analytic techniques sc

7/28/2019 Analytic Techniques Sc

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SPECTROMETRY SPECTOPHOTOMETRY ATOMIC ABSORPTION MASS SPECTROMETRY

LUMINESCENCE FLUORESCENCE CHEMILUMINESCENCE NEPHELOMETRY

ELECTROANALYTIC METHODS ELECTROPHORESIS

POTENTIOMETRY AMPEROMETRY

CHROMATOGRAPHY GAS LIQUID THIN-LAYER


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PHOTOMETRY measure light intensity without consideration of

wavelength

SPECTROPHOTOMETRY Measurement of light intensity in a selected wavelength

ELECTROMAGNETIC RADIATION (EMR) Photons of energy traveling in waves

Includes spectrum of energy from short-wavelength,highly energetic gamma rays and x-rays


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AMPLITUDE Length of electronic vector at maximum peak height.

PERIOD (p) Time in seconds required for the passage of successive maxima or

minima though a fixed point in space. FREQUENCY (v)

Number of oscillation of waveform in second Expressed in Hertz (Hz)

Corresponds to the cycle per seconds

WAVELENGTH Linear distance between any two equivalent points on a successivewave.

UNIT: nanometer (nm) millimicron

angstrom


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STRAY LIGHT

Any wavelength outside the band transmitted by

the monochromator. Common cause: reflection of light from scratches

on optical surfaces or from dust particles and high

order spectra produce by diffraction gratings

Polychromatic light

All visible wavelengths are present


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Ultraviolet 180-340 nm

Visible 350 700 nmInfrared 700 - 900 nm


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Wavelength Color absorbed Complementary color

350 430 Violet Yellow-blue

430-475 Blue yellow

475-495 Green-blue orange

495-505 Blue green red

505-555 Green Purple

555-575 Yellow green Violet

575-600 Yellow Blue600-650 Orange Green-blue

650-700 Red Blue-green


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Where h = erg sec(plancks constant)

v= frequencyE= energy

Energy is directly proportional to FrequencyFrequency is inversely proportional to wavelength

Energy is inversely proportional to wavelength


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Concentration of a substance is directly proportionalto the amount of light absorbed or inverselyproportional to the logarithm of transmitted light

A = absorbance

a = absorptivity of a compoundb=light path of the solution

c = concentration of compound

%T= percent transmittance


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Light Source Entrance slit Reduce stray light and prevents scattered light

from entering the monochromator Monochromator Exit slit

Prevent stray light from entering the cuvet. Analytic cell or Cuvet Photodetector Readout device


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Provides polychromatic light and must generatesufficient radiant power to measure the analyte of

interest.

TYPES

Continuum source

Emits radiation that changes in intensity very slow as a functionof wavelength

EX: tungsten, deuterium, xenon

Line source

Emit a limited number of discrete lines or bands of radiation, eachof which spans a limited range of wavelengths.


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Deuterium-discharge lamp and mercury arc Most commonly used for ultraviolet (UV) work

DEUTERIUM provides continuous emission down to 165 nm

MERCURY LAMP- Low Pressure Mercury Lamps emit sharp line spectrum, with both UV

and visible line.

Medium and High-pressure mercury lamps emit a continuum fromUV to the mid visible region

Incandescent tungsten or tungsten-halogen lamp Most common source of light in the visible and near-infrared

region.

Silicone carbide - IR Merst glower - IR


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Range Spectral distribution within the range

The source of radiant production Stability of the radiant energy Temperature


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A system of isolating a desired wavelengthand excluding others

BANDPASS Total range of wavelength submitted

With at more than half the maximum transmittance.


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Diffraction Gratings Most commonly used Consist of 15000 or 30000 per inch etched onto a polished surface parallel

grooves DIFFRACTION- the separation of light into component wavelength

Prism Short wavelengths are refracted more than long wavelengths, resulting in

dispersion of white light into continuous spectrum. Wedge-shaped pieces of glass , quartz or sodium chloride.

