Dear All, First of all, is it possible to calculate the concentration of metal (loading, therefore) from just the edge jump? Is there a simpler equation like knowing the Flux values or some basic instrumental information we can calculate the concentration term using Io and It values of beamline (the simplest form of Beer-lambert law)? if so what formula should we use. I searched in the mailing list archive and have found one such archive but it discusses how to use calculation to find out how much sample would be needed to get the edge jump. I am rather interested in the reverse way. I have an experimental edge jump and want to calculate (if possible with as much accuracy as possible) the concentration of metal. I know with only edge jump it will be difficult and XRF will be a better and more reliable way. But for better understanding and cross checking between different samples, I wish to do such calculations. Can anyone guide me to the right direction and equations to do such calculations? Thank you all in advance Warmest regards Pushkar -- Best Regards, Pushkar Shejwalkar. Post-doctoral -Researcher, Tokyo Engineering University, Tokyo-to Japan