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Quantitative Assay for Starch by Colorimetry Using a Desktop Scanner

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Kurt R. Mathews , James D. Landmark and Douglas F. Stickle

Department of Pathology and Microbiology, University of Nebraska Medical Center, Omaha, NE 68198-3135

J. Chem. Educ., 2004, 81 (5), p 702

DOI: 10.1021/ed081p702

Publication Date (Web): May 1, 2004

Section:

History, Education, and Documentation

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.

Keywords (Audience):

High School / Introductory Chemistry

Keywords (Domain):

Analytical Chemistry

Keywords (Pedagogy):

Hands-On Learning / Manipulatives

Keywords (Subject):

Separation Science

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Citing Articles

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This article has been cited by 2 ACS Journal articles (2 most recent appear below).

Kinetic Analysis of Amylase Using Quantitative Benedict's and Iodine Starch Reagents
Beverly Cochran , Deborah Lunday and Frank Miskevich
Journal of Chemical Education2008 85 (3), 401
- Kinetic Analysis of Amylase Using Quantitative Benedict's and Iodine Starch Reagents
  Beverly Cochran , Deborah Lunday and Frank Miskevich
  Journal of Chemical Education2008 85 (3), 401
  Quantitative analysis of carbohydrates is a fundamental analytical tool used in many aspects of biology and chemistry. We have adapted a technique developed by Mathews et al. using an inexpensive scanner and open-source image analysis software to quantify ...
  Abstract | Hi-Res PDF | PDF w/ Links
Demonstration of Absorbance Using Digital Color Image Analysis and Colored Solutions
Shane K. Kohl , James D. Landmark and Douglas F. Stickle
Journal of Chemical Education2006 83 (4), 644
- Demonstration of Absorbance Using Digital Color Image Analysis and Colored Solutions
  Shane K. Kohl , James D. Landmark and Douglas F. Stickle
  Journal of Chemical Education2006 83 (4), 644
  This article describes a simple experiment in which the principle of absorbance may be demonstrated using digital color image analysis. Dilute yellow food coloring solutions in water were prepared in known relative concentrations and photographed in ...
  Abstract | Hi-Res PDF | PDF w/ Links