Interference Filter Principle: constructive interference of waves.

Magnesium fluoride with micro-mirror Pass very narrow range of wavelength with good efficiency

Colored-glass filters Pass a relative wide band of radiant energy and have a low transmittance of

the selected wavelength


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Quality of monochromators are described by

Nominal wavelength

Represents the wavelength nanometer at peaktransmittance

Spectral bandwidth

Range of wavelengths above one half peak

transmittance Bandpass

Total range of wavelength transmitted


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Square cuvets have an advantage over roundcuvets in that there is less error from the lens

effect,orientation in the spectrophotometerand refraction. Silicate glasses- 350-2000nm GLASS CUVETS- visible range QUARTZ CUVETS -UV radiation. Polycarbonate plastic both visible and UV

region


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Converts the transmitted radiant energy into an equivalentamount of electrical energy

BARRIER-LAYER CELLS/ PHOTOCELLS/PHOTOVOLTAIC Least expensive

Composed of a film of light sensitive material ~SELENIUM, on a plateof iron Do not require external voltage source, rely on internal electron

transfer to produce a current in an external circuit Output of electrical energy is not easily amplified Used mainly for in filter photometers with wide band pass,

producing a fairly high level of illumination so that there is no need toamplify the signal Inexpensive, durable Temperature sensitive and nonlinear at very low and very high levels

of illumination


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PHOTOTUBE

Also has photosensitive materials that gives off

electrons when light energy strikes it Requires an outside voltage

Has negatively charge cathode and positively

charge anode enclosed in gas case.

CATHODE: (rubidium, lithium) resistor on dark butemits electrons when exposed to light

A vacuum within tubes avoids scattering of thephotoelectrons by collision with gas molecules.


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PHOTOMULTIPLIER TUBE(PMT)

detects and amplifies radiant energy

DYNODES- series of anodes that gives off manysecondary electrons when hit by single electron.

200x more sensitive than phototube.

Extremely sensitive to very low light levels and

light flashes of very short duration.

Analog signalvoltagedigital signal (A/D

converter)absorbance reading


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SILICON DIODE TRANSDUCERS

More sensitive than phototubes but less sensitive

than PMT Spectral ranges from 190-1100 nm.

Positively (p) and negatively (n) charge semi

conductive materials adjoining one another

embedded on a silicon chip


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MULTICHANNEL PHOTON TRANSDUCER

Consist of array of small photoelectric sensitive

elements arranged either linearity or in a twodimensional pattern on a semiconductor chip.

CHIP- usu. SILICON Contains electronic circuitry making it possible to determine

the electric output signal sequentially or simultaneously.


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PHOTODIODE ARRAY (PDA) Produce one dimension array of several hundred photodiodes

set side-by-side on a single integrated circuit (IC) CHARGE-TRANSFER DEVICE

Two dimensional array detectors that operate on a chargetransfer process

CTD- released electron from the bound state to mobile state.

Charge-injection devicesCharge accumulated in each pixel can be measured independently and

nondestructively by using a network of sensing electrodes Charge couple devices

Charged packet are moved in-step along the array row from one pixelto the next as in a bucket chain


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WAVELENGHT ACCURACY

Wavelength indicated on the control dial is the

actual wavelength of light passed by themonochromator

DYDIMIUM or HOLMIUM OXIDE IN GLASS

Frequently used filter to check wavelength accuracy.

MERCURY VAPOR LAMP Verify wavelength accuracy in narrow band pass.

LINEARITY


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Display the magnitude of the electric currentfrom a detector METER READING DEVICE

Displays the analog detector signal by reflecting the needlealong the a scale

DIGITAL READOUT DEVICE Send the detector signal through an analog to digital

converter (A/D) and the microprocessor to display resultsusing a light-emitting diode (LED) or liquid crystal display(LCD)

RECORDER (STRIP CHART OR INTEGRATOR) Maybe connected extremely to give tracing of the detector

output against time or wavelength.


