Gel permeation chromatography (GPC) is a size-exclusion chromatography technique used to separate macromolecules based on their hydrodynamic size. It works by passing a sample mixture in solution through a column containing porous gel beads, allowing smaller molecules to enter the pores while larger ones are excluded. Components are then eluted and detected based on their size, providing information about molecular weight distribution. Key components of GPC include the stationary phase gel beads, mobile phase solvent, pump, detectors like UV/RI, and column. It is commonly used to analyze polymers and biopolymers.
ION EXCHANGE CHROMATOGRAPHY
ByM.Vharshini
B.Sc. Bio Medical Science
Sri Ramachandra University
ION EXCHANGE CHROMATOGRAPHY
Ion-exchange chromatography is a process that allows the separation of ions and polar molecules based on their affinity to the ion exchanger.
It can be used for almost any kind of charged molecule including large proteins, small nucleotides and amino acids.
Cations or Anions can be separated using this method.
PRINCIPLE
It is based on the reversible electrostatic interaction of ions with the separation matrix (i.e.)
The separation occurs by reversible exchange of ions between the ions present in the solution and those present in the ion exchange resin.
CLASSIFICATION OF RESINS
According to the chemical nature they classified as-
1. Strong cation exchange resin
2. Weak cation exchange resin
3. Strong anion exchange resin
4. Weak anion exchange resin
According to the Source they can -
Natural resins : Cation - Zeolytes, Clay
Anion - Dolomite
Synthetic resins: Inorganic & Organic resins
◘Organic resins are polymeric resin matrix.
The resin composed of –
Polystyrene (sites for exchangeable functional groups)
Divinyl benzene(Cross linking agent)-offers stability.
Ion exchange resin should have following requirements
»It must be chemically stable.
»It should be insoluble in common solvents.
» It should have a sufficient degree of cross linking.
»The swollen resin must be denser than water.
»It must contain sufficient no. of ion exchange groups.
Physical properties of ion exchange resins
Cross linking:
It affects swelling & strength & solubility
Swelling:
When resin swells, polymer chain spreads apart
Polar solvents → swelling
Non-polar solvents → contraction
Swelling also affected electrolyte concentration.
Particle size and porosity
Increase in surface area & decrease in particle size will increase the rate of ion exchange.
Regeneration
Cation exchange resin are regenerated by treatment with acid, then washing with water.
Anion exchange resin are regenerated by treatment with NaOH, then washing with water until neutral.
EXPERIMENTAL SETUP OF ION EXCHANGE CHROMATOGRAPHY
Metrohm 850 Ion chromatography system
Instrumentation of ion exchange chromatography
PRACTICAL REQUIREMENTS
1.Column
» glass, stainless steel or polymers
2.Packing the column
» Wet packing method:
A slurry is prepared of the eluent with the stationary phase powder and then carefully poured into the column. Care must be taken to avoid air bubbles.
3.Application of the sample
After packing, sample is added to the top of the stationary phase, use syringe or pipette.
This layer is usually topped with a small layer of sand or with cotton or glass wool to protect the shape of the organic layer from the velocity of newly added eluent.
4.Mobile phase
Acids, alkalis, buffers…
6.Stationary phase
The ionic
Principle
Interferences
Instrumentation and
Applications
The principle of flame photometer
is based on the measurement of the emitted light intensity when a metal is introduced into the flame.
The wavelength of the colour gives information about the element and
the colour of the flame gives information about the amount of the element present in the sample.
Flame photometry is one of the branches of atomic absorption spectroscopy.
It is also known as flame emission spectroscopy.
Currently, it has become a necessary tool in the field of analytical chemistry. Used to
Determine the concentration of certain metal ions like
potassium,lithium, calcium, cesium etc. In flame photometer spectra the metal ions are used in the form of atoms.
(IUPAC) Committee on Spectroscopic Nomenclature has named this technique as flame atomic emission spectrometry (FAES). Principle of Flame photometer
The compounds of the alkali and alkaline earth metals (Group II) dissociate into atoms when introduced into the flame.
