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Lab Tech > Chroma And Spectro Methods > Flashcards

Chroma And Spectro Methods Flashcards

1
Q

Is a technique in which components of a micture are separated based on differences in the rates at which they are carried through a stationary phase by a mobile phase

A

Chromatography

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2
Q

The ____ is a liquid or gas that moves over or through the stationary phase carrying with it the analyte mixture.

A

Mobile phase

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3
Q

The ____ is a solid or a liquid film coated in a solid substrate that is fixed in a place either in a coloumn or in a planar surface

A

STATIONARY Phase

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4
Q

The most common mobile phases in GC includes

A

He, Ar, N2

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5
Q

The most common mobile phases in gas chroma includes

A

He, Ar, N2

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6
Q

The type of column used in Gas to liquid GC with shorter retention time

A

Capillary column

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7
Q

The type of column used in Gas to solid GC with longer retention time

A

Packed column

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8
Q

The principle of this chroma tech is adsorption. Wsuch that when a mixture of a component are inteosuced, they travel acc to their relative affinities toward the stationay phase. With more affinity towards the adsorbent travels slower, and with those who have less affinity to the adsorbents will travel faster

A

Liquid Chromatography

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9
Q

This part of HPLC separates the mobile phase from the sovent reservior and forces it thdough the systems column and detector and maintains constant flow of mobile phase regardless of the pressure caused by the resistance of packed column.

A

Pump in HPLC

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10
Q

An elution with a SINGLE solvent mixture of a constant composition is termed an_____

A

Isocratic elution

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11
Q

An elution having two or sometimes more solvent systems that differ significantly in parity are used and varied in composition during the separation

A

GRADIENT ELUTION

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12
Q

Sample in HPLC is injected using a

A

Loop injector

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13
Q

This kind of column in HPLC is responsible for separating

A

Analytical column

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14
Q

This kind of column is placed before analytical column to avoid contamination

A

Guard column

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15
Q

These are the most popular LC Detectors. They are based on

A

UV or Visible radiation

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16
Q

The most widely used of HPLC is the

A

Partition Chromatography

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17
Q

The stationary pjase is a second liquid that is immiscible with the liquid mobile phase.

A

Partition chroma

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18
Q

The stationary phase is a mon polar often hydrocardin and the mobile phase is a polar solvent in reversed phase chroma

A

Normal phase chroma

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19
Q

These are based in the exchange of equilibria between ions in splution and ions of similar charges on the surface of an insoluble HIGH MW solid

A

Ion Exchange

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20
Q

The most common active sites for cation exchange resins are the

A

Strong acids SO3-H+
Weak acids COO-H+

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21
Q

The most common anion exchangers contain the strong base

A

Ammonia -OH groups

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22
Q

Is a powerful technique that is particularly applicable to high molecular weight sepcies.

A

Size exclusion

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23
Q

This is also called gel chromatography

A

Size exclusion

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24
Q

This consists of small 10microns of silical or polymer particles containing a network uniform pores into which solutes and solvent molecules can diffuse

A

Size exclusion or gel chroma

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25
Q

Chromatography based in hydrophilic packings was once called

A

Gel filtration

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26
Q

Chromatography based on hydrophobic packings

A

Gel permeation

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27
Q

These methods are complementary

A

Gel filtration and permeation

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28
Q

Gel filtration is apllied to water soluble samples and gel permation is used for substances in less polar organic solvents. T or F

A

Trueee

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29
Q

Via differences in affinity. It involves covalently bonding a reagent to a solid support

A

Affinity Chromatography

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30
Q

A typical affinity ligands are antibodies, _____ or other molecules that reversibly and selectively bind to analyte molecules in the sample

A

Enzymes inhibitors

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31
Q

Then sample passes through the column, only the molecule that selectively bind to the affinity ligands are reatined. True or false

A

True

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32
Q

The study of interaction of electromagnetic radiation and matter

A

Spectroscopy

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33
Q

This is only possible if your photon interact with the sample which leads to the change in one or more of its characteristics properties

A

Spectroscopic measurement

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34
Q

In this spectroscopy, a photon is absorbed by an atom pr a molecule which undergoes a transition fron lower energy state(ground state) to a higher energy state (excited state). The type of transition depends on the photons energy