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Splits monochromatic light in 2 components One beam passes through sample and other

through a reference solution or blank Additional beam corrects for variation in light

source intensity The absorbance of the sample can be

recorded as the electrical output of thesample beam


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1. DOUBLE-BEAM IN TIME

Uses one photodetector and alternately passes

the monochromatic light though the samplecuvet and then reference cuvet using a chopper.

2. DOUBLE-BEAM IN SPACE

Uses 2 photodetector, for the sample beam and

reference beam


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Used to measure concentration by deletingabsorption of electromagnetic radiation by

atoms rather than by molecules The element is not excited but merely

dissociated from its chemical bonds and

placed in a unexcited, ground state.`


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If an element can be excited by externalenergy to emit radiation of a specific

wavelength, the element in the ground statewill absorb radiation of exact wavelength.


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PARTS

1. Light Source

2. Atomizer or burner3. Monochromator

4. Photomultiplier tube

5. Meter or Recorder


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1. Light source:

Hallow-cathode lamp

Consist of an evacuated gas-tight chamber containing ananode, a cylindrical cathode and an inert gas such asHELIUM and ARGON

Electrodeless discharge lamp

Bulb is filled with ARGON and the element to be tested


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Flame serves as a sample cell.2. ATOMIZER or BURNER Produces the flame Two light signals from the flame

1. Alternating signal from hollow cathode lamp2. Direct signal from the flame emission

PREMIX LONG-PATH BURNER Most common burner Sample are aspirated, mixed with air and fuel, large droplets go to

waste.

TOTAL CONSUMPTION BURNER Gasses like hydrogen and air and the sample are not mixed before

entering the flame


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3. MONOCHROMATOR Serves to protect the photodetector from excessive light

emanating from flame emission USES GRATING BECAUSE

Dispersion of spectrum is linear Has higher efficiency at UV region Its spectrum is not distorted by temperature changes.

4. PHOTOMULTIPLIER TUBE Light detector Uses very stable AC-type electronic amplifier to boost

the inherent amplification5. METER OR RECORDER Reads at mEq/L


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Advantage Sensitive and precise For trace metal

Propane or air acetylene flame remain in the groundstate available for light absorption~ accurate, preciseand specific

Disadvantage Inability of the flame to dissociate samples into free

atoms. Ionization of atoms following dissociation by the

flame Matrix interference


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INDUCTIVE COUPLES PLASMA Increase sensitivity for atomic emission.

An argon plasma maintained by the interaction ofradiofrequency field and an ionized argon gas, isreported to have used temperatures between5500K and 8000K

Recommended for determination of zirconium,uranium and boron

ICP with MC is the most sensitive and specificassay technique for all elements in periodic chart.


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Requires electrothermal atomization

Electric furnace to break chemical bonds

Electric current passes through the cylinder walls,evaporated the solvent, ashes the sample andheats the unit to incandescence to atomize the

sample.

Determine amount if light absorbed


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Measures the light emitted by a single atom burned ina flame

Principle: Excitation of electrons from lower to highenergy state

Light source: flame (also serves as cuvette) Method: Indirect internal standard method Internal standard:Lithium/cesium to correct for the variation in flame and atomizer

characteristic Used for the measurement of excited ions (sodium

and potassium) Flickering light indicates changes in fuel reading in

instrument


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Must not normally be present in a biologicfluid

Excitation energies of IS and that of elementbeing analyzed must be close Emission lines of IS and the element analyzed

must be well separated.


