ANALYTICAL METHODS AND INSTRUMENTATION part 2

Question 1

• when atoms return to the ground state, they emit radiation which lies mainly in the visible region of the spectrum

Answer 1

. FLAME PHOTOMETRY

Question 2

• each element will emit radiation at a wavelength specific for that element
• based on the characteristic emission of light by analytes (low oxidation states) which are easily excited when exposed to sufficient

Answer 2

FLAME PHOTOMETRY

Question 3

• Rule: light intensity = the ________ of atoms = ________ of analyte

Answer 3

number
concentration

Question 4

serves as the LIGHT SOURCE and CUVETTE

Answer 4

FLAME

Question 5

• measures light absorbed by atoms at a ground state which is reflective of the concentration of the atom
• intended for analytes which are not easily excited by the flame

Answer 5

. ATOMIC ABSORPTION SPECTROPHOTOMETRY

Question 6

unexcited state of atoms

Answer 6

• ground state

Question 7

it is used principally for the quantitative determination of metal elements in aqueous and solid samples

Answer 7

ATOMIC ABSORPTION SPECTROPHOTOMETRY

Question 8

What is the light source of AAS?

Answer 8

Hollow-cathode lamp

Question 9

measures light scattered

Answer 9

NEPHELOMETRY

Question 10

detector is at 90’ or 30’ angle from the incident light

Answer 10

NEPHELOMETRY

Question 11

detection of light scattered or reflected toward a detector that is not in the direct path of transmitted light

Answer 11

NEPHELOMETRY

Question 12

some nephelometers are designed to measure scattered light at an angle other than 90’ to take advantage of the __________ -scatter intensity caused by light scattering from large particles

Answer 12

increased forward scatter

Question 13

excitation and detection wavelengths of a nephelometer will be set to the _______

Answer 13

same value

Question 14

• measures light blocked by particles/ reduced by a particle in the solution
• amount of light reduced is measured at 180’
• dependent on the size of particle and wavelength
• detector in line with the incident light thus, decrease in transmission
• the higher the concentration, the lower the transmittance (greater the amount of light blocked)

Answer 14

TURBIDIMETRY

Question 15

used to measure the intensity of light scattering

Answer 15

turbidimeter

Question 16

Applications
- microbiology
- hematology

Answer 16

. TURBIDIMETRY

Question 17

• reaction of unknown with an indicator
• examples: Schales and Schales method (Chloride); EDTA Titration method (Calcium)

Answer 17

VOLUMTERY/ TITRIMETRY

Question 18

• it measures the electrical potential from the activity of free ions
• also measures the difference in voltage at a constant current

Answer 18

POTENTIOMETRY

Question 19

• it measures the difference in current at a constant voltage

Answer 19

. POLAROGRAPHY

Question 20

• measures the amount of electricity at a fixed potential

Answer 20

COULOMETRY

Question 21

it measures the current flow produced during redox reactions

Answer 21

AMPEROMETRY

Question 22

separation of molecules according to their density once there is an application of an electric current

Answer 22

ELECTROPHORESIS

Question 23

migration of charged solutes or particles in an electric field

Answer 23

ELECTROPHORESIS

Question 24

consists of 5 components:
- electrical power
- supporting medium: can be cellulose acetate, agarose gel, starch gel, or polyacrylamide gel
- buffer
- sample
- detecting system

Answer 24

ELECTROPHORESIS

Question 25

mixtures are separated, identified and determined according to their movement in the stationary phase - consist of: - mobile phase - stationary phase

Answer 25

CHROMATOGRAPHY

Question 26

Chromatography may be ______________ or ___________.

Answer 26

Planar or columnar

Question 27

- clinically used for urine drug test screening

Answer 27

Thin Layer

Question 28

used to separate volatile solutes

Answer 28

Gas-liquid

Question 29

- uses pressure for fast separation - used to separate hemoglobin, lipids, and drugs

Answer 29

High Performance Liquid

Question 30

used for the separation of amino acids, proteins, and nucleic acids

Answer 30

Ion Exchange

Question 31

used to separate lipoproteins, carbohydrates, and antibodies

Answer 31

Affinity

Question 32

- the chemical reaction yields an electronically excited compound that emits light as it returns to its ground state, or that transfers its energy to another compound, which then produces emission.

Answer 32

CHEMILUMINESCENCE

Question 33

light is emitted from the excited product formed in the oxidation reaction - does not use a light source - Does not require a monochromator - requires a photodetector

Answer 33

CHEMILUMINESCENCE

Question 34

measures light in chemiluminescence

Answer 34

Luminometer

Question 35

Limitations of Chemiluminescence: 1. Light ___________ 2. Light ___________ 3. High background________from assay reagents and reaction vessels 4. Very high ___________

Answer 35

leaks piping luminescence intensity emission