Analytical Techniques

Question 1

Wavelength for Visible light

Answer 1

400-700 nm

Question 2

It takes advantage of the property of colored
solutions to absorb light of specific wavelengths.

Answer 2

Spectrophotometry

Question 3

Provide incident light for the system

Answer 3

Light source

Question 4

• For visible and near infrared
  region spectrum
• Commonly used in the
  laboratory

Answer 4

Incandescent tungsten or tungsten iodide lamp

Question 5

Minimizes the unwanted or stray light and
prevents the entry of scattered light in the
monochromator system

Answer 5

Entrance Slit

Question 6

Isolates a specific wavelength from the light
source

Answer 6

Monochromator

Question 7

• Controls the width of the light beam
• Could only allow a narrow fraction of spectrum to
  pass through and reach the sample cuvette

Answer 7

Exit slit

Question 8

• Also known as cuvette or analytical cell
• Holds the solution of which the absorption is to be
  measured

Answer 8

Sample cell/Cuvette

Question 9

Converts transmitted radiant energy into an
equivalent amount of electrical energy

Answer 9

Photodetector

Question 10

Most common type of
photodetector used in
spectrophotometer because it
could measure visible and UV
region

Answer 10

Photomultiplier tube

Question 11

• Has a beam splitter that splits the
  monochromatic light into two
  components
  ○ First component goes to the
  patient sample cell.
  ○ Second component goes to the
  standard material or reference
  cell.

Answer 11

Double-beam spectrophotometer

Question 12

Measures light emitted by excited atoms
- Used to measure sodium, potassium and
lithium because the are easy to excite

Answer 12

Flame Emission Spectrophotometry (FES)

Question 13

Principle of FES

Answer 13

Flame using propane is used to excite
the atoms (higher energy state)

Question 14

It is used to correct the variation in flame and atomizer characteristics

Answer 14

Internal Standard

Question 15

Internal standard for Lithium

Answer 15

Cesium

Question 16

Internal standard for Lithium

Answer 16

Cesium

Question 17

• Measures light absorbed by ground state atoms
• Used to measure concentration of calcium atom
  (not easily excited) - Calcium, Magnetium
• 100 tiimes more sensitive than FES
• REFERENCE METHOD for Calcium and
  Magnesium

Answer 17

Atomic Absorption Spectrophotometry (AAS)

Question 18

The light source used for AAS

Answer 18

Hallow Cathode Lamp (or Electrodeless discharge lamp)

Question 19

Measures the intensity of emitted light
when an activated atom returns to the ground state

Answer 19

Atomic Emission

Question 20

Measures the absorption of light by atoms in the ground states

Answer 20

Atomic Absorption

Question 21

Principle: Energy emission that occurs when
certain compounds absorb electromagnetic radiation, becomes excited gives of light

Answer 21

Fluorometry

Question 22

Light source for Fluorometer

Answer 22

Mercury-vapor lights or Xenon-Arc lamp

Question 23

Process of exciting molecules by
chemical means and measuring the light
emitted as the molecules return to their
stable unexcited state

Answer 23

Chemiluminescence

Question 24

Process of exciting molecules by
chemical means and measuring the light
emitted as the molecules return to their
stable unexcited state

Answer 24

Chemiluminescence

Question 25

Priniciple: Measures the amount of light blocked (absorbance) by suspension of particles (insoluble particles)

Answer 25

Turbidimetry

Question 26

Light scattered by the small particles is measured at an angle (forward or 90 degrees) to the incident light Application: Atntibody-antigen reaction

Answer 26

Nephelometry