Ch11 - Chapter 11 Atomic Mass Spectrometry Announcements...

Info iconThis preview shows pages 1–11. Sign up to view the full content.

View Full Document Right Arrow Icon
Chapter 11 Atomic Mass Spectrometry Announcements 1.Your term tests will be returned on Thursday, along with lab reports 2.An answer key to the term test will be posted outside Dr. K’s office.
Background image of page 1

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Steps involved
Background image of page 2
The ‘Dalton’ (Da) is the same as the ‘Atomic Mass Unit’ C mol C atoms x C mol C g C atom of mass 12 6 12 6 23 12 6 12 6 12 6 10 022142 . 6 12 1 = C atom g x 12 6 23 10 992646 . 1 = - Da amu = 1 1 Da g x g x = = = - - 1 10 6605387 . 1 ) 10 992646 . 1 ( 12 1 24 23 Da = amu = 1/12 the mass of one C-12 atom
Background image of page 3

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
Schematic Diagram of Mass Spectrometer Mass analyzers work on physical principles. Ions are manipulated in a combination of electric and/or magnetic fields. Neutral atoms or molecules won’t behave the right way.
Background image of page 4
In the plasma : Processes associated with atomization
Background image of page 5

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
There’s a strong analogy between a mass spectrometer and an emission spectrometer ‘Sorting’ of wavelengths ‘Sorting’ of ions by mass
Background image of page 6
Types of Mass Analyzers 1. Quadrupole (mass filter) 2. Single sector magnetic analyzer 3. Double focusing mass analyzer
Background image of page 7

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
The Quadrupole Mass Filter The ‘poles’ are electrodes, that have both DC and AC (RF) voltages applied to them. Ions either make it through the filter (stable) or they do not
Background image of page 8
Configuration of Voltages Each pair of opposing rods is connected; the opposing rods have exactly the same voltage. The rods have superimposed DC and AC (RF) voltages. Two rods have a voltage =+[V DC +V RF cos( ϖ t)] Other rods have voltage =- [V DC +V RF cos( ϖ t)] Only ions of a specific mass/charge ratio make it down through the center of the rods based on the ratio of the DC and RF voltages. The magnitudes of V and V are varied in time.
Background image of page 9

Info iconThis preview has intentionally blurred sections. Sign up to view the full version.

View Full DocumentRight Arrow Icon
- y Effect of fields on ion trajectories If there was only a DC component to fields, no ions could make it through. Positively charged ions
Background image of page 10
Image of page 11
This is the end of the preview. Sign up to access the rest of the document.

Page1 / 35

Ch11 - Chapter 11 Atomic Mass Spectrometry Announcements...

This preview shows document pages 1 - 11. Sign up to view the full document.

View Full Document Right Arrow Icon
Ask a homework question - tutors are online