Some of these atoms further get excited to even higher levels. But these atoms are not stable at higher levels.
Hence, these atoms emit radiations when returning back to the ground state.
These radiations generally lie in the visible region of the spectrum.
Each of the alkali and alkaline earth metals has a specific wavelength. Instrumentation-Source of flame, Nebuliser, Monochromator(Prism monochromator, Grating monochromators)DETECTOR (
The radiation emitted by the elements is mostly in the visible region and measured by photo detector. Hence conventional detectors like photo voltaic cell or photo tubes or photomultiplier tube is used), READ OUT DEVICE
[The signal from the detector is shown as a response in the digital read out device. The readings are displayed in an arbitrary scale (% Flame Intensity).], working of flame photometer, Advantages and disadvantage of flame photometer, Errors /interference in Flame Photometry-Flame Temperature, chemical interference, Radiation interference
Application of flame photometry
In this slide contains principle, instrumentation, methodology, and application of gel chromatography.
Presented by: SATHEES CHANDRA (Department of pharmaceutical analysis).
RIPER, anantapur
SPECTROSCOPY is defined as the study of the interactions between radiations and matter as function of wavelength λ .
Interactions with particle radiation or a response of a material to an altering field
or varying frequency.
SPECTRUM : A plot of the response as a function of wavelength or more commonly frequency is referred to as spectrum.
SPECTROMETRY : It is measurement of these responses and an instrument which performs such measurements is a spectrophotometer or spectrograph, although
these terms are more limited in use to original field of optics from which the
concept sprang.
ION EXCHANGE CHROMATOGRAPHY
ByM.Vharshini
B.Sc. Bio Medical Science
Sri Ramachandra University
ION EXCHANGE CHROMATOGRAPHY
Ion-exchange chromatography is a process that allows the separation of ions and polar molecules based on their affinity to the ion exchanger.
It can be used for almost any kind of charged molecule including large proteins, small nucleotides and amino acids.
Cations or Anions can be separated using this method.
PRINCIPLE
It is based on the reversible electrostatic interaction of ions with the separation matrix (i.e.)
The separation occurs by reversible exchange of ions between the ions present in the solution and those present in the ion exchange resin.
CLASSIFICATION OF RESINS
According to the chemical nature they classified as-
1. Strong cation exchange resin
2. Weak cation exchange resin
3. Strong anion exchange resin
4. Weak anion exchange resin
According to the Source they can -
Natural resins : Cation - Zeolytes, Clay
Anion - Dolomite
Synthetic resins: Inorganic & Organic resins
◘Organic resins are polymeric resin matrix.
The resin composed of –
Polystyrene (sites for exchangeable functional groups)
Divinyl benzene(Cross linking agent)-offers stability.
Ion exchange resin should have following requirements
»It must be chemically stable.
»It should be insoluble in common solvents.
» It should have a sufficient degree of cross linking.
»The swollen resin must be denser than water.
»It must contain sufficient no. of ion exchange groups.
Physical properties of ion exchange resins
Cross linking:
It affects swelling & strength & solubility
Swelling:
When resin swells, polymer chain spreads apart
Polar solvents → swelling
Non-polar solvents → contraction
Swelling also affected electrolyte concentration.
Particle size and porosity
Increase in surface area & decrease in particle size will increase the rate of ion exchange.
Regeneration
Cation exchange resin are regenerated by treatment with acid, then washing with water.
Anion exchange resin are regenerated by treatment with NaOH, then washing with water until neutral.
EXPERIMENTAL SETUP OF ION EXCHANGE CHROMATOGRAPHY
Metrohm 850 Ion chromatography system
Instrumentation of ion exchange chromatography
PRACTICAL REQUIREMENTS
1.Column
» glass, stainless steel or polymers
2.Packing the column
» Wet packing method:
A slurry is prepared of the eluent with the stationary phase powder and then carefully poured into the column. Care must be taken to avoid air bubbles.
