The Detailed Theory and instrumentation of Both Amperometry and Biamperometric analysis is given with Titration curves and Applications.
Medha Thakur (M.Sc Chemistry)
This Powerpoint presentation helps us to know the basic working principles, instrumentation an advantage of super critical fluid chromatography.
Contact Details:
Anbu Dinesh Jayakumar
M.Pharmacy ( Pharmaceutical Chemistry)
Sri Ramakrishna Institute of Paramedical Sciences, Coimbatore
Mobile : 8838404664 / 8608890121( Whatsapp)
Email: anbudinesh007@gmail.com
The Detailed Theory and instrumentation of Both Amperometry and Biamperometric analysis is given with Titration curves and Applications.
Medha Thakur (M.Sc Chemistry)
This Powerpoint presentation helps us to know the basic working principles, instrumentation an advantage of super critical fluid chromatography.
Contact Details:
Anbu Dinesh Jayakumar
M.Pharmacy ( Pharmaceutical Chemistry)
Sri Ramakrishna Institute of Paramedical Sciences, Coimbatore
Mobile : 8838404664 / 8608890121( Whatsapp)
Email: anbudinesh007@gmail.com
fluid chromatography (SFC) can be used on an analytical
scale.
It is a combination of High performance liquid chromatography (HPLC)
and Gas chromatography (GC).
It can be used with non-volatile and thermally labile analytes.
It can be used with the universal flame ionization detector.
It is important to producing narrower peaks due to rapid diffusion.
It is important for the chiral separations and analysis of high-molecularweight
hydrocarbons.
Supercritical fluids are suitable as a substitute for organic solvents in a
range of industrial and laboratory processes.
fluid chromatography (SFC) can be used on an analytical
scale.
It is a combination of High performance liquid chromatography (HPLC)
and Gas chromatography (GC).
It can be used with non-volatile and thermally labile analytes.
It can be used with the universal flame ionization detector.
It is important to producing narrower peaks due to rapid diffusion.
It is important for the chiral separations and analysis of high-molecularweight
hydrocarbons.
Supercritical fluids are suitable as a substitute for organic solvents in a
range of industrial and laboratory processes.
No need to wonder how the best on SlideShare do it. The Masters of SlideShare provides storytelling, design, customization and promotion tips from 13 experts of the form. Learn what it takes to master this type of content marketing yourself.
10 Ways to Win at SlideShare SEO & Presentation OptimizationOneupweb
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SlideShares that inform, inspire and educate attract the most views. Beyond that, ideas for what you can upload are limitless. We’ve selected a few popular examples to get your creative juices flowing.
Examines the health and social effects of ACEs throughout the lifespan among 17,421 members of the Kaiser Health Plan in San Diego County.
Involving those who don’t yet realize that they are working on issues that represent the “downstream” wreckage of child abuse and neglect--and other adverse childhood experiences--in the effort to bridge the chasm.
Exportação de café verde do Brasil em janeiro soma 2,38 mi sacas, diz Cecafé
As exportações de café verde do Brasil em janeiro somaram 2,38 milhões de sacas de 60 quilos, ante 2,53 milhões de sacas no mesmo mês de 2016, disse o Conselho dos Exportadores de Café do Brasil (Cecafé) em relatório mensal nesta quinta-feira.
As exportações de café arábica em janeiro totalizaram 2,36 milhões de sacas, ante 2,46 milhões no mesmo mês do ano passado, enquanto as exportações de robusta somaram 22,1 mil sacas, ante 78 mil sacas no igual período de 2016, informou o Cecafé.
Fonte: CECAFÉ (Por Laís Martins)
Comunicado: brasileiro José Sette é escolhido como novo diretor-executivo da OICLuiz Valeriano
O brasileiro José Sette foi escolhido nesta sexta-feira, 17, para ficar à frente da Organização Internacional do Café (OIC), que tem sede em Londres. Nos últimos dias, ele disputava a vaga com mais cinco concorrentes, mas o processo teve início com uma corrida entre nove países. Nesta última etapa, além do Brasil, também concorriam candidatos do México, Peru, Suíça e Indonésia.
