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Mass Spectrometry Week 2 Lab S117 Fall 2011 Overview • Post-Lab: Percent Alcohol in Wine – TurnItIn.com – Working with data sets – Analyzing data sets – Analysis of experimental procedure • Pre-lab: Mass Spectrometry – Fragmentation – Protein Analysis • Practical matters of lab meeting Assignments • Sign up for turnitin.com • Formal reports due electronically up to time of lab • One minute24 hours late = 20pt penalty • Give copy of lab notebook to AI in lab Excel • Working with data sets • Statistical Analysis • Certainty and uncertainty – Measurements – Experimental limit – Reproducibility Experimental Design • Practical Weaknesses? • Propagation of Error • Was the distillation useful? Pre-Lab: Mass Spectrometry Analysis of isotopes! Inlet System Ion Source Mass Analyzer Vacuum (10-5 10-8 torr) r Detector Nominal Mass and Exact Mass • Nominal Mass: Low resolution – – – 35Cl = 35 Da 37Cl = 37 Da CO = N2 = 28 Da • Exact Mass: High Resolution – – CO = 27.9949 Da N2 = 28.0061 Da Analysis of Molecules • Parent peak (molecular ion)and fragment peaks • Analysis of fragment patterns useful • Application to Cl2 isovaleraldehyde caffeine Analysis of Biomolecules • Complex molecules • Molecular mass in kiloDaltons (kDa) • Nobel Prizes for MS of proteins Proteins Made of Amino Acids Mass Spec and Mutations • Sickle Cell Anemia • Point Mutation • How can MS be used to identify Mutations? Identification of Proteins • Comparison of 2D electrophoresis Identification of Proteins Purified Protein Trypsin Digest Mix of Peptides Example 1 ASRLVMKQQKD Example 2 ASRLVKMQKQD ASR LVMK QQK D Mass Spec Mass Data of mixture MS Library Identity of Protein Practical Matters • • • • Meet in chemistry computer lab 006 Mass Spec lab tours Dry lab: No special clothing requirements! Remember formal report and lab notebook