Analytical Methods and Instrumentation Flashcards
____ provide the foundation for all measurements made in a modern clinical chemistry laboratory.
Analytic Techniques and Instrumentation
Four Basic Disciplines
- Spectrometry
- Luminescence
- Electroanalytic Methods
- Chromatography
Methods under Spectrometry
- Spectrophotometry
- Atomic Absoption Spectrometry (AAS)
- Mass Spectrometry (MS)
Methods under Luminescence
- Fluorescence
- Chemiluminescence
Methods under Electroanalytic Methods
- Electrophoresis
- Potentiometry/Amperometry
Methods under Chromatography
- Gas
- Liquid
- Thin-layer
Other Analytical Methods
- Colorimetry
- Volumetric (Titrimetric)
- Turbidimetry
- Nephelometry
- Fluorometry
- Osmometry
- Electrochemistry Techniques
The primary goal of ____ is the isolation of discreet portions of the sprectrum.
Photocolorimetry
Photocolorimetry is used for measuring ____ in the laboratory.
analytes
Measurements under Photocolorimetry
- Spectrophotometric measurement
- Photometric measurement
____ is the measurement of light intensity in a narrower wavelength.
Spectrophotometric measurement
____ is the measurement of light intensity without consideration of the wavelength.
Photometric measurement
____ involves the measurement of the light transmitted by a solution to determine the concentration of the light-absorbing substance.
Spectrophotometry
Two Types of Spectrophotometer
- Single Beam
- Double Beam
____ is the simplest type of spectrophotometer.
Single Beam Spectrophotometer
____ is designed to make one measurement at a time at one specified wavelength.
Single Beam Spectrophotometer
In ____, the absorpition maximum of the analyte must be known in advanced.
Single Beam Photometer
In single beam spectrophotometer, the ____ must be known in advanced.
maximum absorption
____ splits the monochromatic light into two components.
Double Beam Spectrophotometer
In ____, one beam passes throughout the sample and the other beam passes through reference solution or reagent blank.
Double Beam Spectrophotomer
What is the purpose of the additional beam in Double Beam Spectrophotometer?
To correct for variation of light source intensity
In double beam spectrophotometry, absorbance of the sample can be recorded directly as the ____ of the sample beam.
electrical output
2 Types of Double Beam Spectrophotometer
- Double-beam in space
- Double-beam in time
____ uses two photodetectors for the sample and reference beam.
Double-beam in space spectrophotometer
Using ____, the beam is split into two paths and measured by matched detectors.
double-beam in space spectrophotometer
____ uses one photodetector, and alternately passes the monochromatic light using a chopper or rotating sector minor.
Double-beam in time spectrophotometer
Double-beam in time spectrophotometer uses a ____ to alternately pass the monochromatic light through the sample cuvette and reference cuvette.
chopper or rotating sector minor
Using ____, the beam is split into two but is measured by the same detector.
double-beam in time spectrophotometer
6 Basic Components of Single or Double-Beam Configuration Spectrophotometer
- Stable source of radiant energy
- Filter
- Sample holder
- Radiation detector
- Signal processor
- Readout device
____ isolates the specific region of the EFS.
Filter
____ is also called “photomultiplier”.
Radiation detector
Visible light travels at a speed of ____.
300,000 km/s
Visible light can be broken down into ____ colors.