A

Absorption spectroscopy

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35
Q

Via: Absorption energy transfer
Region of Electromagnetic spectrum : gamma ray
Spectro tech:

A

Mossbauer Spectro

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36
Q

Via absorption energy transfer
Region of EM spectrum: Infrared
Spectro Technique:______

A

Raman spectro

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37
Q

Readio wave EM Spectrum via absorption
Type of technique ______

A

Electron spin resonance
NMR

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38
Q

In emission spectro, an atom or molecule in an excited state returns to a lower energy state and the excess energy is often released as a _____

A

Photon

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39
Q

Emission following the absorption of a photon is called

A

Photoluminiscence

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40
Q

The emission following the chemical reaction is _____

A

Chemiluminiscence

41
Q

A ___emits radiation over a broad range of wavelength with relatively smooth variation intensity

A

Continuum source

42
Q

A ______ source emits radiation at selected wavelength

A

Line

43
Q

Wavelength selector which provides continuous variation of Wavelength

A

Monochromator

44
Q

A____ is a device that identifies, records, or indicates the change in one of the variables in its environment such as pressure, temperature or EMR

A

Detector

45
Q

This converts the various type of chemical and physical quantities into electrical signal such as electrical charge, current or voltage

A

Transducer

46
Q

These are among the most widey used transducers for dwtecting UV/Vis radiation having major advantage in internal amplification with 10^6-7 electrins are produced at the anode for each photon that strikes the photocathode of PMT

A

Photomultiplier tubes

47
Q

This can also be used to amplify the signal from the detector, remove noise by filtering or mathematically transform the signal.

A

Signal processor

48
Q

The radiation from the instrument that is outside the nominal wavelength band chosen for the determination often the result of scattering and reflection off the sources of gratings, lenses or mirrors, filters and windows. Or often its wavelength differs greatly from that of the principal radiation and maybe it may not have passed through the sample

A

Stray light

49
Q

This is employed mainly for quantitative analysis and most extensively in lab than any other single technique

A

UV and Vis spectro

50
Q

When a molecule absorbs EMR the number of photons passing through sample decreases (______)

A

Attenuation

51
Q

The measurement of attenuation in photons is called

A

Absorbance

52
Q

This is the plot of absorbance as a function of the photons energy

A

Absorbance spectrum

53
Q

The ratio of the radiant power passing through a sample to that from the source

A

Transmittance

54
Q

-log T

A

Absorbance

55
Q

Transmittance of light decrease with an increase of sample thickness

A

Lambert

56
Q

Transmittance of light decrease as concentrations of absorbing species increases

A

Beer

57
Q

These two relationships
The deacrease in the transmittance of ight with respect to the increase of sample thickness and the transmittance of light decrease as the concentrationof absorbing species increase combines to form

A

Beer’s Law

58
Q

The limitations in plotting beers law includes:
-light should be monochromatic
-light that reaches detector should be transmitted light alone
-there should only be one absorbing specie
-applicable only to diluted solutions

A

True

59
Q

The simplezt instrument for UV vis absorption. It uses an single optical FILTER to isolate band of radiation and a single optical path between source and detector. It is also inexpensive, rugge, and easy to maintain and portable

A

Filter photometer

60
Q

Source-monochromator
Sample, Blank
Detector

A

Single beam spectrophotometer

61
Q

Source-monochromator
Chopper >mirror>sample_blank>mirror_mirror
Sample to detector> signal processor
Double mirror

A

Double beam

62
Q

Source chopper sample blank
Sample to GRATINGS- detectors-signal processor

A

Diode array spectrophotometer

63
Q

This is the process in which a sample is convefted into a gas phase atoms or elementary atoms

A

Atomization

64
Q

In this atomizers sample are introduced in a steady and continuous stream

A

Continuous atomizers

65
Q

In this atomizers, individual samples are introduced by a syringe or autosampler

A

Discrete atomizers

66
Q

This uses single beam or double bram spectrophotometer and widely used for the analysis of trace metals in a variety of a sample matrices.

