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  Home > JCE Print > Journal of Chemical Education > Issues > 1997  > February  >
In the Laboratory
Screening and Sequential Experimentation: Simulations and Flame Atomic Absorption Spectrometry Experiments
Richard J. Stolzberg
Department of Chemistry and Biochemistry, University of Alaska Fairbanks, Fairbanks, AK 99775-6160

Cover
February 1997
Vol. 74 No. 2
p. 216

Abstract
Students are introduced to screening and sequential experimentation using simulations and experimentation. The work begins with spreadsheet simulations and practice with the experimental design software. Students learn how to use the graphical output, normal quantile plots, to recognize the specific factors that affect the result of an experiment. In the laboratory, students make a preliminary investigation of the effect of six variables (flame observation height, flame stoichiometry, acetic acid, lamp current, wavelength, and slit width) on the atomic absorption signal for silver. This requires only sixteen experiments. Two or three active variables and an interaction of two variables are typically observed. Following this 26-2 fractional factorial design experiment, students investigate the effect of two active variables in more detail. This typically requires 16 to 25 experiments. The complexity of the system becomes apparent when flame observation height and percentage of acetic acid are studied. Most, but not all, of the observations are consistent with descriptive material that would be found in a typical instrumental methods text.
More Information
*  Citation
Stolzberg, Richard. J. Chem. Educ. 1997 74 216.
*  Keywords
Analytical Chemistry, Atomic Absorption Spectrometry, Experimental Design, Instrumental Methods, Laboratory Instruction, Silver
*  History
Created:
Last Updated:
July 29, 1999
June 23, 2005
  Home > JCE Print > Journal of Chemical Education > Issues > 1997 > February > Page 216


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