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In the Laboratory
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FIA-Spectrophotometric Method for Determination of Nitrite in Meat Products: An Experiment Exploring Color Reduction of an Azo-Compound
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José C. Penteado, Lúcio Angnes, and Jorge C. Masini
Instituto de Química, Universidade de São Paulo, 05513-970 São Paulo, SP, Brazil
Paulo C. C. Oliveira
Departmento de Química, Universidade Federal de Alagoas–UFAL, Campus A. C. Simões, 57072-970 Maseió, AL, Brazil
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July 2005
Vol. 82 No. 7
p. 1074
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| Abstract |
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This article describes the reaction between nitrite and safranine O. This sensitive reaction is based on the disappearance of color of the reddish-orange azo dye, allowing the determination of nitrite at the mg mL–1 level. A factorial optimization of parameters was carried out and the method was applied for the quantification of nitrite in sausages. The proposed experiment is attractive for the students, since several important aspects are addressed. First of all, it is not typical to explore color disappearance, especially when a chromophore such as the azoic compound safranine O is used. The quantification of nitrite is made in real samples (sausages), which are more relevant than synthetic samples. In addition, the presence of nitrite in foods leads to discussions on the function of nitrite in foodstuff and its effect on human health. The assembling of the FIA system is instructive for the students and can provide an ideal time to discuss concepts as fluid hydrodynamics, reaction kinetics, spectrophotometry, and mixing processes.
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| Supplement |
Instructions and laboratory notes for students are available.
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 Contents |
JCE2005p1074W.doc (Microsoft Word)
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| More Information |
Citation |
Penteado, José C.; Angnes, Lúcio; Masini, Jorge C.; Oliveira, Paulo C. C. J. Chem. Educ. 2005 82 1074.
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Keywords |
Analytical Chemistry; Applications of Chemistry; Calibration; Chemoinformatics; Chemometrics; Food Science; Graduate Education / Research; Hands-On Learning / Manipulatives; Instrumental Methods; Kinetics; Laboratory Instruction; Quantitative Analysis; Upper-Division Undergraduate; UV-Vis Spectroscopy
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History |
Created:
Last Updated: |
May 31, 2005
June 8, 2005
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| Home > JCE Print > Journal of Chemical Education > Issues >
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1074
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