Durante uma semana de avaliação, os candidatos fizeram apresentações e também responderam a perguntas dos representantes dos 77 países que compõem a OIC. O processo desta vez foi presidido pela delegação dos Estados Unidos – as funções são rotativas na instituição.
“A simple and versatile analytical technology for automating wet chemical analysis, based on the physical and chemical manipulation of a dispersed sample zone formed from the injection of the sample into a flowing carrier stream and detection downstream”
This ppt describes the auto analyser which is used in biochemistry department in hospitals for analysing the composition of various constituents in the blood and other body fluids.
HPLC- Introduction, Theory, Instrumentation, Advantage, Applications
High-performance liquid chromatography or commonly known as HPLC, is an analytical technique used to separate, identify or quantify each component in a mixture.
The mixture is separated using the basic principle of column chromatography and then identified and quantified by spectroscopy.
In the 1960s, the column chromatography LC with its low-pressure suitable glass columns was further developed to the HPLC with its high-pressure adapted metal columns.
HPLC is thus basically a highly improved form of column liquid chromatography. Instead of a solvent being allowed to drip through a column under gravity, Solvent is forced through under high pressures of up to 400 atmospheres.
Principle
The separation principle of HPLC is based on the distribution of the analyte (sample) between a mobile phase (eluent) and a stationary phase (packing material of the column). Depending on the chemical structure of the analyte, the molecules are retarded while passing the stationary phase.
Instrumentation
1.Solvent reservoir and degassing system
2. Pumping System (Screw- driven syringe pump, Reciprocating pump, Pneumatic or constant- pressure pump)
3. Sample injection system(Septum injectors, Stop flow septum- less injection, Micro- volume sampling valves)
4. Columns- (1. Guard columns 2.separating column)
5. Detectors( The commonly used detectors in HPLC are
Bulk property detectors- examples
1. Refractive-index detectors
2. Conductivity detectors
Solute property detectors- Examples
1. UV detectors
2. Fluorescence detectors
Multipurpose detectors- Example-
1. Perkin-Elmer 3D system (UV absorption+ fluorescence + conductometric detection altogethers)
Electrochemical Detectors- Examples
1.Amperometric, 2. Coulometric detectors)
6. Recorder( There are various types of data processors; from a simple system consisting of the in-built printer and word processor while those with software that are specifically designed for an LC system which not only data acquisition but features, like peak-fitting baseline correction, automatic concentration calculation, molecular weight determination, etc.) Type of HPLC- Normal phase, Reverse Phase, ion exchange, size exclusion, Applications-Stability study- eg Atropin
Bioassays- HPLC is commonly used for the bioassay and analysis of peptide harmones and some antibiotics- cotrimoxazole, penicillins, sulphates and chloramphenicol
In cosmetic industries- used for analyzing the quality of various cosmetic products such as lipsticks, gels, creams etc
Isolation of Natural pharmaceutically Active Compounds– use in the isolation of different type of Alkaloids and Glycosides ( analysis of cinchona, liquorice, ergot extracts and digitalis.)
Control of microbiological processes- HPLC is used in analyse antibiotics (eg. Tetracyclines, chloramphenicol, strptomycin and penicillins )
Assay of cephalosporins
Advantage, Limitation
Salas, V. (2024) "John of St. Thomas (Poinsot) on the Science of Sacred Theol...Studia Poinsotiana
I Introduction
II Subalternation and Theology
III Theology and Dogmatic Declarations
IV The Mixed Principles of Theology
V Virtual Revelation: The Unity of Theology
VI Theology as a Natural Science
VII Theology’s Certitude
VIII Conclusion
Notes
Bibliography
All the contents are fully attributable to the author, Doctor Victor Salas. Should you wish to get this text republished, get in touch with the author or the editorial committee of the Studia Poinsotiana. Insofar as possible, we will be happy to broker your contact.