3.Application of the sample
After packing, sample is added to the top of the stationary phase, use syringe or pipette.
This layer is usually topped with a small layer of sand or with cotton or glass wool to protect the shape of the organic layer from the velocity of newly added eluent.
4.Mobile phase
Acids, alkalis, buffers…
6.Stationary phase
The ionic
Principle
Interferences
Instrumentation and
Applications
The principle of flame photometer
is based on the measurement of the emitted light intensity when a metal is introduced into the flame.
The wavelength of the colour gives information about the element and
the colour of the flame gives information about the amount of the element present in the sample.
Flame photometry is one of the branches of atomic absorption spectroscopy.
It is also known as flame emission spectroscopy.
Currently, it has become a necessary tool in the field of analytical chemistry. Used to
Determine the concentration of certain metal ions like
potassium,lithium, calcium, cesium etc. In flame photometer spectra the metal ions are used in the form of atoms.
(IUPAC) Committee on Spectroscopic Nomenclature has named this technique as flame atomic emission spectrometry (FAES). Principle of Flame photometer
The compounds of the alkali and alkaline earth metals (Group II) dissociate into atoms when introduced into the flame.
Some of these atoms further get excited to even higher levels. But these atoms are not stable at higher levels.
Hence, these atoms emit radiations when returning back to the ground state.
These radiations generally lie in the visible region of the spectrum.
Each of the alkali and alkaline earth metals has a specific wavelength. Instrumentation-Source of flame, Nebuliser, Monochromator(Prism monochromator, Grating monochromators)DETECTOR (
The radiation emitted by the elements is mostly in the visible region and measured by photo detector. Hence conventional detectors like photo voltaic cell or photo tubes or photomultiplier tube is used), READ OUT DEVICE
[The signal from the detector is shown as a response in the digital read out device. The readings are displayed in an arbitrary scale (% Flame Intensity).], working of flame photometer, Advantages and disadvantage of flame photometer, Errors /interference in Flame Photometry-Flame Temperature, chemical interference, Radiation interference
Application of flame photometry
In this slide contains principle, instrumentation, methodology, and application of gel chromatography.
Presented by: SATHEES CHANDRA (Department of pharmaceutical analysis).
RIPER, anantapur
SPECTROSCOPY is defined as the study of the interactions between radiations and matter as function of wavelength λ .
Interactions with particle radiation or a response of a material to an altering field
or varying frequency.
SPECTRUM : A plot of the response as a function of wavelength or more commonly frequency is referred to as spectrum.
SPECTROMETRY : It is measurement of these responses and an instrument which performs such measurements is a spectrophotometer or spectrograph, although
these terms are more limited in use to original field of optics from which the
concept sprang.
Gel chromatography, Introduction, Theory, Instrumentation, Applications .pptxVandana Devesh Sharma
Affinity chromatography- Content-Introduction
Theory
Instrumentation
Applications
Gel chromatography is a type of partition chromatography used for separating different sized molecules.
Gel chromatography is also called Gel permeation chromatography or gel filtration or gel exclusion, size exclusion, molecular- sieve chromatography.
The separation is based on the analyte molecular sizes since the gel behaves like a molecular sieve.
In size exclusion chromatography, the stationary phase is a porous matrix made up of compounds like
cross-linked polystyrene, cross-like dextrans, polyacrylamide gels, agarose gels, etc.
The gel structure being used contains pores of different diameters upto maximum size.
1.The test molecules are washed through a gel column and molecules larger than the largest pores in the gel are excluded from the gel structure.
