Optimizing resolution in constant-energy synchronous spectrofluorimetry

Constant-energy. synchronous luminescence (CESL) offers significant improve ments in selectivity and sensitivity compared to the more conventional cons tant-wavelength synchronous luminescence (CWSL) technique. Despite this con sideration, practical problems can be encountered that have not been report ed in the literature. This paper offers an explanation of these technical i ssues-why they occur and how they can be avoided-and the method optimized t o take full advantage of this powerful technique. Polycyclic aromatic hydro carbons (PAHs) were selected for demonstrating all our conclusions, because of their carcinogenic activity; 16 of them appear in the EPA (Environmenta l Protection Agency) List as PAHs for which it is necessary to develop effi cient methods for their precise and accurate quantification at low levels. The technique can be applied to other complex fluorescent mixtures.