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2000
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October
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In the Laboratory
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Determination of the Active Principle in a Syrup by Spectrophotometry and Principal Component Regression Analysis. An Advanced Undergraduate Experiment Involving Chemometrics
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María É. Ribone, Ariana P. Pagani, and Alejandro C. Olivieri
Departamento de Química Analítica, Facultad de Ciencias Bioquímicas y Farmacéuticas, Universidad Nacional de Rosario, Suipacha 531, Rosario 2000, Argentina
Héctor C. Goicoechea
Departamento de Química, Facultad de Bioquímica y Ciencias Biológicas, Universidad Nacional del Litoral, Paraje El Pozo, Santa Fe 3000, Argentina
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October 2000
Vol. 77 No. 10
p. 1330
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| Abstract |
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An advanced analytical chemistry laboratory experiment concerning the determination of the mucolitic bromhexine in a commercial syrup is described. It involves the following steps: (i) preparing nine calibration mixtures and recording their absorption spectra in the region 285-348 nm, (ii) recording spectrophotometric data for four synthetic unknowns and two commercial samples, and (iii) processing them with the multivariate calibration technique of principal component regression (PCR). The theory of PCR is discussed, and a Visual Basic 5.0 for Windows 95/98 program is made available to students for data processing. The program allows students to perform cross-validation and to obtain and save relevant statistical information (root mean square deviation, correlation coefficient, and relative error of prediction), as well as calibration spectral factors and spectral residuals for each test sample, all of which illustrate the PCR technique in detail. The reagents used are low-cost and nontoxic; the experiment is simple and gives students an insight into a real practice that integrates chemistry, instrumentation, and computer techniques.
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| Supplement |
Student lab documentation and a Visual Basic program are available as supplemental material. The program allows students to perform data processing, obtain and save statistical information, and produce several concentration and spectral plots that are relevant to principal component regression analysis.
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 Contents |
JCE2000p1330W.DOC (Microsoft Word 6.0, Windows), PROGRAM (folder of source files for Visual Basic program)
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| More Information |
Citation |
Ribone, María É.; Pagani, Ariana P.; Olivieri, Alejandro C.; Goicoechea, Héctor C. J. Chem. Educ. 2000 77 1330.
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Keywords |
Analytical Chemistry; Instrumental Methods; Laboratory Computing / Interfacing; Teaching / Learning Aids; UV-Vis Spectroscopy; Laboratory Instruction
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History |
Created:
Last Updated: |
September 22, 2000
August 31, 2005
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| Home > JCE Print > Journal of Chemical Education > Issues >
2000
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October
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1330
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