B - CHAPTER V: ANALYTICAL METHODS & INSTRUMENTATION Flashcards
– radiant energy; photons of energy travelling in a wavelike manner
ELECTROMAGNETIC ENERGY
- The shorter the [?], the higher the [?]
wavelength; electromagnetic energy
Types of Electromagnetic energies:
- Cosmic rays
- Gamma rays
- X-rays
- Visible
- Ultra-violet (UV)
- Infrared (IR)
- Radio, TV, microwave, etc.
- distance between two peaks as the light travels in a wavelike manner
WAVELENGTH
wavelength is expressed in
nanometers (nm), angstroms (Å), and millimicron (mµ)
- 1 nm = [?] = [?]
10 Å
1 mµ
Kinds of Wavelength:
- Visible spectra
- Non-visible spectra
= 340 nm – 700 nm
Visible spectra
(ultraviolet region)
= below 340 nm
(infrared region)
= above 700 nm
Kinds of Colorimetry:
- Visual Colorimetry
- Photoelectric Colorimetry
– relies on visual acuity to determine end-point
Visual Colorimetry
180 - 220
Short UV
220 - 340
Short UV
340 - 430
Visible
Violet
Yellow green
430 - 475
Visible
Blue
Yellow
475 - 495
Visible
Green blue
Orange
495 - 505
Visible
Blue green
Red
505 - 555
Visible
Green
Purple
555 - 575
Visible
Yellow green
Violet
575 - 600
Visible
Yellow
Blue
600 - 620
Visible
Orange
Green blue
620 - 700
Visible
Red
Blue green
– measurement of light intensity in a much narrower wavelength
SPECTROPHOTOMETRY
Makes use of prisms and/or diffraction gratings as monochromator to disperse the radiant energy into a continuous spectrum & isolate radiant energy of desired wavelength
SPECTROPHOTOMETRY
– measurements of light intensity of multiple wavelength
FILTER PHOTOMETRY
It makes use of filters (interference or transmission) to isolate part of the spectrum
FILTER PHOTOMETRY
Light passes through a [?] to provide a selection of the desired region of the spectrum to be used for measurements.
monochromator
are used to isolate a narrow beam of light and to improve its chromatic purity.
Slits
The light next passes through an [?] where a portion of the [?] is absorbed, depending upon the of the solution.
absorption cell
radiant energy
nature and concentration
Any light not absorbed is transmitted to a [?], which converts the light energy to [?] that can be registered on a [?] or a [?].
detector
electrical energy
meter/digital read-out
BEER’S LAW: The [?] is directly proportional to the [?] and inversely proportional to the [?]
concentration of the solution
amount of light absorbed
logarithm of transmitted light
%T = [?]
Absorbance / Optical Density (O.D.) =
ratio of the radiant energy transmitted, divided by the radiant energy incident on the sample
the amount of light absorbed
BOUGUER’S LAW or LAMBERT’S LAW: [?] is directly proportional to the [?] of light path
Absorbance
length
? = absorbance
A
? = proportionality constant or molar absorptivity or extinction coefficient. Constant for a given compound at a given wavelength under prescribed condition of solvent, temperature, pH, etc.
a
[?] = length of light path in cm
b
[?] = molar concentration of absorbing substance
c
Internal Parts of the Spectrophotometer
source
entrance slit
despersion device
exit slit
sample
detector
A – Light Source
E – Cuvet
B – Entrance slit
F – Detector
C – Monochromator
G – Meter
– provides a continuous spectrum of white light which can be separated at different wavelengths
LIGHT SOURCE
– isolates a narrow beam of radiant energy; prevents stray light from entering the monochromator
ENTRANCE SLIT
– wavelength selector; isolates radiant energy of desired wavelength and excluding that of other wavelengths
MONOCHROMATOR
– used to hold the solution whose concentration is to be measures
ANALYTICAL / ABSORPTION CELL / CUVETTE
– measure light intensity by converting light signal into electrical signal
DETECTORS
– electrical energy from a detector is displayed
READ-OUT DEVICES
TYPES OF LIGHT SOURCE
A. Tungsten Iodide lamp
B. Quartz Halide lamp
C. Deuterium Discharge lamp
D. Infrared Energy source
E. Mercury Vapor lamp
F. Hollow Cathode lamp
TYPES OF MONOCHROMATOR
A. Prism
B. Diffraction Gratings
C. Transmission Filters
D. Interference Filters
TYPES OF ANALYTICAL / ABSORPTION CELL / CUVETTE
a. Borosilicate glass
b. Quartz or plastic
c. Alumina silica glass
TYPES OF DETECTORS
a. Barrier-Layer cell (Photocell or Photovoltaic cell)
b. Photoemissive tube or Phototube
c. Photoconductive tube or Photoresistive tube
d. Photomultiplier tube
– produces energy wavelength from 340 – 700 nm (visible region); used for moderately diluted solution
A. Tungsten Iodide lamp
– contains small amounts of halogen such as iodine to prevent the decomposition of the vaporized tungsten from the very hot filament
B. Quartz Halide lamp
– provides energy source with high output in the UV range (down to 165 nm)
C. Deuterium Discharge lamp
– used above 800 nm
D. Infrared Energy source
– emits narrow bands of energy at well-defined places in the spectrum (UV and visible)
E. Mercury Vapor lamp
– consists of a gas-tight chamber containing anode, a cylindrical cathode, and inert gas such as helium or argon
F. Hollow Cathode lamp
Infrared Energy source Examples:
Merst glower
Globar
– an electrically heated rod of rare earth element oxides
Merst glower
– uses silicon carbide
Globar
– wedge-shaped pieces of glass, quartz, NaCl, or some other material that allows transmission of light
Prism
o Disperses white light into a continuous spectrum of colors by refraction
Prism
o Produces a non-linear spectrum.