2. Smaller molecules penetrate the gel and the extent of penetration depends on the molecular size----- This delay their movement through the column
This technique is used for the separation of proteins, polysaccharides, enzymes, and synthetic polymers. Instrumentation- A. Stationary phase- It is composed of semi-permeable, porous polymer gel beads with a well-defined range of pore sizes. eg. Dextran, Agarose, Acrylamide. 2. sample size and concentration- sample is applied in small volume (1-5% of the total bed volume).3. Column parameters- use long column, ratio of column diameter to column length (1:20 to :100). The method or steps used for gel preparation. 4. Choice of eluent/mobile phase- Buffers Ex- Phosphate buffer pH 7, NaCl solution, Ammonium acetate (CH3COO-NH4+ ), Ammonium bicarbonate (NH₄HCO₃) ethylenediamine acetate. 5. Effect of Flow rate- maintain with the help of pump. Elution carried out with buffer at optimal flow rate (Eg- 0.25-5ml/min) to give maximum resolution with optimal separation time.6. Separation of components from the sample-
Separation of component from mixture is achieved with the help of column. The retention volume (VR).7. Detection- Using UV absorption detectors. A graph of Elution Volume (ml) Vs Molecular weight. 7. Detection- Using UV absorption detectors. A graph of Elution Volume (ml) Vs Molecular weight. For calibration of the gel in column – Calibrators - (Proteins of known molecular weight. Procedure for gel filtration technique-1. Preparation of column- 2. Washing of the column- 3. Loading of the sample-4. Elution using mobile phase (buffers)5. Detection of compounds . Applications
Product polishing techniques in Downstream ProcessingErin Davis
This is a presentation based on gel permeation chromatography and dialysis.This mainly deals with the basic principle behind these techniques.and its working.The major components,advantages,disadvantages,applications are also mentioned in the same.Besides these the pictoric representation helps to understand the concept clearly.
This will be helpful to learn downstream processing techniques.
What is greenhouse gasses and how many gasses are there to affect the Earth.moosaasad1975
What are greenhouse gasses how they affect the earth and its environment what is the future of the environment and earth how the weather and the climate effects.
Richard's aventures in two entangled wonderlandsRichard Gill
Since the loophole-free Bell experiments of 2020 and the Nobel prizes in physics of 2022, critics of Bell's work have retreated to the fortress of super-determinism. Now, super-determinism is a derogatory word - it just means "determinism". Palmer, Hance and Hossenfelder argue that quantum mechanics and determinism are not incompatible, using a sophisticated mathematical construction based on a subtle thinning of allowed states and measurements in quantum mechanics, such that what is left appears to make Bell's argument fail, without altering the empirical predictions of quantum mechanics. I think however that it is a smoke screen, and the slogan "lost in math" comes to my mind. I will discuss some other recent disproofs of Bell's theorem using the language of causality based on causal graphs. Causal thinking is also central to law and justice. I will mention surprising connections to my work on serial killer nurse cases, in particular the Dutch case of Lucia de Berk and the current UK case of Lucy Letby.
Deep Behavioral Phenotyping in Systems Neuroscience for Functional Atlasing a...Ana Luísa Pinho
Functional Magnetic Resonance Imaging (fMRI) provides means to characterize brain activations in response to behavior. However, cognitive neuroscience has been limited to group-level effects referring to the performance of specific tasks. To obtain the functional profile of elementary cognitive mechanisms, the combination of brain responses to many tasks is required. Yet, to date, both structural atlases and parcellation-based activations do not fully account for cognitive function and still present several limitations. Further, they do not adapt overall to individual characteristics. In this talk, I will give an account of deep-behavioral phenotyping strategies, namely data-driven methods in large task-fMRI datasets, to optimize functional brain-data collection and improve inference of effects-of-interest related to mental processes. Key to this approach is the employment of fast multi-functional paradigms rich on features that can be well parametrized and, consequently, facilitate the creation of psycho-physiological constructs to be modelled with imaging data. Particular emphasis will be given to music stimuli when studying high-order cognitive mechanisms, due to their ecological nature and quality to enable complex behavior compounded by discrete entities. I will also discuss how deep-behavioral phenotyping and individualized models applied to neuroimaging data can better account for the subject-specific organization of domain-general cognitive systems in the human brain. Finally, the accumulation of functional brain signatures brings the possibility to clarify relationships among tasks and create a univocal link between brain systems and mental functions through: (1) the development of ontologies proposing an organization of cognitive processes; and (2) brain-network taxonomies describing functional specialization. To this end, tools to improve commensurability in cognitive science are necessary, such as public repositories, ontology-based platforms and automated meta-analysis tools. I will thus discuss some brain-atlasing resources currently under development, and their applicability in cognitive as well as clinical neuroscience.
