Quantitative studies of the synchronous excitation method in spectrofluorimetry: Application to tracer concentration measurements in hydrology

Abstract

The detection and measurement by spectrofluorimetry of trace quantities of fluorescent substance is often limited by interference from light at the excitation wavelength. This is the case for the classical tracers (fluorescein, eosin, sulforhodamine G, rhodamine B and WT) used for qualitative or quantitative purposes in hydrology. The need to measure ever decreasing concentrations of these tracers has led to the use of a special method of excitation, the synchronous excication method, in which interference is avoided by scanning excitation and emission wavelengths simultaneously while maintaining a constant wavelength separation between the two. This technique gives a perceptible increase in sensitivity and reduces experimental errors. Spectrofluorimeters equipped with stepper-type motors can be modified cheaply and easily to record synchronous excitation spectra. © 1977.