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Sodium yellow Potassium Violet

Lithium Red Rubidium Red

Magnesium - Blue


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1. Atomizer or burnerBreaks up the specimen aliquot into fine droplets

2. FlameCauses the evaporation of the solvent from the sample to producedry salt

Hard flame Blue

Soft flame Red Orange

3. Gas and Air supplyPropane gas

4. MonochromatorAllows only emitted line spectrum of an element under study tostrike the PM tube while rejecting the flame spectrum

5. PM tube6. Readout device

Galvanometer or recorder


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Measurement of fluorescence Determine the amount of light emitted by a

molecule after excitation by electromagneticradiation. Fluorescence occurs when electrons give off

light as they drop from the excited state back

to their ground state within a molecule Highly specific because of SIGNATURE or

FINGERPRINT


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COMPONENTS Light Source (Gas discharge lamps)

Sources of excitation radiant energy

XENON ARC LAMP

MERCURY Commonly use in filter fluorometers

Attenuator Controls light intensity

Primary filter Select wavelength that is best absorb by the solution to be measured

Cuvet Secondary filter

Passes the longer wavelengths of fluorescent lamp

Light detector (PM Tube) Readout device


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Advantage Specificity

selecting the optimal wavelength for both absorption andfluorescence.

Sensitivity 1000x more sensitive than spectrophotometric method

Disadvantage Sensitive to environmental changes

Affects by Quenching pH Temperature Chemical contaminants UV light changes


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Part of the chemical energy generated excitedintermediates that decay .to a ground state withthe emission of photons.

No excitation radiation is required and nomonochromators are needed because thechemiluminescene arises from one species

CHEMILUMINESCENCE reactions are oxidationreactions ofLUMINOL, ACRIDIUM ESTERS and

DIOXETANES characterized by rapid increase inintensity of emitted light followed by a gradualdecay.


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Advantage

Subpicomolar detection limits

Speed With flash type reactions, light is only measured for 10

seconds)

Ease of use (one step procedure)

Disadvantage Impurities can cause background signal that

degrades sensitivity and specificity


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Enhanced chemiluminescence techniquesincrease the chemiluminiescence efficiency

by including an enhancer system in thereaction of a chemiluminescent agent with anenzyme.~60 minutes compared to 30seconds time course for the light intensity of

conventional chemiluminescent reaction


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Determine the amount of scattered light bya particulate matter suspended in a turbid

solution Light scattering depends on wavelength and

particle size For measuring the amount of antigen-

antibody reaction complexes


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Determine the amount oflight blocked by aparticulate matter in a turbid solution.

The amount of light blocked by a suspensionof particles depends not only onconcentration but also on size.

For measuring abundant large particles

proteins and bacterial suspension


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Light amplification by stimulated emission ofradiation is based on the interaction of

radiant energy and suitably excited atoms ormolecules.


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GALVANIC CELLS

Electrodes are connected

There is spontaneous flow of electrons from theelectron of lower affinity(oxidation), theseelectrons pass through the external meter to

cathode (reduction), where OH- ions are liberated.

ELECTROLYTIC CELLS- when current is force tofloe through the dead cells only by applying an

external electromotive force E.


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To rate half cell reaction, a specific electrodereaction is arbitrarily assigned 0.00V.

(standard hydrogen eectrode:H2 gas at 1atm) Every other reaction coupled with this

arbitrary zero reaction is either positive or

negative, depending on the relative affinityfor electrons.


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Measurement of differences in voltage (potential)between two electrodes in a solution for measuringanalyte concentration at a constant current

Electric potentials are produced at the interfacebetween a metal and ions of that metal in solution.Also, when a membrane semipermeable to that ionseparates different concentrations of an ion.

REFERENCE ELECTRODE Electrode with constant voltage

INDICATOR ELECTRODE Measuring electrode


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GLASS ELECTRODE first and mostcommon electrodes for measuring hydrogenion activity (pH or negative log of hydrogenion concentration)

Consist of bulb made of layers of hydratedand nonhydrated glass, which contains a

chloride ion buffer solution


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Electrochemical transducer capable of responding to onespecific ion.

