Scanning absorption optical system

Figure 3-7 The scanning absorption optical system of the Beckman Optima XL-A ultracentrifuge. Courtesy of Beckman Coulter.

Figure 5.5.1 Schematic of a modern analytical ultracentrifuge with scanning absorption optical system. [After Cantor, C.R. Schimmel, P.R. 1980. Biophysical Chemistry. Part II Techniques for the Study of Biological Structure and Function. San Francisco W.H. Freeman. Copyright 1980 W.H. Freeman and Company. With permission.]...

This system is a rapid-serial primary screen. It uses a probe to scan from sample to sample across a catalyst wafer, analyzing reaction products at each location via mass spectrometry and/or optical absorption [1, 2, 45, 46]. The mass spectrometer is a commercial quadruple system with a custom ionizer interface. The optical absorption cell is a custom device and uses the method of photo-thermal deflection (mirage) to measure very low levels of a specific analyte. 

This report will discuss the results of a study in which an optical multichannel analyzer (OMA) was coupled to standard spectrometers to record both the UV/VIS absorption and fluorescence emission spectra of complex mixtures of PAH s separated by HPLC techniques "on-the-fly" (i.e., one second spectral scans of the HPLC effluent stream) and stored on a floppy disc for subsequent retrieval and data analysis. The system described has the capability of storing 250 (500 point) spectra and can readily be used to increase the effectiveness of HPLC analysis by allowing both quantitative and qualitative data to be obtained. 

An analytical ultra-centrifugation technique has been used in combination with a scanning optical absorption system for particle size distribution determination. The system was demonstrated for colloidal plulimim 0.4 to 2) nm and unstabilized zinc (4-9) nrn during particle growth [82], A review of examples of colloid analysis of nanosize particles by ultracentrifugation with a focus on multicomonent mixtures has been published.[83]... 

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