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2007
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In the Laboratory
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Paint Analysis Using Visible Reflectance Spectroscopy
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An Undergraduate Forensic Lab
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Erin M. Hoffman and Douglas J. Beussman
Department of Chemistry, St. Olaf College, Northfield, MN 55057
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November 2007
Vol. 84 No. 11
p. 1806
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| Abstract |
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The study of forensic science is found throughout undergraduate programs in growing numbers, both as stand-alone courses as well as specific examples within existing courses. Part of the driving force for this trend is the ability to apply common chemistry techniques to everyday situations, all couched in the context of a mystery that must be solved. The paint analysis lab is meant to allow students to determine if paint samples that may appear similar to the human eye are really the same or if they have measurable differences. The forensic aspect of the experiment lies in the application of spectroscopy to determine if the paint sample found at a crime scene is indistinguishable to paint found in a suspect's possession. Since observed colors are due to light reflected from a surface, reflectance spectroscopy is used to analyze the various paint samples. Samples containing various percentages of white and blue paints are analyzed using the 1976 CIELab color space system. As part of this experiment, students learn about reflectance spectroscopy, sampling techniques, basic statistics, and the fact that they can not always rely on initial observations.
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| Supplement |
Instructions for the students and notes for the instructor are available
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| More Information |
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Citation |
Hoffman, Erin M.; Beussman, Douglas J. J. Chem. Educ. 2007, 84, 1806.
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Keywords |
Analytical Chemistry; Dyes / Pigments; First-Year Undergraduate / General; Forensic Chemistry; Hands-On Learning / Manipulatives; Laboratory Instruction; Nonmajor Courses; Spectroscopy; Upper-Division Undergraduate; UV-Vis Spectroscopy
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History |
Created:
Last Updated: |
9/19/2007
9/27/2007
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 Caution! | | Experiments, laboratory exercises, lecture demonstrations, and other descriptions of the use of chemicals, apparatus, instruments, computers, and computer interfaces are presented in the Journal of Chemical Education as illustrative of new or improved ideas or concepts in chemistry instruction and are directed at qualified teachers. Although every effort is made to assure and encourage safe practices and safe use of chemicals, the Journal of Chemical Education cannot assume responsibility for uses made of its published materials. Many chemicals are hazardous. Precautions for the safe use of hazardous chemicals and directions for their proper disposal are described in the Material Safety Data Sheets and on the labels. We strongly urge all those planning to use materials from our pages to make choices and to develop procedures for laboratory and classroom safety in accordance with local needs and situations. |
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