Analytical Methods Flashcards

1
Q

principle: measurement of light transmitted by solution to determine concentration of light-absorbing substances in solution

identify the analytical method

A

spectrophotometry

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2
Q

describe double beam spectrophotometer. how does it work?

A

monochromatic light split into two components. absorbance of sample can be recorded directly

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3
Q

State Beer’s Law

A

concentration of a substance is directly proportional to the light absorbed, or inversely proportional to the logarithm of transmitted light

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4
Q

purpose of collimator @ spectrophotometer

A

minimizes unwanted/scattered light

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5
Q

purpose of monochromator @ spectrophotometer

A

wavelength selector

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6
Q

T/F

Glass cuvette is used for both visible and UV light

A

F

quartz: UV radiation

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7
Q

identify:

convert transmitted radiant energy into equiv amt of electrical energy

A

photodetector

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8
Q

Amount of light absorbed at wavelength depends on molecular and ion types. Which 3 factors may affect?

A

concentration
pH
temperature

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9
Q

Differentiate reagent blank fr sample blank

A

reagent blank: corrects absorbance caused by color of reagent
sample blank: corrects absorbance caused by optical interference

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10
Q

identify instrument: measures absorption of light of unique wavelength by atoms @ ground state

A

atomic absorption spectrophotometer

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11
Q

Light source for Atomic absorption spectrophotometer

A

Hollow cathode lamp

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12
Q
Which modulates light source @ atomic  absorption spectrophotometer?
A. Chopper
B. Nebulizer
C. Both A and B
D. NOTA
A

A

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13
Q
Which converts ions @ atomic  absorption spectrophotometer?
A. Chopper
B. Nebulizer
C. Both A and B
D. NOTA
A

B

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14
Q
atomic  absorption spectrophotometer applied at the ff except-
A. Electrolytes
B. Dissolved gases
C. Carboxylic Acids
D. NOTA
A

C

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15
Q

Before mass spectrometry, the compound must be isolated via gas chrom/HPLC.

True or false?

A

True

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16
Q
Mass spectrometry is used in:
A. Drug testing
B. Proteomics
C. Both A and B
D.NOTA
A

C

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17
Q

Identify analytical method

Measures amt of light emitted by a molecule after excitation by EM radiation

A

Fluorometry

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18
Q

[Fluorometry]

Purpose of primary filter @ monochromator

A

Allow passage of light of the proper wavelength for absorption of molecule

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19
Q
Factors that affect fluorescence include all except
A. pH changes
B. Temperature
C. Exposure duration
D. Hue of substance
A

D

Concentration dapat

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20
Q

False about chemiluminescence
A. Frm species
B. Emitted radiation is related to analyte concentration
C. Chemical rxn: electronically excited cpd that emits light as it returns to ground state
D. Signal is taken as derivative of entire peak

A

D

integral dapat

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21
Q

Main disadvantage of chemiluminescence

A

Impurities can cause background signal that degrades sensitivity and specificity

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22
Q

Identify analytical method.

Measurement of light scattered by particulate (turbid solution). Light has signal that must be amplified

A

Nephelometry

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23
Q
[Nephelometry]
Light scattering dep on all except
A.wavelength of incident light 
B.particle size
C.amount of sample
A

C

24
Q

[Nephelometry]

wavelength of incident light __ particle diam, para at least forward

A

less than or equal to

25
Q

[Nephelometry]

Main application

A

measurement of Ag-Ab complex

26
Q

[Nephelometry]

Identify type: wavelengths use are 320-650nm. Light scattered forward

A

Rayleigh-Debye type

27
Q

[Nephelometry]
T/F
Detector output is inversely prop to concentration

A

F

Direct prop dapat

28
Q

Measures reduction in light transmission due to particle formation

Identify analytical method

A

[Turbidimetry]

29
Q

[Turbidimetry]

Amount of light absorbed by a suspension of particles depends on two factors: __ & __

