ANALYTICAL METHODS [SPECTROPHOTOMETER PARTS] Flashcards

1
Q

What are the 6 basic components of single or double-beam configuration spectrophotmeter.

A
  1. Stable Light Source
  2. Filter
  3. Sample Holder
  4. Radiation Detector
  5. Signal Processor
  6. Readout Device
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2
Q

This component of a spectrophotometer isolates a specific region of the electromagnetic spectrum.

A

Filter

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3
Q

What are the parts of a spectrophotometer?

A
  1. Light or Radiant Source
  2. Entrance Slit
  3. Monochromator
  4. Exit Slit
  5. Cuvette
  6. Photodetector
  7. Meter or Read-out Device
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4
Q

This provides polychromatic light in order to measure the analyte of interest.

A

Light or Radiant Source

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5
Q

What are the two types of light sources.

A

Continuum and Line Source

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6
Q

This radiant source emits radiation that changes in intensity; widely used in the laboratory.

A

Continuum Source

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7
Q

These are examples of a continuum source.

A

Tungsten, Deuterium, Xenon Lamps/Bulbs

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8
Q

This radiant source is limited in both radiation and wavelength.

A

Line Source

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9
Q

This radiant source is used in atomic, molecular, and fluorescent spectroscopy.

A

Line Source

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10
Q

What is the meaning of LASER?

A

Light Amplification via Stimulated Emission of Radiation

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11
Q

What are the examples of line sources?

A

Mercury and Sodium Vapor, and Hollow Cathode Lamp.

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12
Q

What regions does the Hg and Na vapor lamps filter?

A

UV and Visible Regions

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13
Q

What specific technique utilizes Hollow Cathode Lamps as their radiant source?

A

Atomic Absorption Spectrophotometry

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14
Q

What are the factors needed in changing a light source.

A
  1. Range
  2. Spectral Distribution
  3. Light Production
  4. Stability of Light
  5. Temperature
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15
Q

What are radiant sources suitable for both the visible and UV region?

A

Mercury Arc

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16
Q

What are radiant sources suitable for the UV region?

A

Deuterium, Hydrogen, and Xenon Lamps

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17
Q

What are radiant sources suitable for the IR region?

A

Merst Glower and Globar

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18
Q

This part minimizes the unwanted or stray light to prevent scattered light into the monochromator.

A

Entrance Slit

19
Q

What are the 5 characteristics of stray light?

A
  1. Any wavelenth outside the monochromator.
  2. Does not originate from radiant source.
  3. Causes absorbance error.
  4. Limints maximum absorbance.
  5. Most common cause of loss of linearity at high analyte concentration.
20
Q

This part isolates specific or individual wavelength of light.

A

Monochromator

21
Q

What are the kinds of monochromators?

A
  1. Prisms
  2. Diffraction Gratings
  3. Filters
  4. Holographic Gratings
22
Q

A wedge-shaped piece of glass made of quarts or NaCl; rotatable to allow desired wavelength.

A

Prisms

23
Q

Most commonly used monochromator kind that is better than a prism.

Made with grooves or slits into an auminized surface of a flat crown glass.

A

Diffraction Gratings

24
Q

This is a simple kind of monochromator that is useful yet imprecise, made of silver films like MgF2, and produces monochromatic light.

Monochromatic light is based on the principle of contstructive interference of waves.

A

Filters

25
Q

This monochromator is a type of diffraction grating that is formed by an interference-fringe field.

Two laser beams exposed to a polished substrate coated with photoresist.

A

Holographic Gratings

26
Q

This part of a spectrophotometer holds the solution needed to be measured.

A

Cuvette

27
Q

Other words for the cuvette.

A

Absorption, Analytical, or Sample Cell

28
Q

What are the different kinds of cuvettes?

A
  1. Alumina Silica Glass
  2. Quatz Plastic
  3. Borosilicate Glass
  4. Soft Glass
29
Q

This part detects and coverts transmitted light into photoelectric energy.

Detects the amount of light that passe through the sample in the cuvet.

A

Photodetector

30
Q

What are the kinds of photodetectors?

A
  1. Barrier Layer Cell
  2. Phototube
  3. Photomultipier Tube
  4. Photodiodide
31
Q

This is the simplest, least espensive, temperature sensitive photdetector.

A

Barrier Layer Cell

Also called the Photocell or Photovoltaic Cell

32
Q

This photodetector is used for detecting and measuring radiation in the visible region.

A

Barrier Layer Cell

33
Q

What is the barrier layer cell composed of?

A

Selenium, Iron Plate, and Silver

Selenium on a plate of iron covered with a layer of silver.

34
Q

Barrier layer cells requires no external voltage but needs (?).

A

Internal Electron Transfer

35
Q

What is the maximum sensitivity of a barrier layer cell?

A

Maximum of 550nm then falls of to 350nm to 750nm.

36
Q

This photoreceptor is used in filter photometry with a wide bandpass.

A

Barrier Layer Cell

37
Q

This photoreceptor contains a cathode and an anode enclosed in glass. When light strikes it, it gives off electrons.

A

Phototube

38
Q

True or False: Phototubes requires no external voltage, only electron tranfer.

A

False, it requires external voltage only.

39
Q

This photoreceptor is commonly used for visible and UV regions, has excellent sensitivity, rapid respone, and detects low levels of light.

A

Photomultiplier Tube

40
Q

True or False: It is best to use a photomultiplier tube at a well lit room in order to maxmize its detection capacity.

A

False, photomultipier tubes should never be exposed to room light, otherwise it will burn out.

41
Q

This photoreceptor has excellent linearity, multitude of wavelengths, and is most useful as a multichannel detector.

A

Photoiodide

42
Q

This photoreceptor is less sensitive, lower range, higher noise, and detects less amounts of light than a PM tube.

A

Photoiodide

43
Q

This part displays the output of the detection system of a spectrophotometer.

A

Meter or Read-out Device

44
Q

These are examples of read-out devices.

A
  1. Galvanometer
  2. Ammeter
  3. LED Display