Analytical methods Chapter 5 Flashcards

1
Q

What is Spectrophotometric measurement?

A

It is a measurement of light intensity in a narrower wavelength

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2
Q

What is Photometric measurement?

A

It is a measurement of light intensity without consideration of its wavelength

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3
Q

Is described as photons of energy traveling in waves

A

Electromagnetic radiation

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4
Q

What is the formula of the Beer’s law?

A

Concentration of a substance is directly proportional to the amount of light absorbed or inversely proportional to the logarithm of the transmitted light

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5
Q

What is the use of Light source?

A

Incident light for the system

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6
Q

What are the common source of light used near infrared regions?

A

Incandescent tungsten and Tungsten light bulb

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7
Q

What are the alternatives used for UV spectrum?

A

Deuterium discharge lamp and mercury arc lamp

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8
Q

What is the use of Entrace slit?

A

It minimizes the unwanted straylight

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9
Q

What is Straylight?

A

It is a wavelength outside the band which can affect the measurement and cause absorbance error

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10
Q

What is the use of monochromator?

A

It isolates specific or individual wavelength of light

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11
Q

Kinds of monochromator

A

Prisms, Diffraction gratings and Interference Filters

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12
Q

The principle of prism

A

A narrow beam of light focused on a prism is refracted as it enters the more dense glass

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13
Q

Most commonly used monochromator that consists of many parallel grooves

A

Diffraction gratings

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14
Q

Principle of constructive interference

A

Light waves enter one side of the filter and are refracted at the 2nd surface

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15
Q

What is the use of Exit Slit?

A

It controls the width of the light beam or band pass

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16
Q

The narrower the light beam

A

the greater the resolution

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17
Q

sample cell/ absorption cell/ analytical cell

A

cuvet

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18
Q

kinds of cuvet and some definition

A

Alumina Silica glass- simple/ older
Quartz/ Plastic- used for UV spectrum
Borosilicate glass- can stand increase temperature
Soft glass- Common glass

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19
Q

scatter light and should be discarded

A

scratches

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20
Q

Produces etching and dissolves glass

A

Alkaline solutions

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21
Q

What is a Photodetector?

A

It converts Light energy to Photoelectric Energy

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22
Q

Kinds of Photodetectors:

A

Photocell, Phototube and Photomultiplier tube

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23
Q

Requires external voltage and it gives off electron when light energy strikes it

A

Phototube

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24
Q

Simplest detector and no external voltage

A

Photocell

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25
Q

On a plate of iron covered with transparent layer of silver

A

Selenium

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26
Q

Most common type which can detect low level of light and amplifies radiant energy 200x

A

Photomultiplier tube

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27
Q

What is Sensitivity and Specificity?

A

Sensitivity is a term that can measure even the smallest movement of light while Specificity is a term that can only detect a specific light

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28
Q

It detects less amount of light and not as sensitive as photomultiplier tube

A

Phototransistors and Photodiode

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29
Q

moving needle on a dial or a digital display that indicates the amount of light passing

A

Galvanometer/ Ammeter

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30
Q

Splits the monochromator light into two components

A

Double-beam Spectrophotometer

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31
Q

Beam passes through:

A

1st-sample

2nd- reference solution or blank

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32
Q

Used to check wavelength accuracy

A

Didychium or holmium oxide filter

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33
Q

Reagent blank

A

Blanking technique

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34
Q

light emitted by a single atom burned in flame and measurement of excited atoms (Na, K, Li)

A

Flame-emission spectrophotometry

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35
Q

Principle of Flame-emission photometry

A

Excitation of electrons from lower to higher energy state

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36
Q

Serves as a light source and cuvette for FEP?

A

Flame

37
Q

Serves as a monochromator in FEP?

A

Filter

38
Q

Components of FEP

A

Nebulizer, Burner and Monochromator system

39
Q

Deliver a fine spray of sample

A

Nebulizer

40
Q

Strikes the photomultiplier tube

A

Monochromator system

41
Q

What is the light source used in Atomic absorption spectrophotometry?

A

Hollow cathode lamp

42
Q

Light is not excited, unionized and at a ground state?

