Robert Q. Thompson,
Professor, at Oberlin since 1982

Research Interests:
capsaicinoids in chili peppers, liquid chromatography, solid phase extraction.      

6-ene-8-methyl capsaicin

Capsaicinoids, N-vanillyl acyl amides, are the "hot" components of chili peppers (genus Capsicum), many spicy foods, some topical pain-relief creams, and most defense sprays.  More than twenty naturally-occurring capsaicinoids are known with small, but significant differences in structure.   

The Thompson research group is interested in the separation and isolation of these capsaicinoids.  A variety of techniques are used in reaching this goal:  solid phase extraction, argentation chromatography, liquid chromatography - mass spectrometry, preparative chromatography, and nuclear magnetic resonance spectrometry.  Current work is focused on the isolation of the isomers of homodihydrocapsaicin and understanding the nature of the silver-capsaicinoid interaction.

The research group also is addressing the need for a colorimeteric test for the amount of capsaicinoids in chili pepper fruit.  A simple and quick test would provide chili pepper growers important feedback as they breed both hotter and milder chilis.  Several candidate color-forming reactions are being studied and assessed in terms of sensitivity, robustness, ease of use, and cost.

Teaches:
Analytical Chem, General Chem, Chem & Crime

Contact Information:
PH: 440 775 8305  
FAX: 440 775 6682 
robert.q.thompson@oberlin.edu  
Science Center Office: N372

Feature Article: Chemistry Lab Murder Trial

BA College of Wooster
PhD Michigan State

Recent sabbaticals
FBI Research Lab (1997) NIST (2003-04)

Representative Works:

• R.Q. Thompson, K.W. Phinney, L.C. Sander, M.J. Welch, "Reversed-phase Liquid Chromatography and Argentation Chromatography of the Minor Capsaicinoids", Anal. Bional. Chem., 2005, 381, 1432-1440.
• R.Q. Thompson, Forensic Chemistry Laboratory Manual, Analytical Sciences Digital Library, 2004, ASDL Entry 10002; 19/1/2004
• R.Q. Thompson, M.J. Pennino, M.J. Brenner, M.A. Mehta, :Isolation of Individual Capsaicinoids from Mixture and Their Characterization by ¹³ C NMR Spectrometry," Talanta, 2006, 70, 315-322