This request is for funds for the purchase of an Online Instrument Systems (OLIS) RSM 1000 high-speed, stopped-flow spectrophotometer/spectrofluorimeter/circular dichroism spectrometer. The equipment can be rearranged quickly and easily to serve these various functions in either the stopped-flow or steady-state modes. The power of this equipment lies in its unique subtractive double monochromator, which makes possible the acquisition of a full spectrum every millisecond. When operated in stopped-flow mode, the instrument takes a full spectrum every millisecond, thus allowing the investigation to follow spectral changes in real time on a very short time scale. In the customary stopped-flow approach, one is limited to changes in a spectral property at a single wavelength. With a full spectral data set available to the investigator as a function of time, it is possible to a) construct three-dimensional displays of the progress of a reaction with time, b) discover transient intermediates in the reaction pathway that could not be observed otherwise, c) determine the number of species in a kinetic pathway and d) obtain kinetic constants for each of the intermediates in a single experiment that are much more accurate than are available from a series of single wavelength experiments. Because of the plethora of data generated by this approach, up-to-date computational tools are build into the computer software to give very rapid conversions of data into useful results. Thus, both factor analysis and global robust fitting procedures are used for the transformation and analysis of data.
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