ANALYTICAL METHODS AND INSTRMENTATION Flashcards

1
Q

what is the 4 basic discipline of analytical chemistry

A

Spectrometry
Luminescence
Electroanalytic methods
Chromatography

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2
Q

what is under the spectrometry

A

spectrophotometry
atomic absorption spectrometry
mass spectrometry

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3
Q

what is under the luminescence

A

fluorescence
chemiluminescence
nephelometry

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4
Q

what is under the electroanalytic methods

A

electrophoresis
potentiometry
amperometry

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5
Q

what is under the chromatography

A

gas, liquid, and thin-layer

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6
Q

both spectrometry and luminescence is similar in using radiant energy, but what is the difference, how do we differentiate them both?

A

the light produced by S will then be converted into electrical energy for the signaling of the result while L is focused on the detection of the light as a potential marker of the analyte.

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6
Q

what are the 2 primary considerations in colorimetry analysis

A

 Quality of color
 Intensity of color

QUALITY AND INTENSITY

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6
Q

In spectro, light is either __ or ___

A

absorbed and transmitted

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6
Q

what is the similarity of spectrometry and luminescence

A

both uses radiant energy or light

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6
Q

relationship of the color of the result experimentation and the amount of analyte

A

directly proportional

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6
Q

is spectrophotometry a colorimetry method analysis?

A

yes

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6
Q

a type of method associated with the color produced in the experimentation.

A

colorimetry

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6
Q
  • most commonly used light source in the near uv, near visible, and near infrared
A

tungsten filament

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6
Q

a kind of colorimetry that uses the eyes in determining the end point

A

Visual Colorimetry

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6
Q

solutions were able to get a colored reaction is because of the addition of

A

chromogen

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6
Q

one of the photoelectric colorimetry type which is about the

measurement of
light intensity in a much narrower wavelength. It
uses a device (prisms and/or gratings) to disperse
the source of light into a continuous spectrum

A

SPECTROPHOTOMETRY/ spectrophotometric measurements

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6
Q

photoelectric colometry used two instrument such as the

A

Spectrophotometry and filter photometry

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6
Q

a kind of colorimetry that uses equipment or electricity

A

Photoelectric Colorimetry

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6
Q

photoelectric colorimetry uses instrument such as the spectrophotometry and the filter photometry in order to ____

A

isolate the discrete portion of the spectrum for the purpose of measurement

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6
Q

one of the type of photoelectric colorimetry that is about the

measurement of light intensity of MULTIPLE WAVELENTH. It uses filter to
isolate part of the spectrum

A

FILTER PHOTOMETRY/ photometric measurement

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6
Q

monochromators used in spectrophotometry?

A

prism and diffraction grating

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6
Q

example of visual colorimetry

A

reagent strip

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6
Q

monochromators used in filter photometry or photometric measurement

A

filters

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6
Q

2 types of photoelectric colorimetry

A

spectrophotometric measurement
photometric measurement

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6
Q

They are PHOTONS of energy traveling in a wavelike manner.

A

Electromagnetic energy

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6
Q

The shorter the wavelength, the ____ the
electromagnetic energy.

lighter or heavier?

A

lighter

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6
Q

how photons are being transmitted?

A

Via electromagnetic waves

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6
Q

electromagnetic waves are characterized by the two named

A

frequency and wavelength

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6
Q

distance between peaks as light is envisioned to travel in
wavelike manner.

A

wavelength

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6
Q

number of vibrations of wave motion per
second

A

frequency

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6
Q

range of visible spectrum in nanometers

A

400 -700 nanometers

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7
Q

the relationship between wavelength and energy is described as/with

A

PLANCK’S FORMULA E=hv

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8
Q

what is the h and v in the plank’s formula?