Prism
are for visible region while quartz prisms are for the UV region
o Glass prisms
The (?) are close to each other and those of (?) are widely spaced.
longer wavelengths
shorter wavelengths
– consist of a thin layer of aluminum-copper alloy on the surface of a flat glass plate that has many small parallel grooves ruled into the metal coating
Diffraction Gratings
o Rays of radiant energy bend (refract) around the sharp edges of the grooves
Diffraction Gratings
o Extent of refraction varies with the wavelength
Diffraction Gratings
– colored glass or colored gelatin sandwiched between two glass plates
Transmission Filters
o Light outside the transmission band are absorbed by the colored material
Transmission Filters
o Band pass is 35 – 50 nm or more
Transmission Filters
– dielectric material (e.g. NaF) sandwiched between two half-silvered pieces of glass
Interference Filters
o The thickness of the layer determines the wavelength of energy transmitted.
Interference Filters
o Band pass is 10 – 20 nm
Interference Filters
– for solutions that do not etch glass
a. Borosilicate glass
– does not absorb UV radiation at wavelength below 320 nm
b. Quartz or plastic
– good for 340 nm and above (visible region)
c. Alumina silica glass
- Composed of a film of light sensitive material (e.g. Selenium) on an iron plate with a transparent layer of silver
a. Barrier-Layer cell (Photocell or Photovoltaic cell)
- When light passing through the semi-conductive metal layer falls upon the Selenium surface, electrons are released in proportion to the intensity of light and are collected to the silver layer to produce a negative charge
a. Barrier-Layer cell (Photocell or Photovoltaic cell)
- Has photosensitive material that gives off electrons when light energy strikes it
Photoemissive tube or Phototube
- Consists of 2 electrodes (cathode and anode) sealed in an evacuated glass
Photomultiplier tube
- A device whose electrical resistance decreases as the level of incident light is raised
Photoconductive tube or Photoresistive tube
- Cadmium sulfide or cadmium selenide are the light-sensitive materials typically used for the visible region
Photoconductive tube or Photoresistive tube
- Does not require an external power source
Photoconductive tube or Photoresistive tube
- Capable of significantly amplifying a current
Photomultiplier tube
- The cathode is a negative light-sensitive metal that absorbs light and emits electrons in proportion to the radiant energy that strikes the surface
Photomultiplier tube
- Electrons go to the dynodes, where electrons produce 4 – 6 additional electrons
Photomultiplier tube
- The electrons are collected at a final electrode, the positive anode
Photomultiplier tube
Photomultiplier tube Advantages:
- rapid response time
- very sensitive
- low fatigue
– electrical energy from a detector is displayed
READ-OUT DEVICES
– the output of the detector is used to drive a sensitive meter directly without further amplification
a. Direct reading system
– the output of the detector is balanced against the output of a reference circuit
b. Null Point System
– numerical display of absorbance or converted values of concentrations
c. Digital Read-out
K
DOUBLE BEAM SPECTROPHOTOMETERS
- Double Beam-In-Space
- Double Beam-In-Time
• All components are duplicated except the light source
Double Beam-In-Space
• The beams of light pass through different components but at the same time
Double Beam-In-Space
• Uses a light beam chopper (a rotating wheel) – with alternate silvered sections and cut out sections, inserted after the exit slit
Double Beam-In-Time
It involves the measurement of emitted light when electrons in an atom become excited by heat energy produced by the flame.
