Daniel C. Harris

Quantitative Chemical Analysis Seventh Edition

Chapter 22 Mass spectrometry

Copyright © 2007 by W. H. Freeman and Company

What is mass 28?

•N2 •CO

•C2H4 (ethylene) •H6B2 (diborane)

http://webbook.nist.gov/chemistry/mw-ser.html

1 Instrumentation Instrumentation

2. Mass selection: 3 step program: • Magnetic sector • Quadrupole 1.Ionize • Time-of-flight (TOF) 2.Mass select • Ion trap 3.detect • Fourier transform ion cyclotron resonance • Ion Mobility

NB: REQUIRE VACUUM CHAMBER

Instrumentation – magnetic sector Instrumentation - quadrupole

2 Instrumentation - quadrupole Instrumentation - TOF

Instrumentation – ion trap Instrumentation – FT-ICR

3 Instrumentation – FT-ICR Instrumentation – ion mobility

Instrumentation – STEP 3: detector – STEP 1: Ion Source – Electron impact

Standard 70 eV electron impact ionization

http://webbook.nist.gov/chemistry/mw-ser.html

4 – STEP 1: Ion Source – STEP 1: Ion Source - MALDI How to make elephants fly

STEP 1: Ion Source - ESI STEP 1: Ion Source - ESI

5 1. Isotopes 3 ways to get more out of a mass spectrum: What does the mass spectrum of C look like?

1. Isotopes (quantitation) 2. Exact mass (resolution + accuracy) 3. Fragmentation (MS/MS)

1. Isotopes 1. Isotopes What does the mass spectrum of C look like? What does the mass spectrum of C look like?

What does the mass spectrum of C60 look like?

Elemental clues from isotope distributions

http://www2.sisweb.com/mstools/isotope.htm http://www2.sisweb.com/mstools/isotope.htm

6 1. Isotopes 1. Isotopes What does the mass spectrum of C look like? Chemical clues from isotope distributions

What does the mass spectrum of C60 look like? Water Elemental clues from isotope distributions

Chemical clues from isotope distributions

Kinetic isotope effect

1. Isotopes 1. Isotopes What does the mass spectrum of C look like? Chemical clues from isotope distributions

What does the mass spectrum of C60 look like?

Elemental clues from isotope distributions

Chemical clues from isotope distributions

Isotope mass spectrometry

7 1. Isotopes 2. Mass Accuracy

Isotope mass spectrometry Where do mass differences come from?

http://webbook.nist.gov/chemistry/mw-ser.html Mass resolution m/Δm

2. Mass Accuracy 3. Fragmentation

1. electron impact 2. CID – collision induced dissociation 3. Electron capture 4. BIRD 5.

Successive fragmentation: MS/MS/MS… http://webbook.nist.gov/chemistry/mw-ser.html

8 3. Fragmentation 3. Fragmentation EI

Standard 70 eV electron impact ionization

http://webbook.nist.gov/chemistry/mw-ser.html

3. Fragmentation

9 10