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.
The ability to recreate computational results with minimal effort and actionable metrics provides a solid foundation for scientific research and software development. When people can replicate an analysis at the touch of a button using open-source software, open data, and methods to assess and compare proposals, it significantly eases verification of results, engagement with a diverse range of contributors, and progress. However, we have yet to fully achieve this; there are still many sociotechnical frictions.
Inspired by David Donoho's vision, this talk aims to revisit the three crucial pillars of frictionless reproducibility (data sharing, code sharing, and competitive challenges) with the perspective of deep software variability.
Our observation is that multiple layers — hardware, operating systems, third-party libraries, software versions, input data, compile-time options, and parameters — are subject to variability that exacerbates frictions but is also essential for achieving robust, generalizable results and fostering innovation. I will first review the literature, providing evidence of how the complex variability interactions across these layers affect qualitative and quantitative software properties, thereby complicating the reproduction and replication of scientific studies in various fields.
I will then present some software engineering and AI techniques that can support the strategic exploration of variability spaces. These include the use of abstractions and models (e.g., feature models), sampling strategies (e.g., uniform, random), cost-effective measurements (e.g., incremental build of software configurations), and dimensionality reduction methods (e.g., transfer learning, feature selection, software debloating).
I will finally argue that deep variability is both the problem and solution of frictionless reproducibility, calling the software science community to develop new methods and tools to manage variability and foster reproducibility in software systems.
Exposé invité Journées Nationales du GDR GPL 2024
DERIVATION OF MODIFIED BERNOULLI EQUATION WITH VISCOUS EFFECTS AND TERMINAL V...Wasswaderrick3
In this book, we use conservation of energy techniques on a fluid element to derive the Modified Bernoulli equation of flow with viscous or friction effects. We derive the general equation of flow/ velocity and then from this we derive the Pouiselle flow equation, the transition flow equation and the turbulent flow equation. In the situations where there are no viscous effects , the equation reduces to the Bernoulli equation. From experimental results, we are able to include other terms in the Bernoulli equation. We also look at cases where pressure gradients exist. We use the Modified Bernoulli equation to derive equations of flow rate for pipes of different cross sectional areas connected together. We also extend our techniques of energy conservation to a sphere falling in a viscous medium under the effect of gravity. We demonstrate Stokes equation of terminal velocity and turbulent flow equation. We look at a way of calculating the time taken for a body to fall in a viscous medium. We also look at the general equation of terminal velocity.
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.
Slide 1: Title Slide
Extrachromosomal Inheritance
Slide 2: Introduction to Extrachromosomal Inheritance
Definition: Extrachromosomal inheritance refers to the transmission of genetic material that is not found within the nucleus.
Key Components: Involves genes located in mitochondria, chloroplasts, and plasmids.
Slide 3: Mitochondrial Inheritance
Mitochondria: Organelles responsible for energy production.
Mitochondrial DNA (mtDNA): Circular DNA molecule found in mitochondria.
Inheritance Pattern: Maternally inherited, meaning it is passed from mothers to all their offspring.
Diseases: Examples include Leber’s hereditary optic neuropathy (LHON) and mitochondrial myopathy.
Slide 4: Chloroplast Inheritance
Chloroplasts: Organelles responsible for photosynthesis in plants.
Chloroplast DNA (cpDNA): Circular DNA molecule found in chloroplasts.
Inheritance Pattern: Often maternally inherited in most plants, but can vary in some species.
Examples: Variegation in plants, where leaf color patterns are determined by chloroplast DNA.
Slide 5: Plasmid Inheritance
Plasmids: Small, circular DNA molecules found in bacteria and some eukaryotes.
Features: Can carry antibiotic resistance genes and can be transferred between cells through processes like conjugation.
Significance: Important in biotechnology for gene cloning and genetic engineering.
Slide 6: Mechanisms of Extrachromosomal Inheritance
Non-Mendelian Patterns: Do not follow Mendel’s laws of inheritance.