Earliest Galaxies in the JADES Origins Field: Luminosity Function and Cosmic ...Sérgio Sacani
We characterize the earliest galaxy population in the JADES Origins Field (JOF), the deepest
imaging field observed with JWST. We make use of the ancillary Hubble optical images (5 filters
spanning 0.4−0.9µm) and novel JWST images with 14 filters spanning 0.8−5µm, including 7 mediumband filters, and reaching total exposure times of up to 46 hours per filter. We combine all our data
at > 2.3µm to construct an ultradeep image, reaching as deep as ≈ 31.4 AB mag in the stack and
30.3-31.0 AB mag (5σ, r = 0.1” circular aperture) in individual filters. We measure photometric
redshifts and use robust selection criteria to identify a sample of eight galaxy candidates at redshifts
z = 11.5 − 15. These objects show compact half-light radii of R1/2 ∼ 50 − 200pc, stellar masses of
M⋆ ∼ 107−108M⊙, and star-formation rates of SFR ∼ 0.1−1 M⊙ yr−1
. Our search finds no candidates
at 15 < z < 20, placing upper limits at these redshifts. We develop a forward modeling approach to
infer the properties of the evolving luminosity function without binning in redshift or luminosity that
marginalizes over the photometric redshift uncertainty of our candidate galaxies and incorporates the
impact of non-detections. We find a z = 12 luminosity function in good agreement with prior results,
and that the luminosity function normalization and UV luminosity density decline by a factor of ∼ 2.5
from z = 12 to z = 14. We discuss the possible implications of our results in the context of theoretical
models for evolution of the dark matter halo mass function.
This pdf is about the Schizophrenia.
For more details visit on YouTube; @SELF-EXPLANATORY;
https://www.youtube.com/channel/UCAiarMZDNhe1A3Rnpr_WkzA/videos
Thanks...!
A brief information about the SCOP protein database used in bioinformatics.
The Structural Classification of Proteins (SCOP) database is a comprehensive and authoritative resource for the structural and evolutionary relationships of proteins. It provides a detailed and curated classification of protein structures, grouping them into families, superfamilies, and folds based on their structural and sequence similarities.
Cancer cell metabolism: special Reference to Lactate PathwayAADYARAJPANDEY1
Normal Cell Metabolism:
Cellular respiration describes the series of steps that cells use to break down sugar and other chemicals to get the energy we need to function.
Energy is stored in the bonds of glucose and when glucose is broken down, much of that energy is released.
Cell utilize energy in the form of ATP.
The first step of respiration is called glycolysis. In a series of steps, glycolysis breaks glucose into two smaller molecules - a chemical called pyruvate. A small amount of ATP is formed during this process.
Most healthy cells continue the breakdown in a second process, called the Kreb's cycle. The Kreb's cycle allows cells to “burn” the pyruvates made in glycolysis to get more ATP.
The last step in the breakdown of glucose is called oxidative phosphorylation (Ox-Phos).
It takes place in specialized cell structures called mitochondria. This process produces a large amount of ATP. Importantly, cells need oxygen to complete oxidative phosphorylation.
If a cell completes only glycolysis, only 2 molecules of ATP are made per glucose. However, if the cell completes the entire respiration process (glycolysis - Kreb's - oxidative phosphorylation), about 36 molecules of ATP are created, giving it much more energy to use.
IN CANCER CELL:
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
Unlike healthy cells that "burn" the entire molecule of sugar to capture a large amount of energy as ATP, cancer cells are wasteful.
Cancer cells only partially break down sugar molecules. They overuse the first step of respiration, glycolysis. They frequently do not complete the second step, oxidative phosphorylation.
