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Flashcards in Exam 1 Deck (20):
1

3 ionization methods

1. gas-phase
2. desorption
3. evaporative

2

Electron Impact

-gas-phase ionization method
-M+ ion formed
-Advantages: Data base searchable, structural information
-Disadvantages:
M+ occasionally absent

3

Chemical Ionization

-gas-phase ionization method
-M+1, M+18 formed
-Advantage: M+ usually present
-Disadvantage: Little structural information

4

Field Desorption

-Desorption Ionization method
-M+ formed
-Advantage: Nonvolatile compounds
-Disadvantage: Need specialized equipment

5

Fast Atom Bombardment

-Desorption ionization method
-M+1, M+ matrix, M+ cation formed
-Advantage: Nonvolatile Compounds, sequencing information
Disadvantage: Matrix interference, difficult to interpret

6

Plasma Desorption

-desorption ionization method
-M+
-Advantages: Nonvolatile Compounds
-Disadvantages: Matrix interference

7

Laser Desorption

-Desorption method
-M+1, M+ matrix
-Advantages: Nonvolatile compounds, bursts of ions
-Disadvantages: matrix interference

8

Thermospray

-Evaporative method
-M+
-Advantages: Nonvolatile compounds
-Disadvantages: Outdated

9

Electrospray

-Evaporative method
-M+, M++, M+++
-Advantages: Nonvolatile compounds interfaces with LC, forms multiply charged ions
-Disadvantages: limited classes of compounds, little structural information

10

5 types of mass analyzers

1. Magnetic Sector
2. quadrupole
3. ion trap
4. time of flight
5. fourier transformation

11

Magnetic Sector

-Mass Range: 1-15000 m/z
-Resolution: 0.0001
-Sensitivity: Low
-Advantage: High resolution
-Disadvantage: Low sensitivity, very expensive, high technical expertise

12

Quadrupole

-Mass range: 1-5000 m/z
-Resolution: Unit
-Sensitivity: High
-Advantages: easy to use, inexpensive, high sensitivity
-Disadvantages: Low resolution, low mass range

13

Ion trap

-Mass Range: 1-5000 m/z
-Resolution: Unit
-Sensitivity: High
-Advantages: easy to use, inexpensive, high sensitivity, Tandem (MS)
-Disadvantages: low resolution, low mass range

14

Time of Flight

-mass range: unlimited
-resolution: 0.0001
-sensitivity: high
-advantages: high mass range, simple design
-Disadvantage: very high resolution

15

Fourier Transform

-mass range: up to 70 kDa
-resolution: 0.0001
-sensitivity: high
-advantage: very high resolution and mass range
-disadvantage: very expensive, high technical expertise

16

5 common features of mass spectrometer

1. Computer System
2, Sample Introduction
3. Ionization Method
4. ion separation method
5. detector

17

How does hydrogen bonding affect infrared spectroscopy

Alters the stretching and bending vibrations

18

2 Types of IR

-Dispersion IR
-Fourier Transform

19

Important factors to consider when preparing an IR sample

-liquid can be neat or in solution
-solutions handled in cells of 0.1-1 mm thickness
-solvent must be dry and transparent in region of interest
-solids can be examined as mull, pressed disk, glassy film, or as powders

20

requirements for data to consider before interpreting IR

1. spectrum must be adequately resolved and of adequate intensity
2. spectrum should be of reasonably pure compound
3. spectrometer should be calibrated so bands are observed at proper frequencies or wavelengths
4. method of sample handling must be specified