FLAME PHOTOMETRY / FLAME EMISSION SPECTROPHOTOMETRY / FILTER PHOTOMETRY
When these electrons return to their ground state, they emit light characteristic of the ions present.
FLAME PHOTOMETRY / FLAME EMISSION SPECTROPHOTOMETRY / FILTER PHOTOMETRY
It is used primarily to determine concentration of sodium, potassium or lithium since these alkali metals are easy to excite
FLAME PHOTOMETRY / FLAME EMISSION SPECTROPHOTOMETRY / FILTER PHOTOMETRY
Sodium =
yellow
Rubidium =
red
Potassium =
violet
Magnesium =
blue
Lithium =
red
COMPONENTS of the FLAME PHOTOMETER
- GASES
- BURNER ASSEMBLY
- INTERFERENCE FILTERS as MONOCHROMATOR
- DETECTOR
Types of Burner:
A. Total Consumption Burner
B. Premix Burner
mixture of hydrogen and oxygen gas
- acetylene
- propane
- natural gas
BURNER ASSEMBLY
a. Aspirator
b. Atomizer (Nebulizer )
c. Flame
– draws sample into the flame
a. Aspirator
– creates a fine spray of sample solution to be fed into the flame of the burner
b. Atomizer (Nebulizer )
– provides heat energy for excitation
c. Flame
– aspirate sample directly into the flame, the gases are passed at high velocity over the end of the capillary suspended in the solution
A. Total Consumption Burner
– involves the gravitational feeding of solution through a restricting capillary into an area of high velocity gas flow where small droplets are produced and passed into the flame
B. Premix Burner
- transmit yellow light (589 nm)
Na filter
- transmit violet light (767 nm)
K filter
- transmit red light (761 nm)
Lithium
DETECTOR – uses photocell as detector
FLAME PHOTOMETRY
The Internal Standard in Flame Photometry: Uses (?)
Lithium or Cesium
In AAS, the element is not excited in the flame but merely dissociated from its (?) and placed in an unexcited state. The atom, at a (?), absorbs light. The (?) emits radiant energy to be absorbed by the .
chemical bond
lower energy level
light source; element
- Measures the amount of light absorbed by ground state atom
ATOMIC ABSORPTION SPECTROPHOTOMETRY (AAS)
COMPONENTS OF ATOMIC ABSORPTION SPECTROPHOTOMETRY (AAS)
- LIGHT SOURCE
- MECHANICAL ROTATING CHOPPER
- BURNER
- MONOCHROMATOR
- DETECTOR
- METER or READ-OUT DEVICE
– hollow cathode lamp, which produces a wavelength of light specific for the kind of metal in the cathode
- LIGHT SOURCE
– modulates light beam coming from the hollow cathode lamp
- MECHANICAL ROTATING CHOPPER
– uses flame to dissociate the chemical bonds and form free, unexcited atoms
- BURNER
Two types of Burner:
a. Total Consumption burner
b. Pre-mix burner
– flame is more concentrated and can be made hotter, thus lessening chemical interferences.
a. Total Consumption burner
– gases are mixed and the sample is atomized before entering the flame and the large droplets go to waste and not in the flame.
b. Pre-mix burner
It has less noisy signals with longer pathlength and greater absorption and sensitivity.
b. Pre-mix burner
– selects the desired wavelength from a spectrum of wavelength which could either be a prism or a diffraction grating.
- MONOCHROMATOR
– uses photomultiplier tubes to measure the intensity of the light signal.
DETECTOR
– energy emission that occurs when certain compounds absorb electromagnetic radiation, become excited and then return to an energy level that is usually slightly higher than their original level.