A

h - constant (6.62 x 1027 erg sec)
v → frequency

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9
Q

wha is the relationship of the wavelength and the frequency at each other

A

they are inversely proportional to each other

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10
Q

represents the wavelength in nanometers at peak transmittance

A

nominal wavelength

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11
Q

a slight error in wavelength adjustments can introduce a ___

A

significant error in absorbance readings

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12
Q

wavelength accuracy is the wavelength indicated on the ___ is the actual wavelength of light passed by the monochromator

A

control dial

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13
Q

is used to check wavelength accuracy (wavelength calibration)

A

didymium or holmium oxide filter

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14
Q

for quality control what is the one we used to calibrate wavelength?

A

didymium or holmium oxide filter

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15
Q

it involved measurement of the light transmitted by a solution to determine the concentration of the light-absorbing substances in the solution

A

spectrophotometry

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16
Q

States that the concentration of a substance is directly
proportional to the amount of the light absorbed or
inversely proportional to the logarithm of transmitted
light.

A

Beer’s law or Beer Lambert’s law

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17
Q

this law Deals with the concentrations of a substance

A

beer’s law

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18
Q

ratio of the radiant energy transmitted, divided by
the radiant energy incident on the sample.

A

transmittance

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19
Q

what is the formula for the transmittance

A

%T = It/Iox100

It = light transmitted
Io = incident light

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20
Q

The amount of light absorbed by the molecule

A

absorbance

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21
Q

what are the 6 basic components of spctrophotometer

A

 Light source
 Device to isolate light of a desired wavelength
 Cuvet
 Photodetector
 Read-out device
 Data system

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22
Q

Provides radiant energy in the form of
visible or non-visible light that may pass through the
monochromator.

A

light source

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23
Q

2 types of spectrophotometer

A

single beam spectrophotometer
double beam spectrophotometer

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24
Q

It is the simplest type of absorption spectrometer.

A

Single beam spectrophotometer

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25
Q

It is designed to make one measurement at a time at one specified
wavelength

A

Single beam spectrophotometer

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26
Q

type of spectrophotometer

The absorption maximum of the analyte must be known in advance
when a ___ is used.

A

single-beam instrument

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27
Q

a type of spectrophotometer that only has 1 cuvette holder

A

single beam spectrophotometer

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28
Q

a type of spectrophotometer that Splits monochromatic light into two components

A

double beam spectrophotometer

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29
Q

double beam spectrophotometer has 2 beam,
the first beam is for __
and the second beam is for ___

A

1st - sample
2nd - blank solution

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30
Q

in the double beam spectrophotometer, we can add the additional beam which it can __

A

which it can corrects the variation of the light source intensity

31
Q

in this type of spectrophotometry, the absorbance of the sample can be recorded directly as the electrical output of the sample beam

A

double-beam spectrophotometer

32
Q

2 types of double beam spectrophotomeer

A

double beam in space
double beam in time

33
Q

a type of double-beam spectrophotometer that has 2 photodetectors

for the sample and the reference beam

A

double beam in space

34
Q

a type of double beam spectrophotometer that uses one photodetector
and alternately passes the monochromatic light
through the sample cuvet and then reference
cuvet using a chopper Sample

A

double beam in time

35
Q

7 basic components of single or double-
beam configuration spectrophotometer:

A
  1. Stable source of radiant energy
  2. Filter that isolates a specific region of the electromagnetic spectrum
  3. Cuvets
  4. Sample holder
  5. Radiation detector
  6. Signal processor and
  7. Readout device
36
Q

first part of the spectrophotometer

A

radiant or light source

37
Q

It provides polychromatic light and must generate sufficient
radiant energy or power to measure the analyte of interest.

A

light/radiant source

38
Q

An intense beam of light is directed through the
monochromator and the sample.

A

light/radiant source

39
Q

To give accurate absorbance measurements throughout its
absorbance range, its response to change in light intensity
must be ____.

