ANALYTICAL METHODS Flashcards

1
Q

Distance between two successive peaks and expressed in terms of nanometer (nm)

A

Wavelength

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2
Q

Infrared region

A

> 700 nm

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3
Q

Visible spectrum

A

400-700 nm

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4
Q

Ultraviolet region

A

<400 nm

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5
Q

Wavelength is ________________ to Frequency and Energy

A

INVERSELY related

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6
Q

Measurement of light intensity in a narrower wavelength

A

Spectrophotometric measurement

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7
Q

Measurement of light intensity

A

Photometric measurement

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8
Q

Involves measurement of light transmitted by a solution to determine the concentration of the light-absorbing substances in the solution

A

Spectrophotometry

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9
Q

Simplest type of absorption spectrometer
Designed to make on measurement at a time at one specified wavelength

A

Single beam spectrophotometer

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10
Q

Instrument that splits the monochromatic light into two components:
1 beam passes through the sample, 1 beam passes through a reference solution or blank

A

Double beam spectrophotometer

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11
Q

Function of additional beam

A

Corrects for variation in light source intensity

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12
Q

Provides polychromatic light and must generate sufficient radiant energy or power to measure the analyte of interest

A

Light or Radiant Source

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13
Q

Emits radiation that changes in intensity;
Widely used in the labroatory

Type of Light source

A

Continuum source

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14
Q

Commonly used light source in the visibule and near infrared region

Example of Continuum source

A

Tungsten light bulb

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15
Q

Routinely used to provide UV radiation

Example of Continuum source

A

Deuterium lamp

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16
Q

Produces a continous source of radiation, which covers both the UV & Visible range

Example of Continuum source

A

Xenon discharge lamp

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17
Q

Emits limited radiation and wavelength

Type of Light Source

A

Line Source

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18
Q

Also used as light sources for spectrophotometry

A

LASER

Light Amplification by Stimulated Emission of Radiation

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19
Q

Tungsten Light Bulb
Mercury Arc

A

Visible Region

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20
Q

Deuterium lamp
Mercury lamp
Xenon lamp
Hydrogen lamp

A

Ultraviolet Region

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21
Q

Merst glower
Globar (Silicone carbide)

A

Infrared Region

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22
Q

Minimizes unwanted or stray light and prevents the entrance of scattered light into the monochromator system

A

Entrance Slit

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23
Q

Any wavelengths outside the band transmitted by the monochromator
Does not originate from the polychromatic light source
Causes Absorbance error

A

Stray light

Most common cause of loss of linearity at high-analyte concentration

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24
Q

Any wavelengths outside the band transmitted by the monochromator
Does not originate from the polychromatic light source
Causes Absorbance error

A

Stray light

Most common cause of loss of linearity at high-analyte concentration

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25
Q

Any wavelengths outside the band transmitted by the monochromator
Does not originate from the polychromatic light source
Causes Absorbance error

A

Stray light

Most common cause of loss of linearity at high-analyte concentration

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26
Q

Isolates specific or individual wavelength of light

A

Monochromator

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27
Q

Most commonly used Monochromator
Made by cutting grooves or slits into an aluminized surface of a flat piece of crown glass

A

Diffraction gratings

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28
Q

Controls the width of light beam
Allows only a narrow fraction of the spectrum to reach the sample cuvette

A

Exit Slit

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29
Q

Holds the solution whose concentration is to be measured

A

Cuvette

Aka Absorption Cell/ Analytical Cell/ Sample Cell

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30
Q

Holds the solution whose concentration is to be measured

A

Cuvette

Aka Absorption Cell/ Analytical Cell/ Sample Cell

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31
Q

Most commonly used cuvette

Can be used in 350-2000 nm

A

Alumina silica glass

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32
Q

Used for measurement of solution requiring visible and ultraviolet spectra

Kinds of Cuvets

A

Quartz/ Plastic

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33
Q

Used for measurement of solution requiring visible and ultraviolet spectra

Kinds of Cuvets

A

Quartz/ Plastic

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34
Q

Detects and converts transmitted light into photoelectric energy Detects the amount of light that passes through the sample in cuvet

A

Photodetector

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35
Q

Simplest detector; Least expensive; Temperature sensitive

Used for detecting and measuring radiation in the visible region

Kinds of Detector

A

Barrier layer cell/ Photocell/ Photovoltaic cell

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36
Q

Contains Cathode and Anode enclosed in a glass case

Kinds of Detector

A

Phototube

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37
Q

Most commonly used detector
Measures visible & UV regions

Kinds of Detector

Should never be exposed to room light because it will burn out

A

Photomultiplier Tube

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38
Q

Not as sensitive as PMT but with excellent linearity
Most useful as a simultaneous multichannel detector

