MS_experiment - ethylbenzene tributylamine dibutyl ether...

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ORGANIC CHEMISTRY LANEY COLLEGE CHEM 12A Version 1.0, 11/12/07 Mass Spectrometry (MS). Identification of an Unknown Analgesic. Reading Technique 28 in Pavia; Wade, Section 12-13 to 12-15 Description You work for Crime Scene Investigator (CSI) – Laney. You and your partners have discovered a mysterious unknown substance that is believed to be a sample of one of the following analgesics – aspirin, acetaminophen, or methyl salicylate – or is possibly the central nervous system (CNS) stimulant, caffeine. As one of the routine analyses that you perform in the CSI-Laney laboratory, you are confident that identification using GC-MS is the quickest, failsafe method (aside from a simple melting point) to reveal the identity of the substance. Prelab Read through the sections above. The prelab exercise is to show the common potential fragmentations listed in the summary on p. 549 of Wade, as they apply to the following six compounds hexane, 2-pentanol,
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Unformatted text preview: ethylbenzene, tributylamine, dibutyl ether, and 2-nonanone (you may have look up the structures of these compounds) Procedure Your instructor will demonstrate how to run the instrument during laboratory. Choose one of the four solid unknowns A, B, C or D. Dissolve ~10 mg for solid samples (or 1 drop for a liquid sample) in 3 mL of dichloromethane (CH 2 Cl 2 ). Inject 1 µ L of this mixture into the GC-MS and determine the mass spectrum for the major peak found in the chromatogram. Plot the chromatogram and spectrum. To Complete the Experiment Determine the identity of the unknown compound. Report the masses (m/z values) of the molecular ion (if present), the base peak (with a suggested identity of the ion responsible for it), and the two next-most abundant ions....
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