FLUORESCENCE
COMPONENTS OF FLUORESCENCE SPECTROPHOTOMETRY
- LIGHT SOURCE
- MONOCHROMATORS:
a. Primary filter / Excitation filter
b. Secondary filter / Emission filter - PHOTOMULTIPLIER
- READ-OUT DEVICE
– hydrogen discharge lamp or xenon lamp
- LIGHT SOURCE
- MONOCHROMATORS:
a. Primary filter / Excitation filter
b. Secondary filter / Emission filter
– isolates the ultraviolet light
a. Primary filter / Excitation filter
– isolates secondary emission (filter, prism or diffraction grating)
b. Secondary filter / Emission filter
– separation of a substance in a pure form and then determining its dry weight
GRAVIMETRIC METHOD
GRAVIMETRIC METHOD Example:
Total Lipid determination
– the unknown sample is made to react with a known solution (titrating agent) in the presence of an indicator
VOLUMETRIC / TITRIMETRIC METHOD
VOLUMETRIC / TITRIMETRIC METHOD Example:
Chloride determination (Schales & Schales)
– measurement of the amount of light blocked by a particulate matter suspended in solution (180° to the incident beam)
TURBIDIMETRY
Factors affecting turbidimetry:
o Size and number of particles
o The depth of the tube
o Cross-sectional area of each particle
– detection of light energy scattered or reflected toward a detector that is not in the direct path of the transmitted light (90° to the incident beam)
NEPHELOMETRY
– detection of light energy scattered or reflected toward a detector that is not in the direct path of the transmitted light (90° to the incident beam)
NEPHELOMETRY
• The factors affecting turbidimetric measurements are the same factors affecting (?) measurements
nephelometric
• It is more specific than turbidimetry
NEPHELOMETRY
– it is used to measure the disintegration of a radioisotope per minute
SCINTILLATION COUNTER
Types of Radiation:
- Alpha
- Beta
- Gamma
– positively charged particles; resemble the nucleus of helium atom with a mass of 4 o Have very little energy
- alpha
– resembles an electron with both negative (β-) and positive (β+) charges but essentially no mass o Exists in two forms: soft and hard beta
- Beta
– a form of electromagnetic energy with no mass, only energy o Exists in two forms: soft and hard gamma
- Gamma
Types of Scintillation Counters:
- Solid Scintillation Counter
- Liquid Scintillation Counter
– measures gamma radiation using thallium activated NaI crystal as scintillator and PM tube as detector with preamplifier circuit
- Solid Scintillation Counter
– measures beta radiation using liquid flour as scintillator
- Liquid Scintillation Counter
– an immunologic procedure involving the use of radioisotope
RADIOIMMUNOASSAY
Substances involved in RIA:
- Unlabelled antigen (Ag)
- Radiolabelled antigen (Ag)
- Antibody
– substance being analyzed
- Unlabelled antigen (Ag)
– acts as label 3.
- Radiolabelled antigen (Ag)
– provide binding site for the two antigens
- Antibody
Types of RIA:
- Solid RIA
- Liquid RIA
– measurement of differences in voltage at a constant current
POTENTIOMETRY
o The unknown voltage introduced into the potentiometer circuit opposes a known reference voltage
POTENTIOMETRY
o The voltage of the unknown is measured by comparison to determine the voltage required to exactly oppose the flow of current in the test circuit
POTENTIOMETRY
o The relationship between the measured voltage and the sought-for concentration
POTENTIOMETRY
The relationship between the measured voltage and the sought-for concentration is shown by the Nernst Equation
POTENTIOMETRY
– measurement of differences in current at a constant voltage
POLAROGRAPHY
o Used to measure trace metals, oxygen, Vit. C, and amino acid concentration
POLAROGRAPHY
o The relationship between the differences in current and voltage is shown by the Ilkovic Equation
POLAROGRAPHY
– the measurement of the amount of electricity (in coulombs) at a fixed potential
COULOMETRY
is equal to a current flow of 1 ampere per second
coulomb
o The (?) consumed can be related directly to the concentration of the unknown
number of coulombs
o The relationship is expressed by the Faraday’s Law
COULOMETRY
– measurement of the amount of current that flows when a constant voltage is applied to the measuring electrode
AMPEROMETRY
– measurement of the current flow between two non-polarizable electrodes between which a known electrical potential is established
CONDUCTOMETRY
• Separation is based on solubility
PRECIPITATION
The precipitate is studied by:
a. Turbidimetric method
