The University of Massachusetts Amherst

Analytical Ultracentrifuge Fluorescence Detection System (AU-FDS)

The Analytical Ultracentrifuge Fluorescence Detection System (AU-FDS) accessory for the Beckman XL-A / XL-I instruments compliments the existing detectors.


  • High Sensitivity (picomolar sample concentrations)
  • Large Dynamic Range (approximately four decades)
  • High Selectivity (measures only fluorescing molecules)
  • Higher Throughput (both sample and reference channels can be loaded with sample)

The FDS works as an add-on to existing Beckman analytical ultracentrifuges, old or new. The original Beckman instrument operation is not affected. The AU-FDS utilizes confocal optics to track the location of fluorophores. High-speed electronics measure the entire rotor rotation, allowing all samples to be measured simultaneously.


  • Higher sensitivity and large dynamic range allow determination of tighter binding constants.
  • Very high selectivity due to selection of excitation wavelength (488 nm) allows studies with complex mixtures that traditional detectors cannot handle: heterogeneous binding of proteins with the same molecular weight; serum, cell lysates, et cetera.