Determining chromium or zirconium content of leather - by measuring X=ray emission and back-scattered intensities, and calibration for the effect of sample density

摘要

The Cr or Zr content of leather is determined by exciting the characteristic X-rays of the metal and measuring the intensities both of this radiation (Ip) and of backscattered exciting radiation (Ir), the measurement being made on a sample of backscattering saturating thickness. The metal content is calculated using a calibration (done once only) based on samples of known density and known metal content, and from determn. of the dependence of the parallel shift of the curves log Ir vs. metal content on the sample density. USE/ADVANTAGE - The Cr (or Zr) content is an essential criterion for the quality of tanned leather. All Cr-in-leather analyses can now be done for a single calibration. The method is based on the fact that Ip is directly proportional to Cr content while Ir is inversely proportional, so that a plot of Ir vs. Cr content varies only according to sample density.