Spectrophotometer Flashcards

1
Q

measurement of light intensity in a much
narrower wavelength.

A

Spectrophotometry

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2
Q

It uses a device
(prisms and/or gratings) to disperse the
source of light into a continuous spectrum.

A

Spectrophotometry

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3
Q

2 Dispersing element or monochromator

A

prism (triangle) and grating

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4
Q

Basic component device

A

Light source
Entrance slit
Dispersive elements
Exit slit
Sample
Detector

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5
Q

Basic
Components

A

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

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6
Q

Different light sources

A

Continuum source

Line source

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7
Q

emits radiation that changes in
intensity/ Immites radiation wide source

A

Continuum source

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8
Q

type of light Source

A

Tungsten iodine lamp
Quartz halide lamp
Deuterium discharge lamp
Infrared energy source

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9
Q

Most commonly used light source

A

Tungsten iodine lamp

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10
Q

contains small amounts of
halogen such as iodine to prevent the decomposition
of the vaporized tungsten from the very hot filament.

A

Quartz halide lamp

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11
Q

provides energy source
with high output in the UV range (down to 165 nm).

A

Deuterium discharge lamp

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12
Q

used above 800 nm.

A

Infrared energy lamp

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13
Q

It is a device more sophisticated it isolates the narrow band of wavelengths from visible and ultraviolet sources

A

Monochromator

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14
Q

monochromator is made up of three parts:

A

Entrance slit
Dispersive elements
Exit slit

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15
Q

is a small circular or rectangular hole cut in an otherwise opaque plate,
such as a black metal plate.

A

Slit

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16
Q

is where light enters the monochromator from the source. Its
purpose is to create a unidirectional beam of light of appropriate intensity
from the multidirectional light emanating from the source

A

Entrance Slit

17
Q

After passing through the entrance slit, the beam
encounters a ______________

A

Disperse element

18
Q

The narrow band of the spectrum is then selected by the ______________

19
Q

is rotated, the spray of colors moves
across the exit slit such that a different narrow wavelength range
emerges from the exit slit at each position of rotation.

A

Disperse element

20
Q

is a three-dimensional triangularly shaped glass or quartz
block. When the light beam strikes one of the three faces of the
prism, the light emerging through another face is dispersed.

21
Q

is like a highly polished mirror that has a large
number of precisely parallel lines or grooves scribed onto its
surface. Light striking this surface is reflected, diffracted, and
dispersed into the component wavelengths-

A

Diffraction grating

22
Q

Type of Detectors:

A

Photomultiplier and photodiodes

23
Q

are
used as detectors in UV-VIS
spectrophotometers

A

Photomultiplier tubes or
photodiodes (light sensors)

24
Q

is a light sensor combined with
a signal amplifier. The light emerging from the sample
compartment strikes the photosensitive surface and
the resulting electrical signal is amplified.

A

Photomultiplier

25
The photomultiplier tube consists of a
Photocathode, anode, and dynodes
26
This amplified signal is then sent on to the readout
Photomultiplier
27
Photodiodes Utilizes materials such as
Silicon
28
Silicon can be doped with impurities to make it either electron rich
BORAN n- type semiconductor
29
electron poor
p-type semiconductor
30
used for UV-VIS spectrophotometry must be transparent to all wavelengths of light for which it is use
Cuvette
31
If visible light is used, the material must ideally be completely clear and colorless, which means that inexpensive materials, such as
Colorless glass or plastic
32
For visible light spectrophotometry, the cuvettes must be made of
Colorless glass or plastic
33
For ultraviolet spectrophotometry, the cuvettes must be made of
Quartz
34
Warm Up spectrophotometry
20 mins
35
is a contaminating substance that gives an absorbance signal at the same wavelength or wavelength range selected for the analyte.
Interference
36
- can be high or low because of it
Interference