7
Colors of the visible spectrum
- Red
- Orange
- Yellow
- Green
- Blue
- Indigo
- Violet
Visible spectrum range
350 nm - 700 nm
Colors and the Complementary Colors of the Visible Spectrum
Wavelength: 350-430
Color Absorbed:
Complementary Color: Yellow - Blue
Violet
Colors and the Complementary Colors of the Visible Spectrum
Wavelength: 350-430
Color Absorbed: Violet
Complementary Color:
Yellow - Blue
Colors and the Complementary Colors of the Visible Spectrum
Wavelength:
Color Absorbed: Violet
Complementary Color: Yellow - Blue
350 - 430
Colors and the Complementary Colors of the Visible Spectrum
Wavelength: 431-475
Color Absorbed:
Complementary Color: Yellow
Blue
Colors and the Complementary Colors of the Visible Spectrum
Wavelength: 431-475
Color Absorbed: Blue
Complementary Color:
Yellow
Colors and the Complementary Colors of the Visible Spectrum
Wavelength:
Color Absorbed: Blue
Complementary Color: Yellow
431 - 475
Colors and the Complementary Colors of the Visible Spectrum
Wavelength: 476-495
Color Absorbed:
Complementary Color: Orange
Green - blue
Colors and the Complementary Colors of the Visible Spectrum
Wavelength: 476-495
Color Absorbed: Green-blue
Complementary Color:
Orange
Colors and the Complementary Colors of the Visible Spectrum
Wavelength:
Color Absorbed: Green-blue
Complementary Color: Orange
476 - 495
Colors and the Complementary Colors of the Visible Spectrum
Wavelength: 496-505
Color Absorbed:
Complementary Color: Red
Blue - green
Colors and the Complementary Colors of the Visible Spectrum
Wavelength: 496-505
Color Absorbed: Blue-green
Complementary Color:
Red
Colors and the Complementary Colors of the Visible Spectrum
Wavelength:
Color Absorbed: Blue-green
Complementary Color: Red
496 - 505
Colors and the Complementary Colors of the Visible Spectrum
Wavelength: 506-555
Color Absorbed:
Complementary Color: Purple
Green
Colors and the Complementary Colors of the Visible Spectrum
Wavelength: 506-555
Color Absorbed: Green
Complementary Color:
Purple
Colors and the Complementary Colors of the Visible Spectrum
Wavelength:
Color Absorbed: Green
Complementary Color: Purple
506 - 555
Colors and the Complementary Colors of the Visible Spectrum
Wavelength: 556-575
Color Absorbed:
Complementary Color: Violet
Yellow - green
Colors and the Complementary Colors of the Visible Spectrum
Wavelength: 556-575
Color Absorbed: Yellow-green
Complementary Color:
Violet
Colors and the Complementary Colors of the Visible Spectrum
Wavelength:
Color Absorbed: Yellow-green
Complementary Color: Violet
556 - 575
Colors and the Complementary Colors of the Visible Spectrum
Wavelength: 576-600
Color Absorbed:
Complementary Color: Blue
Yellow
Colors and the Complementary Colors of the Visible Spectrum
Wavelength: 576-600
Color Absorbed: Yellow
Complementary Color:
Blue
Colors and the Complementary Colors of the Visible Spectrum
Wavelength:
Color Absorbed: Yellow
Complementary Color: Blue
576 - 600
Colors and the Complementary Colors of the Visible Spectrum
Wavelength: 601-650
Color Absorbed:
Complementary Color: Green-blue
Orange
Colors and the Complementary Colors of the Visible Spectrum
Wavelength: 601-650
Color Absorbed: Orange
Complementary Color:
Green - blue
Colors and the Complementary Colors of the Visible Spectrum
Wavelength:
Color Absorbed: Orange
Complementary Color: Green-blue
601 - 650
Colors and the Complementary Colors of the Visible Spectrum
Wavelength: 651-700
Color Absorbed:
Complementary Color: Blue-green
Red
Colors and the Complementary Colors of the Visible Spectrum
Wavelength: 651-700
Color Absorbed: Red
Complementary Color:
Blue - green
Colors and the Complementary Colors of the Visible Spectrum
Wavelength:
Color Absorbed: Red
Complementary Color: Blue-green
651 - 700
____ provides polychromatic light and must generate sufficient energy or power to measure the analyte of interest.
Light source or Radiant source
To give accurate absorbance measurements throughout its absorbance range, the response to change of light source in light intensity must be ____.
linear
Types of Light or Radiant Source
- Continuum
- Line
____ emits radiation that changes in intensity.
Continuum source
Which type of light or radiant source is widely used in the laboratory?
