Science for Health
The Institute has two analytical ultracentrifuges located in the Division of Physical Biochemistry. These instruments provide first-principle hydrodynamic and thermodynamic information concerning the size, shape and association state of macromolecules.
For basic applications, the two instruments (XL-A and XL-I) are equipped with UV/Vis optics that record radial absorbance measurements and monitor evolving (sedimentation velocity) or static (sedimentation equilibrium) concentration gradients. The XL-I is additionally equipped with Rayleigh interference optics that measure concentration profiles directly from solute refractive index gradients. The interference and absorbance data are recorded simultaneously in the XL-I and are used in combination for the analysis of complex associating systems.
The optical detection system of the XL-I analytical ultracentrifuge consisting of a combined UV/Vis spectrophotometer and laser interferometer is shown in the bottom image. A fringe displacement pattern produced by a moving concentration boundary measured by the Rayleigh interference optics of the XL-I is shown above.
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