Kinds of Detector

A

Photodiode

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39
Q

Displays output of the detection system

A

Meter or Read-out device

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40
Q

Mathematically establishes the relationship between concentration and absorbance

A

Beer’s Law

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41
Q

Concentration is ____ to Absorbed light

A

DIRECTLY

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42
Q

Concentration is ____ to Transmitted light

A

INVERSELY

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43
Q

Amount of light absorbed

Proportional to the INVERSE log of transmittance

A

Absorbance

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44
Q

Formula of Absorbance

A

A = abc

A = 2-log%T

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45
Q

350 - 430 nm

A

A: Violet
O: Yellow Blue

A for Absorbed, O for Observed

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46
Q

431 - 475 nm

A

A: Blue
O: Yellow

47
Q

476 - 495 nm

A

A: Green-blue
O: Orange

48
Q

496 - 505 nm

A

Blue-green
Red

49
Q

506 - 555 nm

A

Green
Purple

50
Q

556 - 575 nm

A

Yellow-Green
Violet

51
Q

576 - 600 nm

A

Yellow
Blue

52
Q

601 - 650 nm

A

Orange
Green-Blue

53
Q

651 - 700 nm

A

Red
Blue-green

54
Q

Blank contains serum but without the reagent to complete the assay

A

Blanking technique

55
Q

Corrects absorbance caused by the color of the reagent

A

Reagent blank

56
Q

Measures absorbance of the sample and reagent in the absence of the endproduct

A

Sample Blank

57
Q

Measures the light emitted by a single atom burned in a flame
Excitation of elevtrons from LOWER to HIGHER energy state

A

Flame Emission Photometry

Measurement of excited ions: Na & K

58
Q

Measures the light absorbed by atoms dissociated by heat
More sensitive than FEP

A

Atomic Absorption Spectrophotometry (AAS)

Measurement of unexcited trace metals: Ca & Mg

59
Q

Unknown sample is made to react with a known solution in presence of an indicator

A

Volumetric or Titrimetric

60
Q

Schales and Schales method

Example of Volumetric

A

Chloride test

61
Q

EDTA Titration method

Example of Volumetric

A

Calcium test

62
Q

Measuring large particles and bacterial suspensions
Determines amount of light BLOCKED by a particulate matter

A

Turbidimetry

Depends on specimen concentration and particle size

63
Q

Measuring amount of antigen-antibody complexes
Determines amount of SCATTERED light by a particulate matter

A

Nephelometry

Depens on wavelength and particle size

64
Q

Measuring amount of antigen-antibody complexes
Determines amount of SCATTERED light by a particulate matter

A

Nephelometry

Depens on wavelength and particle size

65
Q

Migration of charged particles in an electric field
Separates protein on the basis of their electric charge densities

A

Electrophoresis

Protein are negatively vharged (anions) and move towards the anode

66
Q

Has a net charge that can be either positive or negative depending on pH conditions

A

Amphoteric

67
Q

Migration of small charged ions

A

Iontophoresis

68
Q

Migration of charged MACROmolecules

A

Zone Electrophoresis

69
Q

Factors affecting rate of Migration

A
  1. Net electric charge
  2. Size and Shape
  3. Electric field strength
  4. Nature of supporting medium
  5. Temperature
70
Q

Separates by molecular size

type of supporting media

A

Cellulose Acetate

71
Q

Separates by electrical charge
Does not bind protein

type of supporting media

A

Agarose gel

72
Q

Separates on basis of charge and molecular size
Separates porteins into 20 fracrions
Used to study Isoenzymes

type of supporting media

A

Polyacrylamide gel

73
Q

Stains for Visualization of Fractions

A
  1. Amido black
  2. Ponceau S
  3. Oil Red O
  4. Sudan black
  5. Fat Red 7B
  6. Coomassie Blue
  7. Gold/ Silver stain
74
Q

Measures the absorbance of stain - concentration of the dye and protein fraction

A

Densitometer

75
Q

Electrophoretic mobility is ____ to Net charge

A

Directly proportional

76
Q

Electrophoretic mobility is ——- to molecular size and viscosity of supporting medium

A

Inversely Proportional

77
Q

Separates molecules by migration through a pH gradient
Ideal for separating proteins of identical sizes but with different net charges

A

Isoelectric Focusing

pH = pI

78
Q

Advantages of Isoelectric focusing

A
  1. Ability to resolve mixture of proteins
  2. Detect isoenzymes of ACP, CK and ALP
  3. Identify genetic variants of proteins such as alpha-1-antitrypsin
  4. Detect CSF oligoclonal banding
79
Q

Sample molecules are separated by electro-osmotic flow
(+) charged emerge early at the capillary outlet
(-) charged move towards the capillary outlet but at slower rate