b. Chemical reaction (after being dissolved)
c. Gravimetric method
- separates dissolved materials
ULTRAFILTRATION
- removes particulate matter
ULTRAFILTRATION
- separation of dissolved molecules
DIALYSIS
- movement through a semi-permeable membrane driven by a force or pulled through a vacuum
ULTRAFILTRATION
- movement through a semi-permeable membrane more freely
DIALYSIS
Cellulose esters
Cellulose acetate Polyamide
Polyvinyl chloride
Sheets, disks or hair thin fibers, conical
ULTRAFILTRATION
Cellophane (regenerated cellulose) in sheets or tubing
DIALYSIS
- For desalting, fractionation of protein solutions and the preparation of pff
ULTRAFILTRATION
- Employed in continuous flow automated systems
DIALYSIS
- used to purify or concentrate samples
DIALYSIS
CHROMATOGRAPHY Requires two (2) phases:
(1) Solid support
(2) Mobile phase
– coated or uncoated
(1) Solid support
– flowing gas or liquid
(2) Mobile phase
TWO GENERAL TYPES of CHROMATOGRAPHY:
A. Adsorption Chromatography
B. Partition Chromatography
– molecules separated are adsorbed at the surface of a solid support or flow with the mobile phase
A. Adsorption Chromatography
– solid support is coated with a film of water or non-volatile organic liquid
B. Partition Chromatography
Partition Chromatography Examples:
TLC, GLC
- Paper Chromatography
a. Solid or immobile phase
b. Mobile phase
– paper is composed of cellulose; the matrix of cellulose is bound to water
a. Solid or immobile phase
– organic solvent
b. Mobile phase
o involves partition between water and organic solvent
Mobile phase
o if the molecules are more soluble in the flowing solvent, the faster it will move along the paper
Mobile phase
o if the molecules are more soluble in water, they do not move very fast
Mobile phase
Rf = ratio of the distance of movement by a (?) to the distance of the (?) front
compound
solvent
Rf = a/B
Where:
a = distance travelled by (?) from origin to front of spot
b = distance travelled by (?)
compound
solvent
o Uses a flat sheet of chromatographic material
Thin Layer Chromatography
Thin Layer Chromatography Advantages over paper chromatography
• Solid Support
• Mobile Phase
Thin Layer Chromatography
• Solid Support: water bound to
a. Silica or silicic acid
b. Alumina – aluminum oxide + aluminum hydroxide
Thin Layer Chromatography
• Mobile Phase:
organic solvent
Thin Layer Chromatography
Qualitative analysis:
based on colors and positions
Thin Layer Chromatography
Quantitative analysis:
remove spots and extract
o Separation is based on electrical charge
Ion-Exchange Chromatography
– capture anions
o Anion exchangers
– capture cations
o Cation exchangers
Ion-Exchange Chromatography
• Stationary / Immobile / Solid support
a. Aluminum silicate
b. Polysaccharide
c. Synthetic resins – polystyrene beads
Ion-Exchange Chromatography
• Mobile Phase:
water
o Separation is based on differences in molecular size
Gel Filtration / Molecular Sieve / Gel Permeation / Size Exclusion / Molecular Exclusion
Gel Filtration / Molecular Sieve / Gel Permeation / Size Exclusion / Molecular Exclusion
• Stationary phase
a. Polyacrylamide (plastic)
b. Sephadex (cross-linked polysaccharide)
c. Porous beads
Gel Filtration / Molecular Sieve / Gel Permeation / Size Exclusion / Molecular Exclusion
• Mobile phase:
flowing water
Gas Chromatography
Two general types:
a. Gas – Liquid Chromatography (GLC)
b. Gas – Solid Chromatography (GSL)
Gas Chromatography
• Stationary Phase –
diatomaceous earth (silica) coated with a non-volatile organic liquid = silicone polymer or alcoholic wax
Gas Chromatography
– inert carrier gas (Helium or Nitrogen)
• Mobile Phase
a. Gas – Liquid Chromatography (GLC) –
b. Gas – Solid Chromatography (GSL) –
based on partition
based on adsorption
❖ Involves the migration of charged solutes or particles in a supporting medium under the influence of an electric field
ELECTROPHORESIS
– migration of small ions or molecules
• Iontophoresis
– migration of charged macromolecules in a porous medium such as cellulose acetate, paper or agarose
• Zone electrophoresis
➢ it generates an ELECTROPHORETOGRAM – a display of protein zones
• Zone electrophoresis
– a display of protein zones
ELECTROPHORETOGRAM
ELECTROPHORESIS
Principle:
• An ampholyte carries either a positive (+) or negative (-) charge; a (?)
• In an acid solution, an ampholyte receives protons and thereby carries a net (+) charge and migrates towards the (?)