A

AAS

67
Q

Hallow cathode lamp-chopper
Flame- sample
Monochromator
Detector
Electronics readout (amplifier tuned to chopper frequency)

A

AAS

68
Q

This spectro is suited for a multi elemental analysis because all analytes in a sample are excited simultaneously, and used for the analysis for trace metals in variety of sampme matrices. This uses a mutichannrl atomic emmision spectrometer which simultaneously analyze several elements appx having 48-60 detectors

A

Atomic Emission spectroscopy

69
Q

Spec technique used for measuring molecular weight and determining molecular formula or organic compound

A

Mass spectrometry

70
Q

In _____ a sample undergoes Vaporization, ionization, acceleration, deflection and detection. Due to a beam of a high energy electrons, the sample produces an instable radical cation(M+) which decomposes to a smaller fragment. This cations based on theur Mass to charge ratios (m/z) are deflected by different amounts

A

mass spectrometer,

71
Q

A ______ plots the intensity of each ion versus it m/z ratio

A

Mass spectrum

72
Q

The talest peak in the mass spectrum is the ____

A

Base peak

73
Q

These formation are caused by the other peaks in the mass spectrum which molecular ions are decomposed into lower molecular weight fragments

A

Fragmentation

74
Q

Spectro technique in identifying functional groups

A

IR spectroscopy

75
Q

Sample preparation for _____ spectro analysis:
Sample must be mull, solid run in, case film, and pressed pallet

A

IR

76
Q

Liquid samples in IR spectro must be sandwich using purified alkali halides such as

A

NaCl

77
Q

Light passes through a sample which casues changes in the vibrational morions of a molecule. That frequencies that match the vibrational frequencies are absorbed, and the remaining lihjt is transmitted to a detector

A

IR spectrometer

78
Q

In IR spectroscopy, different kinds of ____ vibrate at different frequencies so they absorb different frequencies of IR light.

A

Bonds

79
Q

A _____ plots the amount of transmitted light versus its wavelength

A

Spectrum

80
Q

An ____ specturm has a broad lines as compared to the sharp peaks in mass spectra

A

IR

81
Q

Region having less than 1500cm^-1 containing complex set of bands and is unique for every compound

A

Fingerprint region

82
Q

Region of functional group in IR spectro

A

4000-1500

83
Q

Approximate IR absorption of
O-H

A

3600-3200 cm^-1

84
Q

Approximate IR absorption of
O-H

A

3600-3200 cm^-1

85
Q

Appx absorption of N-H in IR spectrum

A

3500-3200cm^-1

86
Q

Appxx IR absorption of C-H

A

~3000cm^-1

87
Q

Appxx absorption of C—C
C—N
(TRIPbond)
in IR spectrum

A

2250cm^-1

88
Q

appx absorption of C–O in IR spectrum

A

~1700cm^-1

89
Q

Appx absorption of C–C in IR spectrum

A

1650cm^-1

90
Q

In IR spectro, the lighter the atoms and the stronger the bonds the ______

A

Higher the frequency

91
Q

The flow frequency radio waves used in this spectro can change the nuclear spin of some elements including 1H and 13C. The applied magnetic field and frequency of radiation used for resinance are two variables

A

NMR spectro

92
Q

The nucleus is in the _____ when it absorbs RF radiation and spin flips to a higher energy state. Such that protons of different environments absorb at different frequency and so they are distinguished

A

resonance

93
Q

The nucleus is in the _____ when it absorbs RF radiation and spin flips to a higher energy state. Such that protons of different environments absorb at different frequency and so they are distinguished

A

resonance

94
Q

The nmr spectrum is a plot of the intensity of a signal against its ______ in ppm. Their absorption appear as a sharp peak

A

Chemical Shift

95
Q

The external standard uaed ____ is a volatile and inert compound that gives a single peak upfield from other typical nmr absorption

A

TETRAMETHYLSILANE

96
Q

The number, position, intensity, and spin splitting of signals in nmr spectrum provides information about

A

Structure of a compound

97
Q

Loosely held pi electrons can either be shielded or signal appears _____

A

Upfield

98
Q

The loosely held pie electrons can also be deshield or signal appears

A

Downward

Lab Tech (4 decks)

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