Details are given for construction of a sensitive spectrophotometer whose components include a double monochromator for achieving a high spectral purity in the detecting beam and a feedback circuit for stabilizing the light emitted from the detecting beam source. The instrument is capable of quantitatively measuring changes as small as 5×10-5 absorbance unit, has a resolution of 1 A. over much of the spectrum (2600 to 12000 A.), and can measure precisely kinetic parameters which may vary from 10-4 second to minutes. Typical light-induced absorbance changes for the photosynthetic bacterium Rhodospirillum rubrum are presented, and the importance of using a low intensity detecting beam for such systems is underscored.
ASJC Scopus subject areas
- Analytical Chemistry