• In an alkaline solution, an ampholyte gives up protons and thereby carries a net (-) charge and migrates towards the (?)
zwitterion
CATHODE
ANODE
Migration depends on:
- Net electrical charge of molecule
- Size and shape of the molecule
- Strength of the electrical field
- Properties of the support medium
- Temperature of operation
STAINS:
Protein Stains
Isoenzymes: Nitrotetrazoleum Blue
Lipoprotein
Protein Stains
o Amido Black
o Bromphenol Blue
o Coomasie Brilliant Blue
o Nigrosin
o Ponceau S
Lipoprotein
o Fat Red 7B (Sudan Red)
o Oil Red O
o Sudan Black B
TYPES of ELECTROPHORESIS:
- Paper Electrophoresis (PE)
- Agarose Gel Electrophoresis (AGE)
- Cellulose Acetate Electrophoresis (CAE)
- Polyacrylamide Gel Electrophoresis (PAGE)
- Starch Gel Electrophoresis 6. Isoelectric Focusing
ISOELECTRIC FOCUSING An electrophoretic method in w/c proteins are separated on the basis of their pI (isoelectric pH)
An electrophoretic method in w/c proteins are separated on the basis of their pI (isoelectric pH)
ISOELECTRIC FOCUSING
Makes use of the property of proteins that their net charges are determined by the pH of their local environment
ISOELECTRIC FOCUSING
Proteins show considerable variation in pI, but pI values fall in the range pH 3–12 (many having pIs between pH 4–7)
ISOELECTRIC FOCUSING
- Establishing pH gradients
Accomplished w/ the use of:
a. Carrier Ampholytes (Amphoteric electrolytes)
b. Acrylamide buffers
2. Gel for Isoelectric Focusing
- Mixtures of molecules containing multiple aliphatic amino & carboxylate groups (buffer molecules)
Carrier Ampholytes (Amphoteric electrolytes)
- Included directly in IEF gels
Carrier Ampholytes (Amphoteric electrolytes)
- Derivatives of Acrylamide containing both reactive double bonds & buffering groups
Acrylamide buffers
- Covalently incorporated in PAG at the time of casting
Acrylamide buffers
Gel for Isoelectric Focusing
❖ Polyacrylamide Gel
– large-pore convective matrices - Polymerized with an initiator system including Riboflavin for photo-polymerization
❖ Polyacrylamide Gel
– introduction of the 1st automated analyzer by Technicon
- Continuous-flow
1957
: sequential batch analyzer capable of providing single test result on approx. 40 samples / hour
- Continuous-flow
– Technicon instruments w/c were next developed
Simultaneous Multiple Analyzer (SMA)
- With multiple channels (for diff. tests)
Simultaneous Multiple Analyzer (SMA)
- 6-12 test results simultaneously at the rate of 360
Simultaneous Multiple Analyzer (SMA)
– 720 tests per hour
Simultaneous Multiple Analyzer (SMA)
– specialty area w/ rapidly developing arsenal of analyzers
IMMUNOCHEMISTRY
- Immunological techniques for assaying drugs, specific proteins, tumor markers & hormones
IMMUNOCHEMISTRY
- Fluorescence Polarization Immunoassay
- Nephelometry
- Chemiluminescent Detection
IMMUNOCHEMISTRY
BASIC APPROACHES OF AUTOMATED ANALYZERS
I. CONTINUOUS - FLOW
II. CENTRIFUGAL ANALYSIS
III. DISCRETE ANALYSIS
- Liquids (reagents, diluents & samples) are pumped through a system of continuous tubing
CONTINUOUS - FLOW
- Samples are introduced in a sequential manner, following each other through the same network
CONTINUOUS - FLOW
- Batch analysis can be used (e.g. large # of specimen in one run)
CONTINUOUS - FLOW
More sophisticated continuous flow anayzers Use parallel single channels to run multiple tests on each sample (e.g. SMA & SMAC)
CONTINUOUS - FLOW
Major drawbacks: significant carry-over problems & wasteful use of continuously flowing reagents
CONTINUOUS - FLOW
- Uses the force generated by centrifugation to transfer & then contain liquids in separate cuvets for measurement
CENTRIFUGAL ANALYSIS
- Capable of running multiple samples, one test at a time, in a batch MAJOR ADV.: batch analysis (e.g. COBAS - Bio by Roche Diagnostics)
CENTRIFUGAL ANALYSIS
– Bio by Roche Diagnostics)
CENTRIFUGAL ANALYSIS
- Most popular & versatile
DISCRETE ANALYSIS
- Separation of each sample & accompanying reagents in a separate container
DISCRETE ANALYSIS
- Capability of running multiple tests one sample at a time OR multiple samples one test at a time
DISCRETE ANALYSIS
- Random access, stat capabilities
DISCRETE ANALYSIS
Use parallel single channels to run multiple
tests on each sample (e.g. SMA & SMAC)
CONTINUOUS - FLOW
