L13_CHEM480_JCCYu - fragmentation than electron ionisation...

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1 Forensic Instrumental Analysis ± Forensic Instrumental Analysis focuses on solving forensic related problems and applying analytical procedures that are defendable in front of a court. ± Chromatography (separation science) and mass spectroscopy are two important parts of mass spectroscopy are two important parts of both Instrumental and Forensic Instrumental Analysis. Molecular Mass Spectrometry Daughter ions C 6 H 5 CH 2 CH 3 + e - C 6 H 5 CH 2 CH 3 + + 2e - M + e- Æ M .+ + 2e-
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2 Ion Sources Electron impact ion source Chemical Ionisation (CI) CH4 + e- Æ CH4+. , CH3+. , CH2+. CH4+. + CH4 Æ CH5+ + CH3. (reagent ion) The main reaction is the transfer of a proton to the sample: M + CH5+ Æ [M+H]+ + CH4 (100-200eV) Chemical ionisation yields less
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Unformatted text preview: fragmentation than electron ionisation Other reagent: ammonia and isobutane Hard ionization 1-decanol Soft ionization 3 McLafferty rearrangement Methylene chloride 1-pentanol Electron impact 4 MALDI-TOF, nicotinic acid matrix, 266-nm laser 5 ESI Common ESI Detection Positive Ion Negative Ion Amino Carboxylate Amide Hydroxyl/Phenol Ester Imide Aldehyde/Keto Hydroxyl 6 ESI - Positive Ion Detection Mode ESI for ATCA ESI Negative Ion Detection Mode A rotaxane is a mechanically-interlocked molecular architecture consisting of a "dumbbell shaped molecule" 7 DESI Desorption Electro Spray Ionization...
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This note was uploaded on 04/02/2009 for the course CHM 480 taught by Professor Yu during the Spring '09 term at Sam Houston State University.

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L13_CHEM480_JCCYu - fragmentation than electron ionisation...

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