Kinetics-Based Indirect Spectrophotometric Method for Simultaneous Determination of MnO4 (-) and Cr207 (2-): A Modern Instrumental Analysis Laboratory Experiment Page: 3 of 3
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As part of the laboratory instruction, students in our
instrumental analysis course are given the analytical results
(CCr2o, and CMnO4 values) for their unknown sample, which
were determined using the more conventional two-wavelength
spectrophotometric method (see eqs 3 and 4) by undergraduate
students enrolled in the preceding semester's quantitative
analysis course. They are asked to statistically analyze data
from the kinetics-based and two-wavelength methods and to
determine if there is a significant difference between the two
methods. The statistical treatment is discussed in most standard
analytical textbooks (19-2). Rarely are undergraduate students
afforded the opportunity to actually apply the treatment to
their experimental data. Such analysis leads into a discussion of
factors that are considered in selecting an analytical method.
Selection of an appropriate analytical method is a decision that
practicing analytical chemists encounter daily.
From an educational standpoint, we prefer the kinetics-
based experiment to the more traditional two-component,
two-wavelength spectrophotometric methods published in
standard laboratory manuals. The experiment not only in-
corporates the important fundamental principles associated
with spectroscopic analysis, but it also exposes students to
kinetics-based techniques, which are often encountered in
enzyme and drug determinations. Moreover, the kinetics-
based method presented above provides students who have
already performed a two-component spectroscopic analysis
based upon eq 2 in their quantitative analysis course a suitable
alternative laboratory experiment. If desired, the experiment
can be shortened so as to analyze only one of the two ions.
Acknowledgment
Sandra Padilla, Ashante Trufant, Noe De La Sancha, and
Ernesto Vela thank the U.S. Department of Education for
support provided to them under the Upward Bound Math
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Pandey, Siddharth; McHale, Mary E. R.; Horton, Ann-Sofi M.; Padilla, Sandra A.; Trufant, Ashantè L.; De La Sancha, Noé U. et al. Kinetics-Based Indirect Spectrophotometric Method for Simultaneous Determination of MnO4 (-) and Cr207 (2-): A Modern Instrumental Analysis Laboratory Experiment, article, April 1, 1998; [Washington, D.C.]. (https://digital.library.unt.edu/ark:/67531/metadc674087/m1/3/: accessed April 17, 2024), University of North Texas Libraries, UNT Digital Library, https://digital.library.unt.edu; crediting UNT College of Arts and Sciences.