JCE Online Journal of Chemical Education
 | Subscriptions  | Software Orders  | Support  | Contributors  | Advertisers  | 

JCE Print
   Current Issue
 Previous Issues
 Supplements
 Search JCE Index

JCE Digital Library
   DigiDemos
 QBank
 SymMath
 WebWare

JCE Software
   Latest Releases
 Software & Video
 Downloads
 Support

Only@JCE Online
   JCE Online Store
 JCE HS CLIC
 JCE Discussion Forums
   Biographical Snapshots
 ChemEd Resource Shelf
 Featured Molecules
 Hal's Picks
 Project Chemlab
 Reviewed WWW Sites
 "Web-Ed" Articles

About JCE
   Features
 Publications
 Operations
 Outreach
 Contact Us


  Home > JCE Print > Journal of Chemical Education > Issues > 2004  > May  >
In the Laboratory
Quantitative Assay for Starch by Colorimetry Using a Desktop Scanner
Kurt R. Mathews, James D. Landmark, and Douglas F. Stickle
Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198-3135
Cover
May 2004
Vol. 81 No. 5
p. 702
Abstract
Solution color change by mixture of iodine with starch is well-known. Here we describe a procedure to produce a standard curve for quantification of starch concentration using colorimetry. The colorimetry is performed by image analysis of a picture of solutions obtained using a desktop scanner. The analysis is performed using a Visual Basic computer program (COLORS.EXE) that measures red, green, and blue pixel intensities from the image. The computer program is provided in Supplemental Material in JCE Online. The lower limit of detection of the described assay is of the order of 10 mg/dL. The measurement of the starch content in potatoes is given as an example. The experiment can serve as an introduction to quantitative analytical chemistry at the high school level and has the desirable feature of using only common and inexpensive reagents. The procedure is likely amenable to further development for other food science experiments.
Supplement
Notes for the instructor, a color image of the microtitre plate containing the stock solutions, and a Visual Basic computer program (colors.exe) for RGB data analysis from a computer image file are available.
*  Contents Folder JCE2004p0702W containing colors.exe and plate.jpg.
*  Download
JCE2004p0702W.pdf

JCE2004p0702W.zip

JCE2004p0702W.sit
More Information
*  Citation
 Mathews, Kurt R.; Landmark, James D.; Stickle, Douglas F. J. Chem. Educ. 2004 81 702.
*  Keywords
 Analytical Chemistry; Carbohydrates; Food Science; General Chemistry; Introductory / High School Chemistry; Laboratory Computing / Interfacing; Laboratory Instruction; Natural Products; UV-Vis Spectroscopy
*  History
 Created:
Last Updated:		 April 1, 2004
February 18, 2005
<< Previous Article Table of Contents Next Article >>
  Home > JCE Print > Journal of Chemical Education > Issues > 2004  > May  > Page 702


Subscriptions
 Subscription Info
 Order Forms

JCE HS CLIC

Our Secondary School editors work hard to distill all the JCE materials to produce a fraction of particular interest to high school teachers. We call it CLIC.
 JCE HS CLIC

Contributions Welcome
JCE welcomes your submission
 Contributors' Corner

Advertisers
In recent years we have worked hard to better match our advertisers with our readers. When shopping for chemistry education materials, visit our advertisers' WWW sites first.
 Recent Advertisers

Be An Ambassador
Take JCE along on your outreach missions. Copies of the Journal, guest access to JCE Online, our publications catalog, and more are available for your participants.
 Outreach with JCE

Comments to
jceonline@chem.wisc.edu		 Copyright © Division of Chemical Education, Inc., American Chemical Society.
All rights reserved.