Very sensitive and selective for the ion it measures Consist of a membrane or other barrier separating a

reference solution and a reference electrode from thesolution to be analyzed. Depends on membrane/barrier composition that

determines its ionic selectivity Gas electrode

Liquid membrane electrodes

Precipitate-impregnated membrane electrodes

Solid state electrodes

Gas electrodes

Enzyme electrodes


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BUFFER as known hydrogen ionconcentration

Silver/silver chloride

internal reference electrode

Saturated calomel electrode

External reference electrode


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pH electrode consist of a silver wire coatedwith AgCl, immersed into an internal soln of0.1 mmol/L HCl, and placed into a tube

containing special glass membrane tip The glass membranes are selectively

sensitive to H+ consist of lithium, cesium,lanthanum, barium or aluminum oxide

Potential difference between the internalsolution and test solution is measure as pHand read by voltmeter


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Should be

Reversible and obey the Nernst equation Exhibit a potential that is constant with time.

Return to its original potential after being

subjected to small currents

Exhibit little hysteries (lag with temperaturecycling)


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Generally consist of a metal and its salt in contact witha solution containing the same anion.

CALOMEL ELECTRODE- commonly used

A paste of predominant mercurous chloride, is in directcontact with metallic mercury in an electrolyte solution ofpotassium chloride.

Slow to reach a new stable voltage following temperaturechange and it is unstable above 80C

SILVER/SILVER CHLORIDE Can be used at temperature up to 275C

MERCURY SULFATE AND POTASSIUM SULFATE


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Set up at boundary between two dissimilarsolutions because of positive and negativeions diffusing across the boundary at unequalrates

POTASSIUM CHLORIDE Commonly used filling solution because K+ and Cl- have

nearly the same mobility


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Selection of ISE is determined by the reactionproduct of the immobilized enzyme

Ex:

Urease urea

Glucose oxidase glucose detection


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1. Inert metal electrodes in contact with a redox couple Hydrogen electrode

2. Metal electrodes that participate in redox reaction Ag/AgCl electrode

3. Membrane electrodes1. Solid materials

glass

2. Liquid materials Ion exchange electrodes Calcium ISE

3. Special membrane Gas-sensing Enzyme electrodes


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Measures the quantity of electricity (incoulombs) needed to convert an analyte to adifferent oxidation state

Coulomb is the quantity of electricity orcharge that is transported in 1 second by aconstant current of 1 ampere for t second.

Used to measure chloride ion in serum,plasma , CSF and sweat samples.


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pH electrode contained within a plastic jacket Filled with sodium bicarbonate buffer and has

a gas-permeable membrane (teflon orsilicone) across its opening


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Measurement of the current flow producedby an oxidation- reduction reaction.

For chloride measurement (coloumetry-amperometry)


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Potential is applied to an electrochemical celland the resulting current is measured

ADVANTAGE: sensitivity and capability formulti element measurement

Analytes can be detected in parts per billionrange

ANODIC STRIPPING VOLTAMMETRY Electrochemical technique used to measure heavy

metals such as lead


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CONDUCTANCE

Electrolytic conductivity is a measure of the ability

of a solution to carry an electric current

IMPEDANCE

Based on the change in electrical resistance across

an aperture when a particle in conductive liquid

passes through this aperture Used in hematology laboratory to enumerate

leukocytes, erythrocytes and platelets


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Performed similarly to other electrophoresis methods,except that the separating molecules migrate through pHgradient

deal for separating .proteins of identical sizes but with

different net charges. Protein s move in the electric field until they reach a pHequal to their isoelectric point.

Ph gradient is made by adding acid to anodic side andadding base to cathode area.

ADV: ability to resolve mixture of proteins For measuring serum acid phosphatase isoenzymes,

detection of oligoclonal immunoglobulin bands in CSF andisoenzymes of creatine kinase and alkaline phosphatase inserum.


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ELECTROPHORESIS

Separation of charged compounds based on their

electrical charge

Cations go towards anode, anions go towardscathode

The greater the net charges of a dissolve

compound, the faster it moves through hesolution toward the opposite charged electrode.