This results in only 2 molecules of ATP per each glucose molecule instead of the 36 or so ATPs healthy cells gain. As a result, cancer cells need to use a lot more sugar molecules to get enough energy to survive.
introduction to WARBERG PHENOMENA:
WARBURG EFFECT Usually, cancer cells are highly glycolytic (glucose addiction) and take up more glucose than do normal cells from outside.
Otto Heinrich Warburg (; 8 October 1883 – 1 August 1970) In 1931 was awarded the Nobel Prize in Physiology for his "discovery of the nature and mode of action of the respiratory enzyme.
WARNBURG EFFECT : cancer cells under aerobic (well-oxygenated) conditions to metabolize glucose to lactate (aerobic glycolysis) is known as the Warburg effect. Warburg made the observation that tumor slices consume glucose and secrete lactate at a higher rate than normal tissues.
Professional air quality monitoring systems provide immediate, on-site data for analysis, compliance, and decision-making.
Monitor common gases, weather parameters, particulates.
Nutraceutical market, scope and growth: Herbal drug technologyLokesh Patil
As consumer awareness of health and wellness rises, the nutraceutical market—which includes goods like functional meals, drinks, and dietary supplements that provide health advantages beyond basic nutrition—is growing significantly. As healthcare expenses rise, the population ages, and people want natural and preventative health solutions more and more, this industry is increasing quickly. Further driving market expansion are product formulation innovations and the use of cutting-edge technology for customized nutrition. With its worldwide reach, the nutraceutical industry is expected to keep growing and provide significant chances for research and investment in a number of categories, including vitamins, minerals, probiotics, and herbal supplements.
THE IMPORTANCE OF MARTIAN ATMOSPHERE SAMPLE RETURN.Sérgio Sacani
The return of a sample of near-surface atmosphere from Mars would facilitate answers to several first-order science questions surrounding the formation and evolution of the planet. One of the important aspects of terrestrial planet formation in general is the role that primary atmospheres played in influencing the chemistry and structure of the planets and their antecedents. Studies of the martian atmosphere can be used to investigate the role of a primary atmosphere in its history. Atmosphere samples would also inform our understanding of the near-surface chemistry of the planet, and ultimately the prospects for life. High-precision isotopic analyses of constituent gases are needed to address these questions, requiring that the analyses are made on returned samples rather than in situ.
2. Chromatography is an important biophysical technique that enables the
separation, identification, and purification of the components of a mixture for
qualitative and quantitative analysis.
Chromatography Types
1. Gas Chromatography.
2. High Performance Liquid Chromatography.
3. Gel Permeation Chromatography.
2
4. Discovery of GPC
• İnvented in 1955 by Grant Henry Lathe and Colin R Ruthven, working at
Queen Charlotte's Hospital, London.
• Lathe and Ruthven used starch gels as the matrix.
• Jerker Porath and Per Flodin later introduced dextran gels ,agarose and
polyacrylamide.
• J. C. Moore of the Dow Chemical Company - preparation of (GPC) columns
based on cross-linked polystyrene
4
5. Components of Gel Permeation Chromatography
1.Stationary Phase
2.The Mobile Phase
3.The Columns
4.The Pump
5.Detectors
5
6. Applications of GPC
• For the analysis of large molecules such as proteins or polymers
• To analyze the molecular weight distribution of organic-soluble polymers.
• Other technique should not be confused with gel electrophoresis, where an electric
field is used to "pull" or "push" molecules through the gel depending on their
electrical charges.
• The amount of time a solute remains within a pore is dependent on the size of the pore.
Larger solutes will have access to a smaller volume and vice versa.
• A smaller solute will remain within the pore for a longer period of time compared to a
larger solute.
6
7. Applications of GPC
• To examine the stability and characteristics of natural organic matter in
water.
• Widely utilized to study natural organic material.
7
8. GPC Theory
• Molecules in solution are separated by their size or molecular weight.
• Applied to large molecules or macromolecular complexes such as proteins and
industrial polymers.
• Organic solvent is used as a mobile phase to transport the sample through the column.