Continuum source
Examples of Continuum Source
- Tungsten
- Deuterium
- Xenon
____ emits limited radiation and wavelength.
Line Source
Examples of Line Source
- Mercury and Sodium vapor lamps
- Hallow cathode tube
- Laser
____ minimizes unwated or stray light and prevents the entrance of scattered light into the monochromator system.
Entrance slit
Entrance slit minimizes ____ and prevents the entrance of ____.
unwatanted/stray light; scattered light
____ is any wavelength outside the band transmitted by the monochromator.
Stray light
____ limits the maximum absorbance that a spectrophotometer can achieve.
Stray light
____ is the most common cause of linearity at high analyte concentration.
Stray light
Stray light is the most common cause of ____ at high analyte concentration.
linearity
____ isolates specific or individual wavelength of light.
Monochromator
Kinds of Monochromator
- Prisms
- Diffraction gratings
- Filters
- Holographic gratings
____ are wedge-shaped pieces of glass, quartz, or sodium chloride.
Prisms
____ can be rotated, allowing only the desired wavelength to pass through an exit slit.
Prisms
A narrow light focused on a prism is ____ as it enters a more dense glass.
refracted
____ are most commonly used for it has a better resolution than prisms.
Diffraction gratings
____ are made by cutting grooves or slits into an illuminated surface of a flat piece of crown glass-wavelengths.
Diffraction gratings
Grooves of diffraction gratings
15,000 to 30,000 per inch
____ is simple and less expensive, but is not precise.
Filter
____ are made by placing semi-transparent silver films on both sides.
Filters
Filters are made by placing ____ on both sides.
semi-transparent silver films
____ produces monochromatic light based on the principle of constructive interference of waves.
Filter
Filters produce ____ based on the principle of constructive interference of waves.
monochromatic light
Filters produce monochromatic light based on the ____.
principle of constructive interference of waves
____ controls the width of the light beam.
Exit slit
Width is also called as ____.
bandpass
____ is the total range of wavelength transmitted.
Bandpass
____ allows only a narrow fraction of the spectrum to reach the cuvette.
Exit slit
The narrower the bandpass, the ____ the resolution.
greater
The ____ the bandpass, the greater the resolution.
narrower
The ____ holds the solution whose concentration is to be measured.
cuvette
Other names for cuvette
- Absorption cell
- Analytical cell
- Sample cell
Kinds of Cuvette
- Alumina silica glass
- Quartz/Plastic
- Borosilicate glass
- Soft glass
____ is the most commonly used cuvette.
Alumina silica glass
____ is used for the measurement of solution requiring visible and ultraviolet spectra.
Quart/Plastic Cuvette
____ transmit light effectively at a wavelength greater or equal to 220.
Silica Cuvette
The path length of a cuvette is ____.
1 cm
To increase sensitivity, some cuvettes are designed to have a path length of ____.
10 cm
____ detects and converts transmitted light into photoelectric energy.
Photodetector
Photodetector detects and converts transmitted light into ____.
photoelectric energy
Kinds of Photodetector
- Barrier Layer Cells/Photocell/Photovultaic Cell
- Phototube
- Photomultiplier tube
- Photodiode
____ is used in filter photometers with a wide bandpass.
Barrier Layer Cells/Photocell/Photovultaic Cell
____ is a basic photo transducer that is used for detecting and measuring radiation in the visible region.
Barrier Layer Cells/Photocell/Photovultaic Cell
____ is the simplest detector, least expensive, temperature sensitive, and non-linear.
Barrier Layer Cells/Photocell/Photovultaic Cell
____ has a photosensitive material that gives off electron when light energy strikes it.
Phototube
____ contain cathodes and anodes enclosed in a glass case.
Phototube
____ requires external voltage.
Phototube
Phototube requires ____.
