Circular dichroism spectrometer (CD)


Circular dichroism (CD) spectroscopy is a form of light absorption spectroscopy that measures the difference in absorbance of right- and left-circularly polarized light by a substance. CD spectroscopy can be used to analyze the different secondary structural types: alpha helix, parallel and antiparallel beta sheet, turn, and others. The range is 1150 – 165nm.

We use a Chirascan™ CD Spectrometer (Applied Photophysics Ltd) for the measurements.

Click here for more information of the instrument.

Another type of analysis is thermal-denaturation. A series of CD spectra at different temperatures are recorded to study the melting point and thermodynamics of denaturation. Changes on the whole spectra, not only at certain wavelengths, are detected.

The instrument could also be used as a typical UV/VIS/nearIR spectrometer. We have an additional auto-titration unit for titration experiments.

In addition the instrument is equipped with a stopped-flow unit to measure reaction kinetics.

Sample requirements

  • Typically 10mM phosphate buffer is used for far UV ranging up to 180-190nm. Buffers should not contain any groups which absorb in the far UV range.
  • Samples should be in the same buffer as the reference for the baseline. Samples should not contain any “organic solvents” such as glycol, glycerin, DMSO, etc. Sample concentrations should be in a range of 5-100ug/ml. The concentration depends on the protein types. Typically 20-30ug/ml is enough to obtain good spectra. 250-300ul of sample volumes are needed for an 1mm-cuvette.

Click here for more detailed experimental protocols.

Sample submission

Customers inside FBMM are suggested to use the in-house reservation system for the reservation. Customers from outside can fill the submission form and send it to the contact person before the analysis.

Click here for Sample Submission Form.


Academic service price: 35 EUR/hour.

For frequent user, academic self-service, or company service prices please contact Dr. Hongmin Tu.

Acknowledging the BCO core facility

The Oulu BCO core facilities are supported by funding from Biocenter Finland, Biocenter Oulu, the University of Oulu, FBMM, and regional funding.  We kindly ask the users to acknowledge this resource whenever publications are being finalised, for example:

"The use of the facilities and expertise of the Biocenter Oulu biophysical protein analysis core facility, a member of Biocenter Finland, is gratefully acknowledged."

In addition we ask the users to inform us whenever such publications have been accepted for publication.

Contact person:

Dr. Hongmin Tu
Faculty of Biochemistry and Molecular Medicine
University of Oulu
Aapitie 7B, 90014 Oulu, Finland
tel. +358-(0)294 485821
e-mail: hongmin.tu(at)

(Pictures obtained from GE Healthcare, Bionavis, Applied Photophysics and own research, obtained under permission of owners)

Last updated: 5.2.2020