Construction and performance of a scanning, photon-counting spectrofluorometer

Abstract
A photon‐counting spectrofluorometer interfaced to a Nuclear Data ND 812 computer was constructed to facilitate acquisition of emission spectra at very low signal‐to‐noise ratios. The photon‐counting technique combined with repetitive scanning permits the detection and quantitation of emission from strong fluorophors near the picomolar level. The computer performs a variety of digital manipulations such as subtraction of background, normalization of spectra, corrections for instrument response, and polarization calculations. Special attention needs to be given to handling of cuvets and solvents to minimize background signals.