external voltage
____ has an excellent sensitivity and has a rapid response.
Photomultiplier Tube
____ detects very low level of light.
Photomultiplier Tube
____ is the most commonly used detector for visible and UV region.
Photomultiplier Tube
____ can detect and amplify radiant energies.
Photomultiplier Tube
____ contains dynodes.
Photomultiplier Tube
____ are a series of anodes with high positive voltage.
Dynodes
____ is 200x more sensitive than phototube.
Photomultipler Tube
____ is not as sensitive as PMT but with excellent linearity.
Photodiode
____ measures light at a multitude of wavelength.
Photodiode
____ detects less amount of light.
Photodiode
____ is most useful as simultaneous multichannel detector.
Photodiode
____ displays output of the detection system.
Meter or read-out device
____ states that the concentration of the uknown substance is directly proportional to the absorbed light and inveresely related to the transmitted light.
Beer’s Law
According to Beer’s Law, the concentration of the unknown substance is ____ to the absorbed light.
directly proportional
According to Beer’s Law, the concentration of the unknown substance is ____ to the transmitted light.
inversely proportional
____ is the amount of light absorbed.
Absorbance
Absorbance cannot be measured directly by ____.
Spectrophotometer
____ states how much of the light the sample absorb.
Absorbance
Absorbance is also known as ____.
optical density
____ is the fraction of the incident light which is transmitted.
Transmittance
____ is the amount of light that successfully passes through the substance and comes out the other side.
Transmittance
____ contains serum but without the reagent to complete the assay.
Blank
____ corrects absorbance caused by the color of the reagent.
Reagent blank
Measures not effective in some cases of turbidity, ____ may be necessary.
ultracentrifugation
To correct for artefactual absorbance reading, ____ may be used.
blanking procedures or dual wavelength method
____ means that the wavelength indicated on the control dial is the actual wavelength of light passed by the monochromator.
Wavelength accuracy
____ is demonstrated when a change in concentration results in a straight line calibration curve.
Linearity
____ measures the light transmitted by a single atom burned in a flame.
Flame Emission Photometry (FEP)
Principle of Flame Emission Photometry (FEP)
Excitation of electrons from lower to higher state of energy
Principle: Excitation of electrons from lower to higher state of energy.
Flame Emission Photometry (FEP)
Flame Emission Photometry (FEP)
Light source
Flame
Flame Emission Photometry (FEP)
Method
Indirect Internal Standard Method
Flame Emission Photometry (FEP)
Internal standard
Lithium or Cesium
____ is used for the measurement of excited atoms such as Na and K.
Flame Emission Photometry (FEP)
Flame Emission Photometry (FEP)
____ indicates changes in the fuel reading of the instrument.
Flickering of light
____ measures the light absorbed by atoms dissociated by heat.
Atomic Absorption Spectrometry (AAS)
Principle of Atomic Absorption Spectrophotometry (AAS)
Element is not excited but merely dissociated from its chemical bond and placed in an unionized, unexcited, ground state.
Principle: Element is not excited but merely dissociated from its chemical bond and placed in an unionized, unexcited, ground state.
Atomic Absorption Spectrometry (AAS)
Atomic Absoprtion Spectrophotometry (AAS)
Light Source
Hollow Cathode Tube
Atomic Absoprtion Spectrophotometry (AAS)
Interferences
Chemical, matrix, and ionization
____ is used for measurement of unexcited trace metals such as Ca and Mg.
Atomic Absorption Spectrophotometry (AAS)
An ____ is used to convert ions to atom.
Atomizer
In AAS, a ____ is used to modulate the light source.
chopper
In AAS, ____ is added to samples to form stable complexes with phosphate.
Lanthanum or Strontium chloride
Volumetric Principle
The unknown sample is made to react with a known solution in the presence of an indicator.
Principle: The unkown sample is made to react with a known solution in the presence of an indicator.
Volumetric
Examples of Volumetric Method
- Schales and Schales Method
- EDTA Titration Method
____ is for measuring abundant large particles and bacterial suspension.
Turbidimetry
Principle of Turbidimetry
Determines the amount of light blocked by a particulate matter
Principle: Determines the amount of light blocked by a particulate matter.