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Measures the absorbance of the stain on asupport medium.

COMPONENTS

Light source

Monochromator

Movable carriage

Optical system

Photodetector


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Migration of charged solutes or particles in anelectric field

IONTROPHORESIS

Refers to the migration of small ions ZONE ELECTROPHORESIS Migration of charged macromolecules in a porous

support medium such as paper, cellulose acetate or

agarose gel film ELECTROPHORETOGRAM

Result of zone electrophoresis

Consist of sharply separated zone of macromolecules


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Driving force (electrical power) Support medium Buffer Sample Detecting system


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Charged particles migrate toward the oppositecharged electrode

Velocity of migration depends on: Net charge of particle

Size and shape of the particle Strength of the electric field Chemical and physical properties of the supporting

medium

Electrophoretic temperature

Rate of migration is directly proportional to the netcharge of the particle and inversely proportional to itssize and the viscosity of the buffer


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Cellulose acetate Formed by treating cellulose acetylated with acetic anhydride Dry, brittle, film composed of about 80% air space. Also used in isoelectric focusingjm

Agarose gel

Purified fraction of agar, it is neutral and does not produce electroendosmosis Requires small amount of sample (approx 2mL) Does not bind protein therefore migration is not affected

Polyacrylamide gel Separation of protein on the basis of charge and molecular size Separate serum into 20 or more fractions rather than the usual five fraction.

Widely used to study individual proteins Starch gel

Separates protein on the basis of surface charge and molecular size Not widely use because of technical difficulty in preparing gel.


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Separation is performed in narrow-bore fused silicacapillaries (inner diameter 2575 nm)

Concept: electro-osmotic flow (EOF) EOF is the bulk flow of liquid toward the cathode

upon application of electric field and it issuperimposed on electrophoretic migration. Cation migrate faster because both EOF and

electrophoretic attraction are towards cathode. For separation, quantitation and determination of

molecular weights of proteins and peptides, analysisof PCR products, analysis of organic ions, organicacids, pharmaceuticals, optical isomers and drugs ofabuse in serum and urine.


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The movement of buffer ions an solventrelative to the fixed support

Support media: paper, cellulose acetate andagar gel

Hydroxyl ion remain fixed while free positiveions move toward the cathode.


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Separation method based on differentinteraction of the specimen compounds withthe mobile phase and the stationary phase ascompound travel through a support medium.

RETENTION TIME(tR) Time it takes a compound to elute


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MOBILE PHASE Gas or liquid

Carries the complex mixture (sample)

STATIONARY PHASE Solid or liquid

Through which the mobile phase flows COLUMN Holding the stationary phase

SEPARATED COMPONENTS eluate


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Adsorption AKA liquid-solid chromatography Based on the competition between the sample and the mobile phase

for absorption sites on the solid stationary phase Molecules that are most soluble in the mobile phase , move fastest

Partition AKA liquid-liquid chromatography Separation of solute based on relative solubility in an organic

(nonpolar) solvent and aqueous(polar) solvent

Normal phase mobile solvent is less polar than the stationary solvent Reverse phase mobile solvent is more polar

Applicable to any substance that maybe distributed between twoliquid

Works best in nonionic compound


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Steric exclusion

Variation of liquid-solid chromatography

Separate molecules on the basis of the size and shape

Ion exchange

Solute mixture are separated by virtue of themagnitude and charge of ionic species.

Stationary phase is a resin consisting of largepolymers of substituted benzene, silicates or cellulosederivatives, with charge functional groups


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THINLAYER CHROMATOGRAPHY

Thin layer of sorbent , such as alumina , silica gel,

cellulose or cross linked dextran, is uniformly

coated on a glass or plastic plate

Most commonly used as semiquantitative

screening test


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Uses pressure for fast separations, controlledtemperature, in-line detectors and gradientelution techniques

PUMPS Forces the mobile phase through the column at a

much greater velocity than that accomplished bygravity-flow columns and includes pneumatic,syringe, reciprocating or hydraulic amplifier pumps.