A

Atomic absorption spectrophotometry

43
Q

Unexcited trace metals

A

Ca++ and Mg++

44
Q

Converts Ions to atoms

A

Atomizer (Nebulizer grapite furnace)

45
Q

Used to modulate light source

A

Chopper

46
Q

Principle of Fluorometry

A

amount of light emitted by a molecule after excitation by electromagnetic radiation and uses 2 monochromator

47
Q

light source used in fluorometry

A

mercury arc and xenon lamp

48
Q

light detector used in fluorometry

A

Photomultiplier tube

49
Q

difference between primary filter and secondary filter

A

The primary filter is the selection of wavelength that is best absorbed by the solution while the secondary filter prevent incident light from striking the photodetector

50
Q

Advantage of Fluorometry

A

1000x more sensitive than most spectophotometry

51
Q

Disadvantage of Fluorometry

A

Quenching - sudden change in temperature and reduces intensity of fluorescence

52
Q

Principle of Chemiluminescence

A

Exciting molecules by chemicals and requires no excitation radiation and monochromator (MOLECULES IN UNEXCITED STATE)

53
Q

Advantage of Chemiluminescence

A

Speed (10s) - Picomdar detection

Simple instrumentation

54
Q

Principle of Turbidimetry

A

Amount of Light blocked by suspension particles and is dependent on particle size and concentration

55
Q

Abundant in blood sample

A

Albumin

56
Q

Principle of Nephelometry

A

Light scattered by the small particles is measured at an angle forward to the incident light

57
Q

the higher the scattered light equals the no. of particle

A

the increase in concentration

58
Q

Process of separating by electric current

A

Electrophoresis

59
Q

2 types of Electrophoresis

A

Iontophoresis and Zone Electrophoresis

60
Q

Migration of small ions

A

Iontophoresis

61
Q

Migration of charged macromolecules in porous support

A

Zone electrophoresis

62
Q

Protein are negatively charged and they moved toward the _______

A

anode

63
Q

The 2 Buffers and their corresponding pH

A

Barbital (veronal) pH 8.6

Tris-boric EDTA pH 8.7

64
Q

Acidic and basic, determine the net change on a protein (electrophoretic mobility)

A

Electrophoresis

65
Q

3 supporting media

A

Cellulose acetate, Agarose gel, Polyacrylamide gel

66
Q

separates serum proteins into 5 bands (no. of fractions)

A

Cellulose acetate

67
Q

Agarose gel has how many bands?

A

10-15 bands

68
Q

Polyacrylamide gel has how many bands?

A

720 bands

69
Q

Migration is controlled by

A

net change of the partilly, Particle size and shape, Electric fields, supporting media and Temperature

70
Q

movement of buffer and solvent relative to their fixed support

A

Electroendosmosis

71
Q

separating molecules migrate(PH gradient) and proteins of identical size but with different net changes

A

Isoelectric Focusing

72
Q

Separation is performed in narrow-bore fuse silica capillaries

A

capillary electrophoresis

73
Q

Separation sample of mixtures between mobile and stationary phase

A

Chromatography

74
Q

Modes of separation

A

Adsorption (Liquid-Solid Chromatography), Partition ( Liquid-Liquid Chromatography), Steric Exclusion, Ion exchange

75
Q

Based on the competition of adsorptive sites (stationary phase)

A

Adsorption (Liquid-solid Chromatography)

76
Q

Separation of solute based on the relative solubility of the compound

A

Partition

77
Q

Separation by magnitude and charge of ionic species

A

Ion exchange

78
Q

Gel filtration, Gel permeation or molecular chromatography and separates solutes

A

Steric Exclusion

79
Q

2 stationary phase

A

cation- exchange resin

Anion- exchange resin

80
Q

Side chains of cation

A

H+ ions

81
Q

Side chains of Anion exchange

A

OH-

82
Q

2 Types of Chromatography

A

Planar and Columnar

83
Q

2 types of Planar Chromatography

A

:Paper and Thin layer Chromatography (drug screening)

84
Q

Intube or coated column separation

A

Columnar Chromatography

85
Q

distribution of solute between a liquid mobile phase and a stationary phase

A

Liquid Chromatography

86
Q

used for fraction of drugs, hormones, lipids, carbohydrates and proteins

A

HPLC (High performance liquid chromatography)

87
Q

pressure for fast separation of thermos substance

A

HPLC

88
Q

used to separate mixture of compounds that are volatile

A

Gas chromatography