Turbidimetry
Turbidimetry depends on ____.
specimen concentration and particle size
In turbidimetry, the solutions are measured using ____.
visible photometers or spectrophotometers
____ is used for protein measurements, bacterial growth, antibiotic sensitivity, and clot formation.
Turbidimetry
____ is more sensitive for protein measurement than turbidimetry.
Nephelometry
____ is for measuring the amount of antigen-antibody complexes.
Nephelometry
Nephelometry Principle
Determines the amount of scattered light by a particulate matter suspended in a turbid solution
Principle: Determines the amount of scattered light by a particulate matter suspended in a turbid solution.
Nephelometry
Light scattering depends on ____.
wavelength and particle size
Light scatered is measured at an angle typically, ___.
15 to 90 degrees
Components of Nephelometry
- Light source
- Collimator
- Monochromator
- Sample cuvette
- Stray light trap
- Photodetector
The ____ is proportional to concentration.
detector (PM tube) output
____ is the migration of charged particles in an electric field.
Electrophoresis
____ separates proteins on the basis of their electric charge densities.
Electophoresis
During electrophoresis, proteins are ___.
negatively charged
____ is the migration of small charged ions.
Iontophoresis
____ is the migration of charged molecules.
Zone electrophoresis
____ means that the net charge can either be positive or negative.
Amphoteric
____ is the movement of buffer ions and solvent that is relative to a fixed support.
Electroendosmosis or Endosmosis
Components of Electrophoresis
- Electric power
- Support medium
- Buffer
- Sample
- Detecting system
Supporting media for Electrophoresis
- Paper electrophoresis
- Starch Gel
- Cellulose Acetate
- Agarose Gel
- Polyacrylamide Gel
____ employs a filter paper strips soaked in a buffer solution, usually diethyl barbituric acid.
Paper electrophoresis
What is the usual buffer solution in paper electrophoresis?
Diethyl barbituric acid
____ separates by surface charge and molecular size.
Starch gel
____ separates by molecular size.
Cellulose acetate
____ is neutral; separates by electrical charge; does not bind to protein.
Agarose gel
____ neutral; separates on the basis of charge and molecular size.
Polyacrylamide gel
____ is a detector of electrophoretic machine.
Densitometer
____ measures the absorbance of the stain.
Densitometer
____ scan and quantify electrophoretic pattern.
Densitometer
____ reads gel and cellulose acetate membrane.
Densitometer
____ is directly proportional to net charge, and inversely proportional to molecular size and viscosity.
Electrophoretic mobility
Electrophoretic mobility is ____ to net charge, and ____ to molecular size and viscosity.
directly proportional; inversely proportional
At pH ____, the gamma globulins move toward the cathode, despite the fact that they are negatively charged.
8.6
After electrophoresis, the gel is treated with a mild fixative, such as ____, that precipitates the proteins at the positions to which they have migrated.
acetic acid
____ precipitates the proteins at the positions to which they have migrated.
Mild fixative (acetic acid)
Frequently, gel shows ____ in which samples at the center of the gel migrate further than those at the edges.
smile artifact
In ____, separating molecules migrate through pH gradient.
Isoelectric focusing
____ uses a constant gradient.
Isoelectric focusing
How is the pH gradient created in isoelectric focusing?
By adding acid to the anodic area of the electrolyte cell, and then adding base to the cathode area.
____ is ideal for separating proteins of identical sizes but with different net charges.
Isoelectric focusing
Supporting media for Isoelectric Focusing
- Agarose gel
- Polyacrylamide gel
- Cellulose acetate
Advantages:
* Ability to resolve mixtures of proteins
* Detect isoenzyme
* Identification of genetic variants
* Detect CSF oligoclonal band
Isoelectric focusing
In ____, samples molecules are separated by electro-osmotic flow.
Capillary electrophoresis
(+) charged ions move ____.
faster
(-) charged ions move ____.
slower
Uses:
* Separation, quantitation, and determination of MW of proteins
* Analysis of PCR
* Analysis of organic and inorganic substances and drugs
Capillary Electrophoresis