MECHANICAL RECIPROCATING PUMP

Multihead pump with two or more reciprocating pistons.


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COLUMNS

Long stainless steel where the stationary phase is

packed

SILICA GEL most common material used forpacking

Stable and can be used in different ways.

Reverse-phase HPLC Stationary phase is nonpolar molecules(octadecyl C-18

hydrocardbon) bonded to silica gel particles.


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SAMPLE INJECTORS Small syringe Loop injector best and widely used

High reproducibility and used at high temperature.

DETECTORS Monitor the eluate as it leaves the column and produce an

electronic signal proportional to the concentration of eachseparated component

RECORDERS

Used to record detector signal versus the time the mobilephase passed through the instrument, starting from thetime of injection.

CHROMATOGRAM -


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Separate mixture of compounds hat arevolatile or can be made volatile.

GAS-SOLID CHROMATOGRAPHY (GSC)

solid stationary phase

GAS-LIQUID CHROMATOGRAPHY (GLC)

With non volatile liquid stationary phase.

Commonly used in clinical laboratories.


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ADVANTAGE

Increase the number of tests to be performed in a

given period

Minimizes variation of result from onelaboratorian to another

Eliminates the potential error in manual analyses

such as pipetting, calculation and transcript ofresult


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CONTINUOUS FLOW ANALYZER Liquids are pump through a system of continuous tubing

Samples flow through a common reaction vessel orpathway.

Air bubbles at regular intervals serves as separating andcleaning media

Mixture of sample and reagent takes place using a glasscoil inserted into flow path

A heating bath maintains the required temperature ofthe reaction to allow complete color development-reaction rate is controlled by temperature

Ex Simultaneous multiple analyzer (SMA), technicon


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CENTRIFUGAL ANALYZER Use the force generated by centrifugation to transfer

specimen and reagents

Liquids are placed in separate cuvets for measurement atthe perimeter of a spinning rotor (1000rpm)

It uses acceleration and deceleration of the rotor totransfer the reagents and sample from one chamber toanother

For mixing, centrifugal force or rotor is utilized orbubbling of air

Major advantage: Batch analysis

Ex Cobas- Bio (Roche), IL Monarch


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DISCRETE ANALYZER Most popular and versatile analyzer Employs variety of syringe and pipettes to aspirate and dispense sample and

reagents Positive liquid-displacement pipettes are used for sampling

Capable of running multiple-test-one-sample at-a-time. Each sample-reagent mixture handles separately in its own vessel Has Random access capability that allows STAT samples to be easily

accessed. For mixing, magnetic driven teflon stirring bar located in the bottom of the

reaction chamber is used in Beckman ASTRA For dry slide technology (reflectance photometry, the spreading layer permits

a rapid uniform spreading layer over the reagent layer. REFLECTANCE PHOTOMETRY- measure the light reflected from solid surfaces.

EX: Vitros, dimension Dade, Beckman ASTRA System, Hitachi, Bayer Advia Roche CobasIntegra 800, Roche anlaysis P module, ACA star (Dade)


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BATCH TESTING All samples are loaded at the same time, and singles test is conducted

on each sample PARALLEL TESTING

More than one test is analyzed concurrently on a given clinical

specimen RANDOM ACCESS TESTING

Any test can be performed on any sample in any sequence SEQUENTIAL TESTING

Multiple tests analyzed one after another on a given specimen OPEN REAGENT SYSTEM

A system other than manufacturers reagent can be utilized formeasurement

CLOSE REAGENT SYSTEM A system where the operator can only used the manufacturer

reagents.


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DONT FORGET TO READ YOUR BOOKS!

KEEP CALMANDPRAY

GODBLESS! =)

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