm. Contributions from
light scattering can be very strong and can give results that deviate
from the true value by a factor of two or more. One cannot detect
scattering without recording spectra. The most severe case we have had
was someone who thought the protein concentration was 10 mg/mL (based
on 280) when in reality (after subtraction of the scattering
contribution) it was only 4 mg/mL. Lots of other, less severe cases as
well. Hope that helps. Best - MM
--------------------------------------------------------------------------------
Mischa Machius, PhD
Associate Professor
Department of Biochemistry
UT Southwestern Medical Center at Dallas
5323 Harry Hines Blvd.; ND10.214A
Dallas, TX 75390-8816; U.S.A.
Tel: +1 214 645 6381
Fax: +1 214 645 6353
On Dec 4, 2008, at 9:16 AM, Tim Gruene wrote:
Dear all,
we would like to purchase a UV spectrometer for measuring protein
concentrations (280nm), and I would like to here your comments and
especially recommendations.
We don't need anything fancy, a small, fast device would be
sufficient.
Tim
--
Tim Gruene
Institut fuer anorganische Chemie
Tammannstr. 4
D-37077 Goettingen
GPG Key ID = A46BEE1A
