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| Home > JCE Print > Journal of Chemical Education > Issues >
2007
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In the Classroom
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A Method for Analyzing A + 2 Isotope Patterns for Use in Undergraduate Organic Courses
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Ray A. Gross, Jr.
Department of Physical Sciences and Engineering, Prince George's Community College, Largo, MD 20774
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June 2007
Vol. 84 No. 6
p. 987
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| Abstract |
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A new method for analyzing the characteristic molecular-ion peak intensities found in the low-resolution mass spectra of compounds that contain small numbers of bromine, chlorine, and sulfur atoms has been developed. The method determines the subscripts of Br, Cl, and S in the molecular formulas of compounds that contain these atoms. The method depends on the intensity of each significant molecular-ion peak falling within a predictable range of values relative to the intensity of the parent peak. The use of a range of values sets this method apart from earlier methods. This method has a ninety-eight percent accuracy record for the determination of 21 different combinations of Br, Cl, and S atoms when the intensity of the parent peak is more than 3.5%. The intensity ratios for these 21 combinations were placed on a spreadsheet, producing an isotope-pattern analyzer designed specifically for use in organic qualitative analysis at the undergraduate level. The method affords students and instructors a useful tool for rapidly assessing the Br, Cl, S stoichiometry of an unknown from its mass spectrum.
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| Supplement |
Appendix I, Intensity Ratios for Compounds Containing Bromine, Chlorine, and Sulfur; Appendix II, Isotope-Pattern Analyzer (IPA); Appendix III, Example Problems with Answers; Appendix IV, IPA Results are available.
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| More Information |
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Citation |
Gross, Ray A., Jr. J. Chem. Educ. 2007, 84, 987.
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Keywords |
Bromine; Chlorine; Computer-Based Learning; Isotopes; Mass Spectrometry; Molecular Properties / Structure; Organic Chemistry; Problem Solving / Decision Making; Qualitative Analysis; Sulfur; Upper-Division Undergraduate
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History |
Created:
Last Updated: |
4/24/2007
5/3/2007
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| Home > JCE Print > Journal of Chemical Education > Issues >
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June
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