Raman spectroscopy of uranium compounds and the use of multivariate analysis for visualization and classification. (June 2015)

• Record Type: Journal Article
• Authors: Ho, Doris Mer Lin; Jones, Andrew E.; Goulermas, John Y.; Turner, Philip; Varga, Zsolt; Fongaro, Lorenzo; Fanghänel, Thomas; Mayer, Klaus
• Is Part Of: Forensic science international. Volume 251(2015)
• Page Start: 61
• Page End: 68
• Publication Date: 2015-06
• Subjects: Nuclear forensics -- Raman spectroscopy -- Uranium ore concentrates -- Multi-variate analysis; Medical jurisprudence -- Periodicals; Chemistry, Forensic -- Periodicals; Forensic Medicine -- Periodicals; Médecine légale -- Périodiques; Chimie légale -- Périodiques; Gerechtelijke geneeskunde; Gerechtelijke chemie; Gerechtelijke psychiatrie; Chemistry, Forensic; Medical jurisprudence; Electronic journals; Periodicals; Electronic journals; 614.1
• DOI: 10.1016/j.forsciint.2015.03.002
• Languages: English
• ISSNs: 0379-0738

Abstract

Highlights: 95 Raman spectra of uranium ore concentrates were analyzed by PCA, PLS-DA and FDA. PCA, PLS-DA and FDA showed consistent and corroborating results. Some samples of ADU and UH could not be distinguished from each other. Other classes of compounds were generally well separated. Abstract: Raman spectroscopy was used on 95 samples comprising mainly of uranium ore concentrates as well as some UF4 and UO2 samples, in order to classify uranium compounds for nuclear forensic purposes, for the first time. This technique was selected as it is non-destructive and rapid. The spectra obtained from 9 different classes of chemical compounds were subjected to multivariate data analysis such as principal component analysis (PCA), partial least square-discriminant analysis (PLS-DA) and Fisher Discriminant Analysis (FDA). These classes were ammonium diuranate (ADU), sodium diuranate (SDU), ammonium uranyl carbonate (AUC), uranyl hydroxide (UH), UO2, UO3, UO4, U3 O8 and UF4 . Unsupervised PCA of full spectra shows fairly good distinction among the classes with some overlaps observed with ADU and UH. These overlaps are also reflected in the poorer specificities determined by PLS-DA. Higher values of sensitivities and specificities of remaining compounds were obtained. Supervised FDA based on reduced dataset of only 40 variables shows similar results to that of PCA but with closer clustering of ADU, UH, SDU, AUC. As a rapid and non-destructive technique, Raman spectroscopy is useful and complements existing techniques in multi-faceted nuclear forensics.