Chromatography And Mass Spectrometry

Question 1

Refers to the group of techniques used to separate complex mixtures on the basis of different physical interactions between the individual compounds and the stationary phase of the system

Answer 1

Chromatography

Question 2

Basic components in any chromatographic technique

Answer 2

Mobile phase (gas or liquid; carries sample)
Stationary phase (solid or liquid; where mobile phase flows)
Column holding the stationary phase
Eluate

Question 3

What is measured in simple chromatography?

***

Answer 3

Distances of the separated components are compared relative to the baseline or origin set from the start

Question 4

SP and MP in simple chromatography

Answer 4

SP: paper
MP: solvent

Question 5

The farthest point the solvent reached

Answer 5

Solvent front

Question 6

A ratio of the distance travelled by the component to the distance travelled by the solvent

Answer 6

Retention factor (distance of component/distance of solvent)

Question 7

Relationship of rf and solubility

Answer 7

Directly proportional

Question 8

What is implied when rf value= 1

Answer 8

The solute has no affinity for the stationary phase and travels with the solvent front

Question 9

Types of chromatography

Answer 9

Paper
Thin layer
Gas
Etc

Question 10

It is a variant of column chrom and almost same as paper but glass coated by thin layer of film (alumina, paper, silica gel, cellulose) is used as sorbent and positioned at an angle

Answer 10

Thin layer

Question 11

Gas chrom is used to separate what?

Answer 11

Mixtures of compounds that are volatile or can be made volatile

Question 12

Applications of gas chromatography

Answer 12

Analysis of neutral and acidic drugs
Urine toxicological tests
Identify various types of alcohols

Question 13

Process of gas chrom

Answer 13

→ Solution is vaporized, transferred to column of gas
→ Compounds separate according to volatility and polarity
→ Gas passes through a detector where it is identified
→ Chromatogram is generated (based on detector intensity over time)

Question 14

Retention time in gas chrom is based on

Answer 14

Analytes that elute

Question 15

Gases often used in gas liquid chrom

Answer 15

Helium, nitrogen or hydrogen

Question 16

T or F: gases of higher weights are nearer to the detector within the column and moving more rapidly while lower weights are closer to the sample injector

Answer 16

False, high-sample injector, low- detector in column, moves rapidly

Question 17

Compounds with _____ boiling point will move slowly in gas chrom

Answer 17

Higher

Question 18

Molecules which are more abundant in stationary or liquid phase (less volatile) will be ______________, those with more abundance in the gas phase (more volatile) will be ______________

Answer 18

Molecules which are more abundant in STATIONARY OR LIQUID phase (LESS VOLATILE) will be nearer to the sample injector, those with more abundance in the GAS phase (more volatile) will be further into the column

Question 19

An analytical technique that ionizes chemical species and sorts the ions based on their mass-to-charge ratio

Answer 19

Mass spectrometry

Question 20

How are the said chemical species ionized?

Answer 20

• Ionization is changed by removing or charging electrons in a chemical species

Question 21

Differentiate mass spectrum and mass spectrometer

Answer 21

A mass spectrum measures the masses within a sample; A mass spectrometer produces charged particles (ion) from the chemical substances that are to be analyzed, which then uses electric and magnetic fields to measure the mass (‘weight’) of the charged particles

Question 22

Atoms of the same element with differing numbers of neutron and different masses.

Answer 22

Isotopes

Question 23

Atomic number is the______

Mass number is the ________

Answer 23

Protons; total # of protons and neutrons

Question 24

Tells the mass number and percent abundance for isotopes wherein charged plates create an environment of high kinetic energy to charge the entering particles

Answer 24

Mass spectrometer

Question 25

In a mass spectrometer, what happens when positive charges pass through negative plates with the same kinetic energy?

Answer 25

They accelerate kinetic field

Question 26

T or F: the lighter isotopes with the lower mass number move faster and will get to the detector earlier

Answer 26

True

Question 27

What does the detector do in a mass spectrometer?

Answer 27

Compares the isotopes that arrive and the time it takes to arrive. It only measures time which is used to calculate mass and abundance

Question 28

What does the peak of te graphs denote in a mass spectrometer graph?

Answer 28

Relative? abundance

Question 29

T or F: the slower the isotope, the later it appears in te graph

Answer 29

True

Question 30

T or F: the graphs in mass spectrometer can differentiate between the total number of protons and neutrons

Answer 30

False, it cant; more advance tests must be used

Question 31

What are the six steps in mass spectrometry?

Answer 31

→ Injection (The species is introduced into the spectrometer)
→ Vaporizer (Molecules are converted to gas via heat)
→ Ionization (high voltage) (The vapors are bombarded by an electron beam, converting the vapor into ions (Electron Ionization))
→ Acceleration (The double negative plate creates a kinetic filed causing the ions to accelerate)
→ Ion Drift (The species travels across the medium)
→ Detector (Detects the analytes)

Question 32

Step in MS wherein vapors are bombarded by an electron beam, converting the vapor into ions

Answer 32

Ionization (3rd)

Question 33

Step in MS wherein species is introduced into te spectrometer

Answer 33

Injection (1st)

Question 34

Step in MS wherein species travel across the medium

Answer 34

Ion drift

Question 35

Step in MS where molecules are converted to gas by heat

Answer 35

Vaporization

Question 36

Step in MS wherein the double negative plate creates a kinetic field causing the ions to accelerate

Answer 36

Acceleration