A NEW CALIBRATION PROCEDURE FOR FLUORESCENCE MEASUREMENTS OF SEDIMENTARY ORGANIC-MATTER

A new microspectrofluorimetry calibration method has been developed by three laboratories. It allows quantification, in terms of spectral radiance, of the fluorescence emitted by oils and kerogens. Specifically, it uses a source consisting of a quartz-iodine lamp illuminating an opalin glass, which diffuses by transmission according to Lambert's Law. The equipment has been designed and constructed in the Elf Aquitaine laboratory. This source, called ESS, is a spectral radiance standard calibrated by a standardization Institute (Laboratoire National d'Essais-LNE Paris). It can be used either to calculate the relative correction function or to calibrate the photo-optical system with a view to obtaining fluorescence measurements expressed as spectral radiance units. The results obtained from the tests carried out by three laboratories in relative mode are encouraging: values are within a small variation range, anomalies can be explained; this calibration apparatus is considered inexpensive, easy to use and to duplicate. This new calibration method actually provides organic petrographers with new tools capable of increasing the scope of fluorescence measurements that are for the time being neigher comparable nor reproducible.