Spectroscopy

Question 1

What is spectroscopy?

Answer 1

Study of interaction of electromagnetic waves with matter

Question 2

What is the application of spectroscopy?

Answer 2

Quantitative estimation
Kinetics of reaction
Structure determination
Identification of unknown solute

Question 3

Name the techniques for the following electromagnetic radiation
X Rays
UV
Visible
IR
Microwave
Radiowave

Answer 3

X rays crystallography
UV Vis Spectroscopy
IR spectroscopy
Microwave spectroscopy
Electron spin reversal spectroscopy and NMR

Question 4

Two types of spectroscopy?

Answer 4

Absorption and emission spectroscopy

Question 5

Beer Lamberts Law

Answer 5

Absorbance is directly proportional to solute concentration and path length of the light travelled.

Question 6

What is the unit of absorbance?

Answer 6

Unit less

Question 7

What is the unit of molar extinction coefficient?

Answer 7

M-¹ cm-¹

Question 8

Formula of absorbance?

Answer 8

A = log10 l°/l
A = log 10 1/T
A = 2 - log10 (%T)

Question 9

What is the application of colorimetre?

Answer 9

Quantitative estimation

Question 10

What is the range of far UV absorption and near UV absorption?

Answer 10

Far - 190 to 250
Near - 250 to 280

Question 11

When does DNA or RNA and peptide bonds get absorbed in UV spectroscopy?

Answer 11

DNA and RNA - 250 nm
Peptide bonds - 210 nm

Question 12

What range of UV spectroscopy does protein(tryptophan and tyrosine), phenylalanine and disulfide linkage gets absorbed?

Answer 12

Protein
Tryptophan - 280
Tyrosine - 270
Phenylalanine - 260
Disulphide linkage - 255

Question 13

Which of the near or far UV region is impossible?

Answer 13

Sigma to sigma star
Pie to sigma star

Question 14

What is the ratio of pure DNA 280/260

Answer 14

1.8

Question 15

What is the ratio of pure RNA 280/260?

Answer 15

2.0

Question 16

What contributes to intrinsic fluorescence?

Answer 16

Aromatic amino acid

Question 17

What is the application of IR spectroscopy?

Answer 17

Identification of chemical composition

Question 18

What is the application of circular dichroism?

Answer 18

Identification of secondary structure and conformational changes due to protein - protein interaction.

Question 19

How many peaks will be developed in circular dicorism for the following: -
a helix
B helix
Random coil

Answer 19

a helix - one positive and two negative
B helix - one positive and one negative
Random coil - one strong negative and one weak positive

Question 20

What is the application of NMR?

Answer 20

Structure determination
Functional group analysis
3D structural of biomolecule in their native state

Question 21

Name two NMR active atoms.

Answer 21

1H, 13 C

Question 22

What is stoke shift?

Answer 22

The difference in absorption peak and emission peak in a graph.

Question 23

Name the two types of transition in emission spectroscopy.

Answer 23

Non radiative and radiative

Question 24

What is a fluorophore?

Answer 24

A component that causes a molecule to absorb the energy of a specific wavelength and re-emit the energy.

Question 25

Give an example of vibrational spectroscopy.

Answer 25

IR spectroscopy

Question 26

Does IR spectroscopy induce electronic transition?

Answer 26

No

Question 27

Name the instrument that determines the IR absorption spectrum for the compound.

Answer 27

Infrared spectrometer

Question 28

Name the two regions in the IR spectra.

Answer 28

Functional group region and fingerprint region

Question 29

What is the range of fingerprint region?

Answer 29

1200 to 700 cm-¹

Question 30

Does NMR spectroscopy detect any nucleus?

Answer 30

No, only those nuclei which have magnetic properties.

Question 31

If the number of neutrons and number of protons are even then individual spin is what and overall spend becomes what?

Answer 31

Individual spin is paired and overall spin becomes zero.

Question 32

If the number of neutrons and number of protons are both are odd then the nucleus has what kind of spin?

Answer 32

Integer spin

Question 33

If the number of neutrons plus the number of protons is odd then what kind of spin does nucleus have?

Answer 33

Half integer spin

Question 34

Electrons with what kind of spin have covalent bond?

Answer 34

Opposite spin

Question 35

Which have lower energy, positive half spin or negative half spin?

Answer 35

Positive half spin

Question 36

NMR is detected in what?

Answer 36

NMR spectrometer

Question 37

What is the full form of TMS?

Answer 37

Tetramethylsilane

Question 38

Raman spectroscopy

Answer 38

Involves the scattering of radiation by sample

Question 39

Inelastic scattering?

Answer 39

The light is scattered at the frequency that differ from the incident light.

Question 40

Elastic scattering?

Answer 40

When the light is scattered at the same frequency as the incident light

Question 41

What does mass spectrometry determine?

Answer 41

Mass of an ionic species

Question 42

How does mass spectrometry determine mass?

Answer 42

By measuring mass to charge ratio

Question 43

Name the three basic components of mass spectrometry.

Answer 43

Ionisation source Mass analyser Detector

Question 44

What gives the sample charge?

Answer 44

Ionisation

Question 45

Full form of MALDI.

Answer 45

Matrix assisted laser desorption/ionisation

Question 46

Which matrix is commonly used in the MALDI?

Answer 46

Aromatic compounds

Question 47

What is MALDI?

Answer 47

It is a type of desorption ionisation in the mass spectrometry ionisation

Question 48

What happens in the ionization process of the mass spectrometry?

Answer 48

Conversion of solute to the gas phase and maintaining their charge.

Question 49

What happens in mass analysers of the mass spectrometry?

Answer 49

The sample are passed into mass analyser where they are separated according to their mass to charge ratio.

Question 50

Name the most common type of mass analyser.

Answer 50

Time of flight (TOF)

Question 51

How does TOF determine the mass?

Answer 51

It is based on the different velocity rate of different ions. The smaller ions move faster than larger ions.

Question 52

Application of mass spectrometry.

Answer 52

To determine the mass of an unknown compound Determine the structure

Question 53

How to determine the sequence of polypeptide?

Answer 53

Tandem MS or MS-MS