The use of microspectrofluorimetry for the characterization of lake pigments

Maria J. Melo, Stephan Schäfer, J. Sérgio Seixas de Melo, Fernando Pina, Klaas Jan van den Berg, Aviva Burnstock

Research output: Contribution to journalArticlepeer-review

75 Citations (Scopus)

Abstract

In this paper, the potential of confocal microfluorescence spectroscopy is explored for the characterization of selected red lake pigments and paints based on alizarin, purpurin and eosin (weak, medium and strong emitters). The anthraquinone pigments have been used since ancient times by artists, and eosin lakes were used by impressionist painters. Reconstructions of artists paints based on 19th century recipes are examined. The paints were made using the lake pigments bound in a range of binding media including gum arabic, collagen, a vinyl emulsion and linseed oil. The acquisition of the spectra is rapid, with high spatial resolution and the data reliable and reproducible. Together with full emission spectra, it was possible to acquire well-resolved excitation spectra for purpurin, alizarin and eosin based colors. The present investigation suggests that micro-emission fluorescence can also be used as a semi-quantitative method for madder lake pigments, enabling the determination of purpurin lake ratio in a mixture of purpurin and alizarin, which is important for provenance studies. The data obtained with microfluorescence emission with those acquired with fiber-optic fluorimetry are compared. The spatial resolution used, 8 μm, is appropriate for the analysis of individual pigments particles or aggregates in a paint film. Micro-emission molecular fluorescence proved to be a promising analytical tool to identify the presence of selected red lake pigments combined with a range of binding media.

Original languageEnglish
Pages (from-to)922-929
Number of pages8
JournalTalanta
Volume74
Issue number4
DOIs
Publication statusPublished - 15 Jan 2008

Keywords

  • In situ dye analysis
  • Microfluorescence spectroscopy
  • Red lake pigments

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