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ERIC Number: EJ1003236
Record Type: Journal
Publication Date: 2012-Dec
Pages: 4
Abstractor: As Provided
Reference Count: 25
ISSN: ISSN-0021-9584
A Direct, Competitive Enzyme-Linked Immunosorbent Assay (ELISA) as a Quantitative Technique for Small Molecules
Powers, Jennifer L.; Rippe, Karen Duda; Imarhia, Kelly; Swift, Aileen; Scholten, Melanie; Islam, Naina
Journal of Chemical Education, v89 n12 p1587-1590 Dec 2012
ELISA (enzyme-linked immunosorbent assay) is a widely used technique with applications in disease diagnosis, detection of contaminated foods, and screening for drugs of abuse or environmental contaminants. However, published protocols with a focus on quantitative detection of small molecules designed for teaching laboratories are limited. A competitive, direct ELISA used to detect and quantify levels of digoxin, a cardiac glycoside, is described. Unique features of this lab include collecting data in quadruplicate followed by statistical analysis of replicates using a Q-test. Use of a microplate reader for measuring absorbances makes data collection extremely quick. Students plot their average absorbance versus log concentration digoxin and fit data to a third- or fourth-order polynomial. They also examine the maximum and minimum absorbance for the assay, determine the region of linearity, and then fit the linear region to a straight-line equation that can be used to determine the concentration of an unknown. The experiment can be completed in a 3-h period and is suitable for upper-level biochemistry, chemistry, and biology students. Although students find understanding a competitive ELISA more challenging than some other experiments, they enjoy learning about this commonly used laboratory technique. (Contains 1 table and 1 figure.)
Division of Chemical Education, Inc and ACS Publications Division of the American Chemical Society. 1155 Sixteenth Street NW, Washington, DC 20036. Tel: 800-227-5558; Tel: 202-872-4600; e-mail:; Web site:
Publication Type: Journal Articles; Reports - Research
Education Level: Higher Education
Audience: N/A
Language: English
Sponsor: N/A
Authoring Institution: N/A