Cytoplasmic Segregation: During cell division, organelles like mitochondria and chloroplasts are randomly distributed to daughter cells.
Heteroplasmy: Presence of more than one type of organellar genome within a cell, leading to variation in expression.
Slide 7: Examples of Extrachromosomal Inheritance
Four O’clock Plant (Mirabilis jalapa): Shows variegated leaves due to different cpDNA in leaf cells.
Petite Mutants in Yeast: Result from mutations in mitochondrial DNA affecting respiration.
Slide 8: Importance of Extrachromosomal Inheritance
Evolution: Provides insight into the evolution of eukaryotic cells.
Medicine: Understanding mitochondrial inheritance helps in diagnosing and treating mitochondrial diseases.
Agriculture: Chloroplast inheritance can be used in plant breeding and genetic modification.
Slide 9: Recent Research and Advances
Gene Editing: Techniques like CRISPR-Cas9 are being used to edit mitochondrial and chloroplast DNA.
Therapies: Development of mitochondrial replacement therapy (MRT) for preventing mitochondrial diseases.
Slide 10: Conclusion
Summary: Extrachromosomal inheritance involves the transmission of genetic material outside the nucleus and plays a crucial role in genetics, medicine, and biotechnology.
Future Directions: Continued research and technological advancements hold promise for new treatments and applications.
Slide 11: Questions and Discussion
Invite Audience: Open the floor for any questions or further discussion on the topic.
Seminar of U.V. Spectroscopy by SAMIR PANDASAMIR PANDA
Spectroscopy is a branch of science dealing the study of interaction of electromagnetic radiation with matter.
Ultraviolet-visible spectroscopy refers to absorption spectroscopy or reflect spectroscopy in the UV-VIS spectral region.
Ultraviolet-visible spectroscopy is an analytical method that can measure the amount of light received by the analyte.
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.
Comparing Evolved Extractive Text Summary Scores of Bidirectional Encoder Rep...University of Maribor
Slides from:
11th International Conference on Electrical, Electronics and Computer Engineering (IcETRAN), Niš, 3-6 June 2024
Track: Artificial Intelligence
https://www.etran.rs/2024/en/home-english/
Toxic effects of heavy metals : Lead and Arsenicsanjana502982
Heavy metals are naturally occuring metallic chemical elements that have relatively high density, and are toxic at even low concentrations. All toxic metals are termed as heavy metals irrespective of their atomic mass and density, eg. arsenic, lead, mercury, cadmium, thallium, chromium, etc.
2. FIA is an automated method in which a sample is injected into a
continuous flow of a carrier solution that mixes with other
continuously flowing solutions before reaching a detector
Precision is dramatically increased when FIA is used instead of
manual injections and as a result very specific FIA systems have
been developed for a wide array of analytical techniques.
Flow Injection evolved into Sequential Injection and Bead
Injection which are novel techniques based on computer
controlled programmable flow.
Flow injection methods were first developed by Ruzicka &
Hansen in Denmark in the mid 1970.
Flow injection methods are an outgrowth of segmented flow
procedures which widely used in clinical laboratories for
determination of variety of species in biological fluids for
medical & diagnostic purposes.
3. A typical definition describes FIA as:
· “A simple and versatile analytical technology for
automating wet chemical analysis, based on the physical
and chemical manipulation of a dispersed sample zone
formed from the injection of the sample into a flowing
carrier stream and detection downstream”.
4.
5.
6. FIA techniques fall into four categories:
Flow Injection (FI),
Sequential Injection (SI),
Bead Injection (BI),
Sequential Injection Chromatography (SIC).
7. FI is based in sample injection into a unidirectional flowing carrier
stream to which reagents are added. So, the concentration gradient
is formed by dispersion of the sample zone alone, signal reflects
the gradient of the sample zone, as it passes through the detector.
