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  Home > JCE Print > Journal of Chemical Education > Issues > 2002  > January  >
In the Laboratory
Advanced Chemistry Classroom and Laboratory
Microscale Determination of Vitamin C by Weight Titrimetry
Gaston A. East and Erica C. Nascimento
Instituto de Química, Universidade de Brasilia, Brasilia, DF, Brazil
Cover
January 2002
Vol. 79 No. 1
p. 100
Abstract
A laboratory experiment involving the quantitative microscale determination of ascorbic acid in pharmaceutical tablets of vitamin C by weight-titrimetry using (diacetoxyiodo)benzene as titrant and differential electrolytic potentiometry to locate the end-point is presented. The experiment affords an opportunity for students to explore nonconventional techniques such as the use of a novel organic oxidimetric titrant, titration in a semiaqueous medium, gravimetric titration, and an electrometric method of end-point detection using polarized electrodes. Synthesis, purification, and purity checking of the titrant may also be included in the project. Some advantages of the method are very low reagent consumption, low-cost equipment, improved sensitivity, and high precision and accuracy. Furthermore, the experiment will help the student to relate chemical analysis to everyday life.
Supplement
Detailed lab documentation and notes for instructors are available.
*  Contents JCE2002p0100W.doc (Microsoft Word)
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JCE2002p0100W.pdf

JCE2002p0100W.zip

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More Information
*  Citation
 East, Gaston A.; Nascimento, Erica C. J. Chem. Educ. 2002 79 100.
*  Keywords
 Analytical Chemistry; Electrochemistry; Instrumental Methods; Laboratory Instruction; Microscale; Quantitative Analysis; Vitamins
*  History
 Created:
Last Updated:		 December 3, 2001
March 16, 2005
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