The Fluorescence of Lignum nephriticum: A Flash Back to the Past and a Simple Demonstration of Natural Substance Fluorescence

• Mark Muyskens ^[1]
  1. [1] Calvin College

     Calvin College

     City of Grand Rapids, Estados Unidos

     
• Localización: Journal of chemical education, ISSN 0021-9584, Vol. 83, Nº 5, 2006, pág. 765
• Idioma: inglés
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• Resumen

  • This article describes a simple but visually striking demonstration of fluorescence from the aqueous extract of the tropical hardwood Pterocarpus indicus. It illustrates the first recorded observation of fluorescence, noted over 400 years ago when the wood was known as Lignum nephriticum.The fact that the strong, blue fluorescence is dramatically pH dependent provides an interesting dimension to the demonstration. A yellow filter allows a simple demonstration of the Stokes shift. Highlighting the historical significance of Lignum nephriticum and discussing some of the relevant studies suggesting the chemical origin of the fluorescence provides a context for this demonstration.