SI and BI are based on sequential injection of sample and reagents,
into carrier stream, followed by flow reversal that promotes mutual
dispersion of injected zones. The flow of the carrier stream is
programmed, to optimize the assay protocol.
While SI is designed to process liquids, BI uses suspensions of
suitable materials in bead form to assemble columns with solid
reagents or suitable ligands. SIC(sequential injection
chromatography) is emerging chromatographic technique that uses
programmable flow to separate components, based on difference in
migration velocities, on short columns.
8. (1) Conti. mixing methods:- sample is injected in to the system, mixing
it with carrier or reagent, measure the plug flow as it passes
through a suitable detector and either sending to the waste or
recirculating it.
(2) Stopped flow conti. mixing methods:- the flow is stopped at various
stages during the process in order to prevent air from entering the
system between the system aspiration & reagent washing. Flow is
stopped in between these two operations.
(3) Continuous flow titrations:- large dispersion technique, here mixing
chambers are used instead of mixing coils to promote large
dispersion. The sample is mixed with the reagent containing
indicator and then the color is detected.
9. Segmented flow analysis is characterized by the use of one or
several liquid streams where the samples are introduced by
sequential aspiration and are separated by means of air bubbles so,
the final liquid stream is segmented into small discrete liquid by
bubbles of air .
Air-segmented flow analysis (SFA) is a method that automates a
large number of chemical analyses.
SFA was first applied to analysis of sodium and potassium in human
serum, with a flame photometer as the detection device, by
removing protein interferences with a selectively porous membrane
(dialyzer).
10. Principles of Operation.
A sample (analyte) is injected into a carrier solution which
mixes through radial and convection diffusion with a reagent
for a period of time.
Before the sample passes through a detector to waste, a
peristaltic pump is the most commonly used pump in FIA
instruments.
New variants of FIA technique use computer controlled
syringe pumps that generate discontinuous flow .
Decrease of sample and reagent consumption and waste
generation.
11. Inject the liquid sample in to moving conti.
carrier stream of a suitable liquid.
Injected sample forms a zone.
Then zone is transported toward detector conti. & record the
changes in absorbance, electrode potential or other physical
parameter resulting from the passage of the sample material
through the flow cell.
12.
13. First is sampling, where the sample is measured out and injected into the
flowing carrier stream (thus, the name Flow Injection Analysis). This step is
generally performed with a sample injection valve.
Sample processing
Second stage is sample processing. The purpose of this step is to transform
the analyte into a species that can be measured by the detector and manipulate
its concentration into a range that is compatible with the detector, using one or
more of the indicated processes.
Detection
The third stage is detection where the analyte, or a derivative of it, generates a
signal peak that is used to quantify the compound being determined. As
indicated, a large variety of detectors can be used in FIA. The power of FIA as
an analytical tool lies in its ability to combine these analytical functions in a
wide variety of different ways to create a broad range of different
methodologies, and perform these methodologies rapidly and automatically with
minute (μL)amounts of sample. The first and last stages are, largely,
conventional technology.
14.
15. •one involving the simultaneous physical process of
zone dispersion and
•the second involving the chemical process resulting from reaction
between sample and reagent species. A difference in the
concentration gradient is thus generated.
Immediately after injection with a sampling valve, sample zone
(plug) concentration profile is
rectangular shown in figure
A FIA peak occurs due to two processes :
16. As it moves through the tubing, band broadening or dispersion
takes place. The shape of the resulting zone is determined by
two phenomena.
The first is convection arising from laminar flow in which the
centre of the fluid moves more rapidly than the liquid
adjacent to the walls,
thus creating the parabolic shaped front and the skewes zone
profile had shown in figure
Broadening also occurs as a consequence of diffusion.
Two types of diffusion can, in principle, occur:
1. Radial, or Perpendicular to the flow direction
2. Longitudinal or parallel to the flow.
17. The extent of dispersion of dilution is measured in terms
of dispersion coefficient (D). D is the ratio of the
concentration of the sample before and after the
dispersion process takes place.
