The combination of Raman imaging and LIBS for quantification of original and degradation materials in Cultural Heritage

Abstract

AbstractQuantification with nondestructive techniques is not very well developed in the field of Cultural Heritage despite its interest. In the last decades, several works have been published using Raman spectroscopy for quantifying. However, depending on the methodology used, the information provided by this technique is not complete, and the results could lead to misunderstanding when dealing with unknown samples. In this work, a novel double quantification using Raman imaging (its representativeness would be higher than point‐by‐point analysis) and Laser Induce Breakdown Spectroscopy (LIBS) analyses is presented for analysis of Cultural Heritage samples. Several dolomitic marble samples, with some calcite impurities, covered or not by a calcium oxalate (whewellite, CaC2O4·H2O) layer were analysed in order to optimize the novel methodology. The agreement between the quantitative results from the independent analyses of the Raman Image data and the LIBS data is consistent within the uncertainty arising from both techniques. Further, the same methodology was applied on the same samples but using point‐by‐point Raman analysis with portable instruments, and portable LIBS information, showing again a great agreement between them and with the results obtained using the laboratory instruments.