Term Test 2

Question 1

Separate ions from neutral atoms, sort ion bound on m/z ratio and count how many ions hit the detector

Answer 1

ICP-MS

Question 2

Advantages of ICP-MS

Answer 2

-Low detection limits (ppt)
-Large linear working range
-High productivity (multi-element, fast)
Isotope composition, not just concentration
-Can detect basically the entire Periodic table

Question 3

Breaks liquid into small droplets/fine mist

Answer 3

Nebulizer

Question 4

Remove large droplets so only fine droplets enter torch

Answer 4

Spray Chamber

Question 5

Ar plasma created by interaction between Ar and energy from RF coil

Answer 5

Torch

Question 6

Ion beam moving from a region of atm P (and high T) to very low vacuum

Answer 6

The Interface Region

Question 7

Allow for transmission of ion beam while simultaneously reducing pressure

Answer 7

Cones

Question 8

Clean up ion beam, separates ions from neutral species and photons

Answer 8

Ion Deflection Device

Question 9

Four rods are tuned so ions are deflected at a 90 degree angle and photons and neutrals pass straight through

Answer 9

Quadrupole Ion Deflector

Question 10

Caused when ions from the plasma or the sample (or combination of these) carry a m/z that is identical to that of the analyte ion

Answer 10

Spectral interferences

Question 11

Four classes of spectral interference in ICP-MS

Answer 11

Polyatomic/molecular, Oxides/hydroxides/hydrides, Doubly charged, Isobaric (isotopes with the same m/z)

Question 12

Most common type of spectral interference encountered

Answer 12

Polyatomic/Molecular Spectral Interference

Question 13

Produced by elements in the sample combining with H, O, or OH to form molecular hydride (H), oxide (O), and hydroxide (OH) ions. These interferences occur at 1, 16 and 17 mass units higher than the original element mass. Typically produced in the cooler zones of the plasma, immediately before the interface region

Answer 13

Oxides/Hydroxides/Hydrides

Question 14

Species formed when an ion is generated with a double positive charge. Produce a peak at half its mass

Answer 14

Double Charge Interferences

Question 15

Produced when different isotopes of other elements have the same m/z as the analyte

Answer 15

Isobaric Interferences

Question 16

This reduces spectral interferents but also reduces analyte signal

Answer 16

Collision Cell

Question 17

True or False? large species = more collisions = more KE at end of cell

Answer 17

False

*less KE at end of cell

Question 18

Reduces background while preserving analyte signal

Answer 18

Reaction Cell

Question 19

Convert beam of ions into an electrical signal that can be processed

Answer 19

Transducer

Question 20

The study of the radiation emitted when these excited electrons return to the ground state

Answer 20

Atomic Emission

Question 21

Function of Excitation source

Answer 21

• Convert sample into a cloud of atoms (atomization)

- Excite electrons in the atoms to higher electronic energy levels

Question 22

Sources of Excitation

Answer 22

1. Flame (flame photometry)
2. Plasma (inductively coupled plasma or ICP)
3. Electric arc/electric spark

Question 23

Emission separated into its constituent wavelengths

Answer 23

Wavelength Selector

Question 24

Electrically conducting gaseous mixture containing a significant concentration of cations and electrons, like gas but ions + electrons

Answer 24

Plasma

Question 25

Quartz torch surrounded by induction coil

Answer 25

Inductively Coupled Plasma Torch