Abstract. We report the design, construction and performance of a CCD-based spectrometer system developed to study electronic absorbance spectral changes associated with electron transfer processes in biological systems. The instrument was designed to operate effectively over the 180–1100 nm wavelength range. The temperature of the sample can be controlled between 5 K and above 300 K. When operating between 500 nm and 1000 nm the resolution is ~1.7–2.4 nm and stability better than 0.001 nm, whilst maintaining close to shot-noise-limited noise performance and minimal actinic fluence. Fully reproducible spectra can be taken in a single, gated exposure as short as 100 µs. Illustrative data taken of photosystem II core complexes are presented to demonstrate the spectrometer's ability to monitor complex multi-component kinetics with precision and speed. Laser-flash-induced spectral features, previously requiring laborious point-by-point accumulation and considerable signal averaging, can now be easily seen in a single measurement.

Keywords: CCD, absorption difference spectroscopy, low-temperature

Print publication: Issue 7 (July 2008)
Received 21 December 2007, in final form 28 April 2008
Published 29 May 2008