Development of multiwavelength absorbance optics (MWA)

The idea of replacing the traditional absorbance detector with a spectrometer was first published by Helmut Coelfen's group at the Max Planck Institute of Colloids and Interfaces in 2008 [1]. Prof. Coelfen presented the prototype of a detector arm carrying a spectrometer as a detector after light containing the entire spectrum would pass through the measurement cell. The entire assembly could be radially moved on a sliding rail, collecting data along the radial coordinate.

Controlling and data acquisition was performed via LabView interface. However, some problems were observed, especially in respect to timing issues. This encouraged Nanolytics, working on the advanced interference detector at that time, to develop an independent multiplexer with an own microcomputer – not dependent on any Windows based controlling computer. This unit was later named “omega device.”

Parallel to Prof. Coelfen's group, Nanolytics implemented enhancements on the original MWA design. In 2015, advanced MWA versions from both groups were featured in a publication [2]. While the timing problems had been resolved following different paths (with 32bit Labview by Prof. Coelfen and with the omega device at Nanolytics), both systems exhibit different qualities, as caused by the different system architecture.

A first MWA centrifuge manufactured by Nanolytics was purchased by a university in 2014.

Of course, an MWA Analytical Ultracentrifuge (AUC) is also operated by Nanolytics for service measurements.


[1] Strauss HM, Karabudak E, Bhattacharyya S, Kretzschmar A, Wohlleben W, Coelfen H, Colloid Polym Sci (2008) 286:121–128

[2] Pearson J, Krause F, Haffke D, Demeler B, Schilling K, Coelfen H: Next Generation AUC (1): Multi-Wavelength Detectors for the Analytical Ultracentrifuge add a Spectral Dimension to AUC instrumentation, Methods in Enzymology, ed. J. Cole, 2015, in press