4th Exam Molecular Mass Spectrometry

Question 1

is a powerful and sensitive analytical
technique that is used to:

➢ Determine the masses of atoms, isotopes, molecules, or molecular fragments
➢ Determine the elemental composition of molecules and complex mixtures
➢ Identify unknown compounds
➢ Quantify known materials
➢ Elucidate structural and chemical properties of molecules

Answer 1

Mass Spectrometry

Question 2

Mass Spectrometry is a powerful and sensitive analytical technique for detection of compounds can be accomplished with very small quantities, even with _____ g or _____ moles

Answer 2

10^-12g or ~10^-15 moles

Question 3

With Mass spectrometry compounds can be identified at very low concentrations in complex mixtures such as: ____ ppt

Answer 3

1ppt (parts per trillion, i.e., 1 in 1012)

Question 4

• an instrument that separates rapidly moving ions based upon their mass-to-charge (m/z) ratio

Answer 4

Mass Spectrometer

Question 5

instruments that allows the masses of individual atoms or molecules that have been converted to ions to be determined.

Answer 5

Mass Spectrometer

Question 6

Because the mass of an individual atom or molecule is so small, we use the units of ________ instead of the atomic mass units (amu) in mass spectrometry.

Answer 6

Daltons (Da)

Question 7

T or F

Mass spectrometers range in size from that of a microwave oven to large research instruments that dominate entire rooms.

Answer 7

True

Question 8

The mass spectrometer is an instrument that (4)

Answer 8

 produces ions,
 separates them according to their m/z values,
 detects the ions and
 plots the mass spectrum.

Question 9

T or F

Mass Spectrometers vary widely in size, resolution, flexibility, and cost. Their components, however, are similar.

Answer 9

True

Question 10

is a graph of ion intensity or relative abundance as a function of mass to charge ratio (m/z)

are usually depicted either as a simple histogram or as the exact graph of intensity versus m/z ratio

Answer 10

mass spectrum

Question 11

can provide the molecular mass and the structure of the compound being analyzed under appropriate conditions

Answer 11

Mass Spectrum

Question 12

MS Sources Atoms

Answer 12

ICP – Inductively-Coupled Plasma

Question 13

MS Sources Small Molecules

Answer 13

EI – Electron Ionization
CI – Chemical Ionization
FI – Field Ionization
APCI – Atmospheric Pressure Chemical Ionization
APPI – Atmospheric Pressure Photoionization

Question 14

MS Sources Large Molecules

Answer 14

FAB – Fast Atom Bombardment
MALDI – Matrix-Assisted Laser Desorption/Ionization
ESI – Electrospray Ionization