Dispersion coefficient (D) is defined by the equation
D = C0/C
Where C0 = concentration in injection volume,
C =peak concentration at detector
When a FIA cell is to be fabricated one must know to
what extent the original solution is diluted while
flowing through to the detector and time between the
sample injection point and read out point. Hence
dispersion coefficient (D) is used to decide these
dimensions.
18. D affected by
•· Sample volume
•· Tube length
•· Flow rate
•· Tube id
Three types of sample dispersion
1. Limited dispersion if D=1 to 3,
2. Medium dispersion if D=3 to 10,
3. Large dispersion if D>10
•Out of three limited dispersion is preferred
•Four stages of dispersion process:
injection, dispersion, detection, washout
25. Injection valve,(sample injector)
peristaltic pump,
Coiled reactor,
Tubing manifold
Detector
Auto sampler
Additional components may include a flow through heater to
increase the speed of chemical reactions, columns for sample
reduction, de bubblers, and filters for particulate removal.
Instrumentation of FIA
26.
27.
28.
29.
30.
31. Sample Volume
Increase injection of sample volume increase the peak height until to the steady state
is reached. In single stream system peak height is increase linearly with the injected
sample volume.
The steady state depends on volume geometry & flow rate between injection and flow
cell.
For conventional FIA system this value is around 50µL & for the micro system its as
low as 5µL.
32. Sample Volume & peak Height
•Volume of sample solution injected in to
conventional FI system is
accomplished by manually changing
the volume of sample loop.
•Selection of sensitivity & detection limit
of detector.
•Identification of linear range of detector.
•Automated dilution of sample material.
33. Channel Length
Increasing length of channel
decreases peak height while peak
shape undergoes a change from
symmetrical shape.
At the same time the resident
time of the peak maximum
increases with the distance
travelled and the peak broadens.
This is the principal limitation of
FI based on constant flow rate
limits the incubation time for
chemical reaction to about 20
seconds, with total length of
conduit of 250cm and combined
flow rate around 3mL/min.
34. Residence Time
At continuous flow the
time interval available
for chemical reaction to
take place is defined by
linear flow velocity and
is limited by length of
conduit between point
of injection and
detector.
Stop flow allows longer
reaction time with
penalty of dilution, thus
yielding higher
sensitivity.
It saves reagent and
generates less waste
than continuous
pumping.
All chemical reactions are time dependent.
In this format reaction equilibrium is not necessarily achieved.
36. • The modern Flow Injection Analysis system usually consists
of:
• · An injection valve,
• · A high quality multi channel peristaltic pump,
• · A coiled reactor,
• · A tubing manifold
• · A detector
• · An auto sampler
Additional components may include a flow through heater to
increase the speed of chemical reactions, columns for sample
reduction, de bubblers, and filters for particulate removal.
37. Sample Introduction
Injection valve
Important features of valves suitable for FIA:
· High precision,
· Fast switching,
· Pressure limits of about 100 psi,
· Ability to inject sample volumes from a few micro
litres to several hundred micro litres,
and in some cases fractions of a micro litre.
38. PUMPS
(I) Variable speed peristaltic pump
(ii) Flow rate (0.0005 to 40 ml/min) controlled by pump
speed and tube id
(iii) The pump is used to propel one or more streams
through the Detector via narrow bore (0.5 -0.8 mm ID)
tubing. These streams may be reagents, solvents, or
some other medium such as a buffer. This design leads to
a flow that is relatively pulse free. The flow rate is
controlled by speed of motor, speed is >30 rpm and the
inside diameter of the tubing.
39.
40.
41. DETECTORS
•Detection is most frequently photometric
(UV/VIS and more recently IR).
• In the field of life sciences, different
luminescence techniques are gaining popularity.
•Electrochemical techniques such as
amperometry, and potentiometer, have gained
new life by coupling them to flow-based sample
handling techniques such as FIA.
•Even AAS, ICP-MS and ICP-AES, and even GC
have been coupled to FIA manifolds.
