Raman microspectrometric investigationof urea in calcite and gypsum powdermatrices

Abstract

Raman microspectrometry was used for the nondestructive detection of ureain artificially prepared mineral matrices. Various concentrations of urea, apossible biomarker, mixed with calcite and gypsum powders were analyzed usingthe 514.5-nm line of an argon laser. Two types of measurements were carried out:direct measurements of powders and analysis of the same mixtures throughnatural, transparent crystals of calcite and gypsum. The detection limit forurea in artificial powder mixtures was 1 wt% for both calcite and gypsum. In thecase of measurements through the monocrystals, the detection limit was between1 and 5 wt% for calcite and slightly above 5 wt% in the case of gypsum.Copyright © 2010 John Wiley & Sons, Ltd.