A

LINEAR

40
Q

the ability to absorb energy n a particular wavelength is called

A

linear or line spectrum

41
Q

what are the 2 types of light source

A

continuum and line source

42
Q

a type of light source that emits radiation that CHANGES IN INTENSITY

A

continuum

43
Q

example of continuum light source

A

tungsten, deuterium, and xenon lamps

44
Q

this type of continuum light source is routinely used to provide UV radiation in analytic spectrometers

A

deuterium lamp

45
Q

this type of continuum light source produces a continuous source of radiation which covers both UV and visible range

A

xenon discharge lamp

46
Q

another type of light source that emits LIMITED RADIATION and
wavelength; uses an intense beam of light directed through the monochromator and the sample

A

line source

47
Q

example of lamp under line source

A

mercury and sodium vapor lamps in spectrophotometer (UV and visible regions)
hollow cathode lamp (AAS - atomic absorption spectro)

48
Q

last example we can use for line source

A

LASER (LightAmplification by Stimulated Emission of Radiation)l

49
Q

a light source we can use for AAS - atomic absorption spectro

A

hollow cathode lamp

50
Q

what are the factors we need to consider for choosing a light source

A

o Range
o Spectral distribution
o Source of radiant production
o Stability for the radiant energy
o temperature

51
Q

what are the alternatives for tungsten bulb

A

+ Mercury arc (visible and UV)
+ Deuterium lamp (165nm) - UV
+ Hydrogen lamp - UV
+ Xenon lamp - UV
+ Merst glower -IR
+ Globar (silicone carbide) - IR

52
Q

minimizes UNWANTED or stray light and
prevents the entrance of scattered light into the monochromator system

A

entrance slit

53
Q

Stray light causes systematic error; causes loss of linearity

true or false

A

true

54
Q

Isolate specific wavelength of light

A

monochromator

55
Q

light radiation of a single wavelength

A

monochromator light

56
Q

a monochromator of spectro

wedge-shaped pieces of glass, quartz, NaCl, or some
other material that allows transmission of light.

A

prism

57
Q

Disperses white light into a continuous spectrum of
colors based on variation of refractive index for different
wavelength.

A

prism

58
Q

the width of the spectral
transmittance curve at a point equal to ½ the peak
transmittance (spectral purity)

A

spectral bandwidth

59
Q

the most commonly used type of monochromator

A

diffraction grating

60
Q

has small grooves cut at such as angle that each groove
behave like a very small prism.

A

diffraction grating

61
Q

wavelength are bent as they pass a sharp corner

A

diffraction grating

62
Q

Advantage of gratings over prisms

A

 Produces LINEAR SPECTRUM and therefore maintaining a
constant and pass which is simple.
 Can be used in the regions of spectrum where light energy is absorbed by glass prism.

63
Q

the 3rd type of monochromator used for filter protometry

A

filter

64
Q

These are simple, least expensive, not precise but useful.

A

filters

65
Q

These are made by placing semi-transparent silver films on
both sides of a dielectric such as magnesium fluoride.

A

filters

66
Q

light waves enter
one side of the filter and are reflected at the second
surface

A

constructive interference

67
Q

a type of monochromator that usually pass a wide band of radiant energy and have a
low transmittance of the selected wavelength.

A

Filters

68
Q

It controls the width of light beam (bandpass)

A

exit slit

69
Q

allows only a
narrow fraction of the spectrum to reach the sample cuvette.

A

exit slit

70
Q

__ is the total range of wavelengths transmitted

A

bandpass

71
Q

Accurate absorbance measurement requires a bandpass less than
___ the natural bandpass of the spectrophotometer.

A

1/2

72
Q

EXPLAIN THE RELATIONSHIP OF THE BANDPASS AND THE RESOLUTION

A

narrower the bandpass, the greater the
resolution.

73
Q

___ of the spectrophotometer is reflected by the
bandpass,

A

Spectral purity

74
Q

It is also called absorption cell/analytical cell/sample cell.