A

Specimen conc

Particle size

30
Q
Turbidimetry may be applied in all except
A. Glucose measurement of CSF
B. Detect bacterial growth in broth
C. Detect clot formation
D. Protein measurement in urine
A

A

31
Q

[Electrophoresis]

The ff affect rate of migration except
A. Shape of molecule
B. Electric field strength
C. Nature of supporting medium
D. Pressure applied to machine
A

D

Temp dapat

32
Q

[Electrophoresis]

The ff separate by molecular size except
A.Starch gel
B.Agarose gel
C.Polyacrylamide gel

A

B

33
Q

[Electrophoresis]

Which supp medium does not bind protein?
A.Starch gel
B.Agarose gel
C.Polyacrylamide gel

A

B

34
Q

Identify the analytical method:

charged proteins migrate through support medium that has continuous pH gradient

A

isoelectric focusing

35
Q

isoelectric focusing: applied in two ways. enumerate

A
  1. detect oligoclonal immunoglobulin bands in CSF

2. detect enzymes like ALP in serum

36
Q

identify instrument:

measures absorbance of the stain on a support medium

A

densitometer

37
Q

[Densitometry]

Signals detected by photodetector: related to absorbance of sample stain on the support. This is proportional to ___

A

specimen concentration

38
Q

identify analytical method:

measurement of electrical potential due to activity of free ions, or differences in voltage at constant currrent

A

potentiometry

39
Q

[potentiometry]

activity of analyte indicated in __

A

change in voltage

40
Q

[potentiometry]

applied in: __ and __

A

electrolytes

Dissolved gases

41
Q

identify analytical method:

measurement of the current flow produced by redox reaction

A

amperometry

42
Q

identify analytical method:

method in which potential is applied to electrochemical cell, and resulting current is measured

A

voltametry

43
Q

identify analytical method:

measurement of quantity of electricity needed to convert analyte to diff oxid state.

A

coulometry

44
Q

coulometry: direct application?

A

used to measure chloride ion in serum, plasma, CSF & sweat samples

45
Q

identify analytical method:
separation method based on diff interactions of specimen compounds with mobile phase and stationary phase, as compounds travel thru support medium

A

chromatography

46
Q

chromatography methods useful for compounds that are naturally inclined to be volatile; used in separation of blood, alcohol, lipids

A

gas chromatography

47
Q

Gel chromatography separates molecules based on size and shape. It may use hydrophilic gel or hydrophobic gel. Uses of the former?

A

hydrophilic gel: sep antibodies, enzymes, proteins

48
Q

Gel chromatography separates molecules based on size and shape. It may use hydrophilic gel or hydrophobic gel. Uses of the latter?

A

hydrophobic gel: sep triglycerides, fatty acids

49
Q

identify chrom method

exchange of sample ions and mobile-phase ions with charged grp of stationary phase

A

ion exchange chromatography

50
Q

identify chrom method

separation of compounds is based on partition bet liquid mobile phase and liq stationary phase, coated on solid support

A

partition chromatography

51
Q

identify chrom method

uses immobilized biochem ligands as stationary phase to separate a few solutes fr other unretained solutes

A

affinity chromatography

52
Q

identify chrom method

separation based on absorption/desorption of solutes @ surface of solid particle

A

adsorption chromatography

53
Q
affinity chromatography may separate all except
A. lipoproteins
B. carbohydrates
C. glycated hemoglobins
D. vitamins
A

D

54
Q

Enumerate 4 types of analytic errors

A

random
systematic
total
idiosyncratic

55
Q

Enumerate 4 advantages of automating lab testing

A
  1. eliminate repetitive stress injury
  2. less error rates
  3. reduce operator occup hazard
  4. increase quality of pre-analytic steps
56
Q

Enumerate 3 sources of problems, in sample introduction @ analytic stage

A

a. formation of clot attached to probe
b. inadequate or short sample
c. carry over