42. Factors Affecting Calibration Standards in FIA
concentration in a sample is usually estimated from the peak
heights, or less frequently peak areas, by using
calibration curves prepared from standards.
If the refractive index of the sample slug is different
from that of the carrier solution, then, because of the parabolic
shape adopted during flow, the slug will act as a lens.
This liquid lens can cause convergence or divergence of the light
from the light source, This effect can
be maximized, and has been used in the determination of re
fractive index (67). For most clinical chemistry analyses this
effect is of little significance, being only a small fraction of the
total absorbance, but for analysis of samples producing a low
absorbance (e.g., <0.05), it may present a problem.
48. Separation in FIA is done by,
1. Dialysis
2. Liquid/liquid extraction,
3. By gaseous diffusion
49. Dialysis is a simple process in which small solutes diffuse from a high
concentration solution to a low concentration solution across a semi
permeable membrane until equilibrium is reached
Since the porous membrane selectively allows smaller solutes to pass
while retaining larger species, dialysis can effectively be used as a
separation process based on size
Dialysis
50. Dialysis cont…
Dialysis is often used continuous-
flow methods to separate inorganic
ions, such as chloride or sodium or
small organic molecules, such as
glucose, from high-molecular-
weight species such as proteins.
51. extraction, is technique used to separate
analytes from interferences in the sample
matrix by partitioning the analytes
between two immiscible liquid.
Extraction
56. It is important that none of the
separation procedures in FIA methods
is ever complete. The lack of
completeness is of no consequence,
however, because unknowns and
standards are treated an identical way.
58. Air-segmented flow analysis (SFA) is a method that
automates a large number of wet chemical analyses. An SFA
analyzer can be thought of as a “conveyor belt” system for
wet chemical analysis, in which reagents are added in a
“production-line” manner.
SFA was first applied to analysis of sodium and potassium in
human serum, with a flame photometer as the detection
device, by removing protein interferences with a selectively
porous membrane (dialyzer).
Segmented Flow Analysis
59. Principle: A rudimentary system (Figure 4120:1)
contains four basic components:
a sampling device,
a liquid transport device such as a peristaltic pump,
the analytical cartridge where the chemistry takes
place
the detector to quantify the analyte.
63. Fig.c: Automated F1Asystem
A sample-withdrawal pump (WP) aspirates the sample from the
sample changer (T) Into the volumetric cavity of a motorized rotary
valve (RV).After a preset time, when the valve cavity has been charged
with sample, the valve is automatically rotated Into the inject position
(horizontal) and the sample is swept through the reaction coil by the
carrier solution (sample and reagent circuits may also be propelled by
a single peristaltic pump).
64. A withdrawal pump (WP) was used to charge a slider valve (SV), shown
in the fig c, with sample. When the valve moves downwards, the
sample is introduced into the carrier stream. PR is a pressurized
reagent reservoir.
Fig. d: Original automated system
65. C is an inert carrier solution into which sample and reagent
are injected.
Fid. E: Synchronous merging zone FIA
71. SFA FIA
Start up time: 20 min
Reagent stream: Gas-
segmented
Reagent consumption:
higher
Manifold: Relatively
complicated to allow
for introduction and
removal of air
Internal dm: 2 mm
20 sec
Non segmented
Slow
Simple
0.5 mm
72. SFA FIA
Sample Introduction:
aspiration
Sample volume: 200 μL
Sampling rate:
Typically 60 (150)
Sample mixing:
Through turbulent flow
generated by gas
bubble and tube wall
friction
Injection
50 μL
150 or greater
through control
dispersion system
73. SFA FIA
Lag phase: significant
Steady state: Usually
required
Readout time: min
Wash cycle : essential
Reproducibility: Better
than 1%
Possibility of long
Incubation times:
suitable
Negligible
Not attained
Sec
Not required
Better than 1%
Not as suitable
74. SFA FIA
Dialysis/solvent
extraction: possible
Titrimetry: Not
possible
Continuous kinetic
analysis: Not possible
Shut down: Slow
(several minutes)
Data acquisition:
Recorded peak height
Possible
Possible
Possible with stopped
flow
Fast (10 s)
Peak height/area or
peak width
75. compared to the manual method,
reduced sample and reagent consumption,
improved repeatability,
minimal operator contact with hazardous materials.