A

Cuvet

75
Q

It holds the solution whose concentration is to be
measured

A

CUVET

76
Q

what are the kinds of cuvets

A

+ Alumina silica glass-
+ Quartz/plastic
+ Borosilicate
+ Soft glass

77
Q

a type of cuvet that is most commonly used (can be used
in 350-2000m)

A

alumina silica glass

78
Q

a type of cuvet that is used for measurement of solution
requiring visible and ultraviolet spectra

A

quartz/plastic

79
Q

a type of cuvet that do not etch

A

borosilicate glass

80
Q

this cuvette is used for acidic solution

A

borosilicate glass

81
Q

cuvette used for basic or alkalin

A

soft glass cuvette

82
Q

Cuvets with ___ on their optical surface scatter light and should be
discarded.

A

scratches

83
Q

Silica cuvettes transmit light effectively at wavelengths ___.

A

220mm

84
Q

Alkaline solutions should not be left standing in cuvets for prolonged
periods because alkali slowly dissolves glass producing etching.

true or false

A

true

85
Q

the path length of cuvets is ___cm, although much smaller path lengths
are used in automated systems.

A

1

86
Q

To increase sensitivity, some cuvets are designed to have path lengths of
___cm, increasing the absorbance for a given solution by a factor of 10.

A

10

87
Q

It detects and converts transmitted light into
photoelectric energy.

A

photodetectors

88
Q

It detects the amount of light that passes through the
sample in the cuvet.

A

photodetector

89
Q

It is the simplest detector; least expensive; temperature-sensitive

A

Barrier layer cell/Photocell/Photovoltaic cell

90
Q

a type of detector used in filter photometers with a wide bandpass

A

Barrier layer cell/Photocell/Photovoltaic cell

91
Q

it is a basic phototransducer that is used for detecting and measuring
radiation in the visible region

A

Barrier layer cell/Photocell/Photovoltaic cell

92
Q

It is composed of selenium on a plate of iron covered with transparent
layer of silver, it requires external voltage source but utilized internal
electron transfer for current production - low internal resistance.

A

Barrier layer cell/Photocell/Photovoltaic cell

93
Q

This cell typically has a maximum sensitivity at about 550 m and the
response falls off to about 10% of the maximum at 350 and 750 nm.

A

Barrier layer cell/Photocell/Photovoltaic cell

94
Q

a photodetector that contains cathode and anode enclosed in a glass case.

A

phototube

95
Q

a photodetector that has a photosensitive material that gives off electron
when light energy strikes it.

A

phototube

96
Q

a photodetector that requires an external voltage for operation

A

phototube

97
Q

the most common photodetector is the - measures visible and UV
regions.

A

photomultiplier tube

98
Q

a detector that has excellent sensitivity and has a rapid response - detects very low
levels of light

A

Photomultiplier tube

99
Q

a photodetector that should never be exposed to a room light because it will burn out.

A

photomultiplier tube

100
Q

a detector that is not as sensitive as PMT but with excellent linearity

A

photodiode

101
Q

a photodetector that measures light at a multitude of wavelengths - detects less
amount of light

A

photodiode

102
Q

a photodetector that has a lower dynamic range and higher noise compared to PMT.

A

photodiode

103
Q

a photodetector that is most useful as a simultaneous multichannel detector

A

photodiode

104
Q

It displays output of the detection system

A

Meter or read-out device

105
Q

example of the read out device

A

galvanometer
ammeter
LED Display

106
Q

a technique that sets the reading to 0 or zero

A

blanking technique

107
Q

means the blank contains serum but without the reagent to
complete the assay.

A

blanking technique

108
Q

corrects absorbance caused by the COLOR OF THE REAGENTS - the
absorbance of reagents is automatically subtracted from each of unknown reading.

A

reagent blank

109
Q

measures absorbance of the sample and reagent in the absence of the
end product, and corrects the measurement for optical interference (like
hemoglobin) absorbing the wavelength of measurement.

A

sample blank

110
Q

a biomolecule that can interfere by increasing light blocked turbidity

A

Lipids

111
Q

turbidity readings on a spectrophotometer are greater in the ____ region than in
the ___region of the spectrum

A

blue; red

112
Q
A