A

Capillary Electrophoresis

80
Q

Southern blot

A

DNA

81
Q

Northern blot

A

RNA

82
Q

Western blot

A

Proteins

83
Q

Involves the separation of soluble components by specific differences in physical-chemical characteristics of the different constituents

A

Chromatography

84
Q

Used for fractionation of sugar and amino acid

A

Paper Chromatography

85
Q

Sorbent or Stationary phase in Paper chromatography

A

Whatman paper

86
Q

Semiquantitative drug screening test
Sample components are identified by comparison with standards on the same plate

A

Thin Layer Chromatography

87
Q

Sorbent in TLC

A

Thin plastic plates impregnated with a layer of silica gel or alumina

88
Q

Rf value formula

A

Rf = distance leading edge of component moves/ total distance

89
Q

Separation of steroid, barbiturates, blood, alcohol and lipids
Useful in compounds that are naturally volatile or can be easily converted into a volatile form

A

Gas Chromatography

90
Q

Based on the fragmentation and ionization of molecules using a suitable source of energy
Detects structural information and determination of molecular weight

A

Mass Spectroscopy

91
Q

Gold Standard for drug testing
Also used for xenobiotics, anabolic steroids and pesticides

A

Gas Chromatography-Mass Spectroscopy (GC-MS)

Every drug has its own fingerprint pattern

92
Q

Can detect 20 inborn errors of metabolism from a single blood spot

A

Tandem Mass Spectroscopy (MS/MS)

93
Q

Most widely used liquid chromatography
Fractionation of drugs, hormones, lipids, carbohydrates and proteins

Uses pressure for fast separations, controlled temp, in-line detectors

A

High Performace Liquid Chromatography (HPLC)

94
Q

Detecting nonvolatile substances in body fluids
Confirm positive results from screening of illicited drugs
Used in TDM, Toxicology & studies of drug metabolites

A

Liquid Chromatography - Mass Spectroscopy (LC/MS)

95
Q

Gel filtration
Separation of enzymes, antibodies and proteins

Dextran & Agarose

A

Hydrophilic gel

96
Q

Gel permeation
Separation of triglyceride & fatty acids

Sephadex

A

Hydrophobic gel

97
Q

Exchange of sample ions and mobile phase ions with the charged group of the stationary phase

A

Ion Exchange Chromatography

Separation of AA, CHON & NA

98
Q

Separation of compounds based on their partition between a liquid mobile phase and a liquid stationaty phase

Separation of TDM and their metabolite

A

Partition Chromatography

99
Q

Uses the so-called lock-and-key binding

Separation of lipoproteins, CHO, and glycated hemoglobins & Antibodies

A

Affinity Chromatography

100
Q

Based on differences between the adsorption and desroption of solutes at the surface of a solid particel

A

Adsorption Chromatography

101
Q

Measures the amount of light intensity present over a zero background
Determines the amount of light emitted by a molecule after excitation by electromagnetic radiation

1000x more sensitive than Spectrometry

A

Fluorometry/
Molecular Luminescence Spectrophotometry

102
Q

Major disadvantage of Fluorometry
pH and temperature changes, chemical contaminants and UVL changes

A

Quenching

103
Q

Differs from fluorescence and phosphorescence in that the emission of light is created from a chemical or electrochemical reaction and not from absorption of electromagnetic energy

More sensitive than fluorescence

A

Chemiluminescence

104
Q

Measurement of osmolality of an aqueous solution
Based on measuring changes in colligative properties

A

Osmometry

105
Q

Osmolality is ___ to Osmotic pressure and boiling point

A

DIRECTLY Proportional

106
Q

Osmolality is ____ to Freezing point and Vapor Pressure

A

INVERSELY Proportional

More commonly used: Freezing point

107
Q

Most commonly used method for measuring the changes in colligative properties of a solution
Addition of solute molecules LOWERS the temperature at which a solution freezes

A

Freezing-point depression osmometry

108
Q

Measurement of electrical potential due to the activity of free ions
Measurement of differences in voltage at a constant current
Follows the Nernst Equation

A

Potentiometry

Use pH and pCO2

109
Q

Reference Electrodes in potentiometry

A

Calomel &Silver-Silver Chloride

110
Q

Electrochemical transducer capable of responding to one given ion
Very sensitive and selective for the ion it measures

A

Ion Selective Electrode

111
Q

Measurement of amount of electricity at a fixed potential
Follows the Faraday’s law
Use: Chloride test

A

Coulometry

112
Q

Measurement of the current flow produced by an oxidation-reaction

A

Amperometry

Use: pO2, Glucose, Chloride, Peroxidase

113
Q

Measurement of current after which a potential is applied to an electrochemical cell

A

Voltammetry