A new selective technique for characterization of polycyclic aromatic hydrocarbons in complex samples: UV resonance Raman spectrometry of coal liquids.
Evidence is given showing that UV resonance Raman spectroscopy (UVRRS) is a powerful technique for the identification and quantitation of polycyclic aromatic hydrocarbons (PAH's) in a coal liquid. Results suggest that this technique will be of general utility for the study of systems containing chromaphoric species absorbing in the UV spectral region. In this paper it is demonstrated that (1) the resonance Raman spectra of PAH derivatives can be selectively observed in solutions of coal liquids and (2) different UV excitation wavelengths result in the selective Raman enhancement of different polycyclic aromatic hydrocarbon ring systems.
Raman spectroscopy of a coal liquid shows that fluorescence interference is minimized with ultraviolet excitation.
The first ultraviolet resonance Raman measurements of a coal liquid are reported. The spectra detail the presence of numerous polycyclic aromatic hydrocarbons with ring systems similar to those of naphthalene, fluorene, phenanthrene, pyrene, and triphenylene . The ultraviolet resonance Raman measurements of this highly complex sample show no significant interference from fluorescence. The lack of fluorescence interference and the high selectivity indicate that ultraviolet resonance Raman spectroscopy is a powerful new technique for characterizing highly complex samples and mixtures.
Dating of Historical Manuscripts Using Spectrometric Methods: A Mini-Review
An overview is provided of spectrometric methods useful for age estimation of historical manuscripts (medieval ones in particular), in order to confirm their authenticity. Individual methods (infrared and Raman spectroscopy, mass spectrometry, atomic emission spectroscopy, X-ray spectroscopy, and electron scanning microscopy) are discussed and examples of their application described. The following general strategy can be recommended for dating and/or authenticating of historical manuscripts. First of all, the pigment analysis should be carried out using Raman spectroscopy (distinguishing the period and modern pigments), followed by PIXE ink analysis (solving the question of ink homogeneity). Finally, the radiocarbon dating of the writing support, potentially supplemented by the ink dating using scanning Auger microscopy should be performed.