10/30/09 1 Lecture 20 – Oct 28 Chem 4101 – Fall 2009 Mass Spectrometry 1- Mass analyzers 2- Detectors 3- Applications -Sections 11B, 20C, 20D, 20E Suggested exercises: 20-8, 20-17, 20-18, 20-19 Lecture 20 – Oct 28 Chem 4101 – Fall 2009 Mass Spectrometer Components Figure 11-1, 20-11, Sections 11A, 20C Mass analyzers Time of flight (TOF) Quadrupole (Quad, Q) Sector Fourier transform (FT) Linear ion trap (LT) Orbitrap Lecture 20 – Oct 28 Chem 4101 – Fall 2009 Mass Analyzer- Time of Flight Figure 20-15, 11-10 Section 20B, 11B10/30/09 2 Lecture 20 – Oct 28 Chem 4101 – Fall 2009 Time of Flight Ion energy grid Voltage = V 103 ~104 V Field free separation region (time of fly tube) Length = L ~1m Eq. 20-10 Lecture 20 – Oct 28 Chem 4101 – Fall 2009 TOF Analyzer: Advantages and Disadvantages Advantages: 1 Simplicity 2 Ruggedness 3 Accessibility of the ion source 4 Unlimited mass range Disadvantages: 1 Resolution 2 Sensitivity Lecture 20 – Oct 28 Chem 4101 – Fall 2009 Mass Analyzer- Quadrupole Figure 11-6, Section 11B10/30/09 3 Lecture 20 – Oct 28 Chem 4101 – Fall 2009 x z + + Operation of a Quadrupole in the xz Plane Figure 11-7 + Lecture 20 – Oct 28 Chem 4101 – Fall 2009 Only AC Voltage Figure 11-8a Section 11B Lecture 20 – Oct 28 Chem 4101 – Fall 2009 Only DC voltage Figure 11-8b Section 11B10/30/09 4 Lecture 20 – Oct 28 Chem 4101 – Fall 2009 Figure 11-8c Section 11B A Combination of AC and DC Voltages Lecture 20 – Oct 28 Chem 4101 – Fall 2009 m/z transmitted at different quadrupole potentials Figure 11-9, Section 11B Lecture 20 – Oct 28 Chem 4101 – Fall 2009 Q Analyzer: Advantages and Disadvantages Advantages: 1 High sample throughput 2 Fast scan rate Disadvantages: 1 Resolution limited 2 m/z range limited (100~4000)10/30/09 5 Lecture 20 – Oct 28 Chem 4101 – Fall 2009 Tandem MS (MS/MS) Figure 20-21, Section 20C Lecture 20 – Oct 28 Chem 4101 – Fall 2009 Tandem MS of precursor ion 279 m/z Figure 20-22, Section 20C What fragments correspond to the detected ions? Lecture 20 – Oct 28 Chem 4101 – Fall 2009 Dissociative Interactions in the Interaction Cell 1 Collision induced dissociation (CID) 2 Surface-induced dissociation (SID) 3 Electron-capture dissociation (ECD) 4 Photo-induced dissociation (PID)10/30/09 6 Lecture 20 – Oct 28 Chem 4101 – Fall 2009 Tandem Mass Spectrometry www.chem.agilent.com/en-US/Products/Instruments/ms/6410triplequadrupolelcms/pages/gp56595.aspx Figure 20-23, Sections 20B Lecture 20 – Oct 28 Chem 4101 – Fall 2009 Detectors – electron multipliers www.sge.com, www.eaglabs.com Section 11B-1 Gain: 107 Gain: 105 108 Lecture 20 – Oct 28 Chem 4101 – Fall 2009 Applications Section 20C10/30/09 7 Lecture 20 – Oct 28 Chem 4101 – Fall 2009 Summary 1 How does a TOF analyzer work? 2 How does a quadruple analyzer work? 3 What is a precursor ion? Product ion? 4 Why do we need tandem mass spectrometry? Lecture 20 – Oct 28 Chem 4101 – Fall
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