• Column is packed with fine, porous beads, composed of dextran, agarose,
or polyacrylamide polymers.
• The pore sizes of these beads are used to estimate the dimensions of macromolecules.
8
9. GPC Theory
• Works by trapping smaller molecules in the pores of the adsorbent
("stationary phase") in the column which typically consists of a hollow tube
tightly packed with micron-scale polymer beads containing pores of different
size.
• The larger the particles, the faster the elution. The larger molecules simply
pass by the pores because those molecules are too large to enter the pores .
• Widely used polymer characterization method because of its ability to
provide good molar mass distribution (Mw) results for polymers.
9
22. Stationary phase
• It is composed of semi-permeable, porous polymer gel beads with a well-defined range of
pore sizes with the following properties:
1. Chemically inert
2. Mechanically stable
3. With ideal and homogeneous porous structure (wide pore size give low resolution).
4. A uniform particle and pore size
• EXAMPLE : Dextran (Sephadex) gel: An α 1-6-polymer of glucose natural gel.
• Agarose gel: A 1,3 linked β-D-galactose and 1,4 linked 3,6-anhydro-α, L-galactose natural gel.
• Acrylamide gel: A polymerized acrylamide, a synthetic gel.
22
23. Mobile phase (Eluent )
• Composed of a liquid used to dissolve the bio-molecules to make the mobile phase
permit high detection response and wet the packing surface.
• Good solvent for the polymer, should permit high detector response from the
polymer.
• Common eluents for polymers that dissolve at room temperature.
• Tetrahydrofuran (THF), o-dichlorobenzene and trichlorobenzene at 130–150 °C for
crystalline polyalkynes and m-cresol.
• o-chlorophenol at 90 °C for crystalline condensation polymers such
as polyamides and polyesters.
23
24. Pump
• There are two types of pumps available for uniform delivery of relatively
small liquid volumes for GPC:
1. piston pumps
2. peristaltic pumps
24
27. Detector
• Detector types can be divided into two main categories.
1. Concentration sensitive detectors which includes UV
absorption, differential refractometer (DRI) or refractive index
(RI) detectors, infrared (IR) absorption and density detectors.
2. Molecular weight sensitive detectors, which include low angle
light scattering detectors (LALLS) and multi angle light
scattering (MALLS).
27
28. Detector
• The most sensitive detector is the differential UV photometer
and the most common detector is the differential refractometer
(DRI).
• When characterizing copolymer, it is necessary to have two
detectors in series.
• For accurate determinations of copolymer composition at least
two of those detectors should be concentration detectors.
• The determination of most copolymer compositions is done
using UV and RI detectors, although other combinations can be
used.
28
30. Column
• Columns mostly made from hydrophilic gels
of dextran, agarose or polyacrylamide
• The column used for GPC is filled with a microporous packing
material called gel.
30
31. Advantages of GPC
• Short analysis time.
• Well defined separation.
• Narrow bands and good sensitivity.
• There is no sample loss.
• The small amount of mobile phase required.
• The flow rate can be set.
• good separation of large molecules from the small molecules with a
minimal volume of eluate
• determining the molecular weight of polymer macromolecules.
• The separation is based on the analyte molecular sizes since the gel behaves
like a molecular sieve.
31
32. Disadvantages of Gel Permeation chromatography
• The number of peaks that can be resolved within the short time frame of a
GPC run is small.
• For a satisfactory resolution of peaks, GPC as a technique needs at least a
10% difference in molecular weight.
• The molecular masses of most of the polymer chains are too close together
for the GPC separation to produce anything other than large peaks.
• For polymers it needs filtration prior to use to prevent dust and other
particulates from destroying the columns and interfering with the detectors.
• limited number of bands can be accommodated because the time scale of
the chromatogram is short, as 10% difference in molecular mass to have a
good resolution.
• This relative data can be used to calculate molecular weights within 5%
precision if comparable criteria are used.
• To calibrate the GPC, polystyrene standards with disparities of less than 1.2
are commonly used.
32