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  Home > JCE Print > Journal of Chemical Education > Issues > 2005  > December  >
In the Laboratory
Determination of Hypochlorite in Bleaching Products with Flower Extracts To Demonstrate the Principles of Flow Injection Analysis
Luiz Antônio Ramos, Kátia Roberta Prieto, Éder Tadeu Gomes Cavalheiro, and Carla Cristina Schmitt Cavalheiro
Instituto de Química de São Carlos, Departamento de Química e Física Molecular, Universidade de São Paulo, 13566-950 São Carlos, SP Brazil
Cover
December 2005
Vol. 82 No. 12
p. 1815
Abstract
The use of crude flower extracts is proposed to teach the principles of flow injection procedures. In this experiment a bleaching reaction between hypochlorite and the anthocyanins contained in the flower extracts is examined. The bleaching of the crude extract solution was monitored at 526 nm in pH 2.0 buffer. A typical linear analytical curve was obtained over a hypochlorite concentration of 1.4 to 8.6 x 10-3 mol L-1 with a detection limit of 1.5 x 10-4 mol L-1. The relative standard deviation was 0.2% for a 2.5 x 10-2 mol L-1 hypochlorite solution (n = 10), and 80 determinations per hour were obtained. These parameters could be obtained by the students in a four-hour laboratory.
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JCE2005p1815W.pdf
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*  Citation
 Ramos, Luiz Antônio; Prieto, Kátia Roberta; Cavalheiro, Éder Tadeu Gomes; Cavalheiro, Carla Cristina Schmitt. J. Chem. Educ. 2005 82 1815.
*  Keywords
 Analytical Chemistry; Aromatic Compounds; Dyes / Pigments; First-Year Undergraduate / General; Hands-On Learning / Manipulatives; Laboratory Instruction; Natural Products; pH; Quantitative Analysis; Upper-Division Undergraduate; UV-Vis Spectroscopy
*  History
 Created:
Last Updated:		 October 25, 2005
November 4, 2005
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