A typical SFA system can analyze 30 to 120 samples/h.
Reproducibility is enhanced by the precise timing and repeatability
of the system. Because of this, the chemical reactions do not need to
go to 100% completion.
The advantages of segmented flow
76. Decreasing the number of manual sample/solution
manipulations reduces labour costs,
improves workplace safety, and improves analytical
precision.
Complex chemistries using dangerous chemicals can be
carried out in sealed systems.
An SFA analyzer uses smaller volumes of reagents and
samples than manual methods,
producing less chemical waste needing disposal
The advantages of segmented flow cont…
78. Determination of Phosphate by FIA
Description of Method:
The FIA determination of phosphate is an adaptation of a
standard spectrophotometric analysis for phosphate. In
the presence of acid, phosphate reacts with molybdate to
form a yellow-coloured complex in which molybdenum is
present as Mo(VI).
H3PO4(aq) + 12H2MoO4(aq) = H3P(Mo12O40)(aq) + 12H2O(l)
In the presence of a reducing agent, such as ascorbic acid,
the yellow-coloured complex is reduced to a blue-
coloured complex of Mo(V).
79. Procedure:
Prepare reagent solutions of 0.005 M ammonium
molybdate in 0.40 M HNO3, and 0.7% w/v ascorbic acid
in 1% v/v glycerine.
Using a stock solution of 100.0-ppm phosphate,
prepare a set of external standards with phosphate
concentrations of 10, 20, 30, 40, 50, and 60 ppm. Use a
manifold similar to that shown in Figure with a 50-cm
mixing coil and a 50-cm reaction coil.
Set the flow rate to 0.5 ml/min. Prepare calibration
curve by injecting 50 mL of each standard, measuring the
absorbance at 650 nm. Samples are analyzed.
Determination of Phosphate by FIA cont...
80. A schematic diagram of the flow manifold is shown in Figure 1.
The injector- commutator (I) is in the injection position.
In this position, the reagent (L1, 250 μL) and the sample or
reference solution (L2, 150 μL) were simultaneously injected and
propelled by carrier streams (5.0 × 10-3 mol L-1 acetate buffer
solution (pH 4.6)), merging at point X. Captopril oxidation by
Fe(III) occurs in reactor coil B1 (50 cm) producing Fe(II) ions that
meet the chromogenic reagent stream (1,10-phenanthroline) at
confluence point Y, with the subsequent chelation of Fe(II) by
1,10-phenanthroline in reactor coil B2 (70 cm).
This product is monitored spectrophotometrically as a stable
tris(1,10-phenanthroline)iron (II) complex at 540 nm.
Determination of captopril by FIA
82. In this work, the development of the reaction occurs in two steps:
the first step is the oxidation of captopril by Fe(III) producing Fe(II)
ions.
In the second step Fe(II) is chelated by 1,10-phenantroline, and the
product is monitored spectrophotometrically as a stable Tris(1,10-
phenanthroline)iron (II) complex at 540 nm (Scheme 1).
Determination of captopril by FIA cont...
84. FI method using spectrophotometric detection at 613 nm is
described for the determination of NZP. The batch method
was adopted as a basis to developed FIA method.
The method is based on oxidative coupling reaction of
reduced NZP with Promethazine hydrochloride in the
presence of sodium periodate to form a green solution.
The FI method has been successfully applied to the
determination of NZP in pharmaceutical tablets.
Determination of NITRAZEPAM by FIA
86. Determination of MELOXICAM by FIA
The methods were based on azo-coupling reaction of meloxicam
with sulphanilic acid in the presence of sodium nitrite in alkaline
medium after converted to primary aromatic amine.