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  Home > JCE Print > Journal of Chemical Education > Issues > 2006  > May  >
In the Classroom
JCE DigiDemos: Tested Demonstrations
The Fluorescence of Lignum nephriticum: A Flash Back to the Past and a Simple Demonstration of Natural Substance Fluorescence
Mark Muyskens
Department of Chemistry and Biochemistry, Calvin College, Grand Rapids, MI 49546-4403

checked by: Ed Vitz
Department of Chemistry, Kutztown University, Kutztown, PA 19530

Cover
May 2006
Vol. 83 No. 5
p. 765

Abstract
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. A companion JCE Classroom Activity provides a hands-on activity illustrating the fluorescence.

Featured on the cover.

Supplement
A photo of narra wood and information on wood sources, ultraviolet LEDs, and additional spectral data of narra solutions are available.
*  Contents JCE2006p0765W.doc (Microsoft Word)
*  Download
JCE2006p0765W.pdf

JCE2006p0765W.zip

More Information
*  Citation
Muyskens, Mark. J. Chem. Educ. 2006 83 765.
*  Keywords
Acids / Bases; Analytical Chemistry; Demonstrations; Elementary / Middle School Science; First-Year Undergraduate / General; Fluorescence Spectroscopy; Hands-On Learning / Manipulatives; High School / Introductory Chemistry; Natural Products; pH; Physical Chemistry; Public Understanding / Outreach; Second-Year Undergraduate; Solutions / Solvents; Upper-Division Undergraduate; UV-Vis Spectroscopy
*  History
Created:
Last Updated:
3/16/2006
3/31/2006
  Home > JCE Print > Journal of Chemical Education > Issues > 2006  > May  > Page 765


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