It is an analytical technique useful for the determination of molecular mass, molecular formula and fragmentation pattern of particular molecule and compounds. It has greater application in pharmaceutical and medicinal fields.
This slide discusses the principle, instrumentation, process, detectors, sample ,solvents used in mass spectroscopy and also its applications and limitations.
MASS SPECTROSCOPY ( Molecular ion, Base peak, Isotopic abundance, Metastable ...Sachin Kale
CONTENT:
Molecular Ion Peak
Significance of Molecular ion & Graphically Method
Base Peak
Isotopic Abundance
Metastable Ion
Significance of Metastable ion
Nitrogen Rule & graphs
Formulation of Rule
This slide discusses the principle, instrumentation, process, detectors, sample ,solvents used in mass spectroscopy and also its applications and limitations.
MASS SPECTROSCOPY ( Molecular ion, Base peak, Isotopic abundance, Metastable ...Sachin Kale
CONTENT:
Molecular Ion Peak
Significance of Molecular ion & Graphically Method
Base Peak
Isotopic Abundance
Metastable Ion
Significance of Metastable ion
Nitrogen Rule & graphs
Formulation of Rule
various parts of mAss spectroscopy, applications, principle, peaks, rules, typical mass spectra, various combinations, Fragmentation, rules of fragmentation and useful points which can help Chemical and analytical students and structural elucidation.
Spin-lattice & spin-spin relaxation, signal splitting & signal multiplicity concepts briefly explained relevant to Nuclear Magnetic Resonance Spectroscopy.
GAS CHROMATOGRAPHY-MASS SPECTROSCOPY [GC-MS]Shikha Popali
THIS PRESENTATION GIVES A DETAIL ACCOUNT ON THE GC-MS WITH ITS INTRODUCTION, BASIC PRINCIPLE OF BOTH COMBINED AND INDIVIDUALLY WITH ITS INSTRUMENTATION, APPLICATION AND EXAMPLES, MAKES EASY TO COLLECT ALL THE DATA AT A PLACE ACCORDING TO THE M.PHARM SYLLABUS S PER PCI
Nuclear magnetic resonance (NMR) spectroscopyVK VIKRAM VARMA
SPECTROSCOPY
NMR SPECTROSCOPY
HISTORY
THEORY
PRINCIPLE
INSTRUMENTATION
SOLVENTS USED IN NMR(PROTON NMR)
CHEMICAL SHIFT
FACTORS AFFECTING CHEMICAL SHIFT
RELAXATION PROCESS
SPIN-SPIN COUPLING
푛+1 RULE
NMR SIGNALS IN VARIOUS COMPOUNDS
COUPLING CONSTANT
NUCLEAR MAGNETIC DOUBLE RESONANCE/ SPIN DECOUPLING
FT-NMR
ADVANTAGES & DISADVANTAGES
APPLICATIONS
REFERENCE
Mass spectrometry principle working inttumentation advantages diadvantages GC...sneha010196
Mass spectroscopy
History
What is mass number
Ms principle
Ms working
Instrumentation
Mass analysers
Fragmentation rules
Nitrogen rule
Types of peaks
Interpretation of spectra
Gc ms
Applications of ms
Advantages & disadvantages
Reference.
various parts of mAss spectroscopy, applications, principle, peaks, rules, typical mass spectra, various combinations, Fragmentation, rules of fragmentation and useful points which can help Chemical and analytical students and structural elucidation.
Spin-lattice & spin-spin relaxation, signal splitting & signal multiplicity concepts briefly explained relevant to Nuclear Magnetic Resonance Spectroscopy.
GAS CHROMATOGRAPHY-MASS SPECTROSCOPY [GC-MS]Shikha Popali
THIS PRESENTATION GIVES A DETAIL ACCOUNT ON THE GC-MS WITH ITS INTRODUCTION, BASIC PRINCIPLE OF BOTH COMBINED AND INDIVIDUALLY WITH ITS INSTRUMENTATION, APPLICATION AND EXAMPLES, MAKES EASY TO COLLECT ALL THE DATA AT A PLACE ACCORDING TO THE M.PHARM SYLLABUS S PER PCI
Nuclear magnetic resonance (NMR) spectroscopyVK VIKRAM VARMA
SPECTROSCOPY
NMR SPECTROSCOPY
HISTORY
THEORY
PRINCIPLE
INSTRUMENTATION
SOLVENTS USED IN NMR(PROTON NMR)
CHEMICAL SHIFT
FACTORS AFFECTING CHEMICAL SHIFT
RELAXATION PROCESS
SPIN-SPIN COUPLING
푛+1 RULE
NMR SIGNALS IN VARIOUS COMPOUNDS
COUPLING CONSTANT
NUCLEAR MAGNETIC DOUBLE RESONANCE/ SPIN DECOUPLING
FT-NMR
ADVANTAGES & DISADVANTAGES
APPLICATIONS
REFERENCE
Mass spectrometry principle working inttumentation advantages diadvantages GC...sneha010196
Mass spectroscopy
History
What is mass number
Ms principle
Ms working
Instrumentation
Mass analysers
Fragmentation rules
Nitrogen rule
Types of peaks
Interpretation of spectra
Gc ms
Applications of ms
Advantages & disadvantages
Reference.
INTRODUCTION of Mass Spectrometry, Applications of Mass Spectrometry,Principle of Mass Spectrometry, Mass Spectrum,MOLECULAR ION PEAK, MOLECULAR ION / PARENT PEAK, BASE PEAK, Metastable ion ,Instrumentation of Mass Spectrometry, Electron impact spectra, CHEMICAL IONIZATION, ELECTROSPRAY IONISATION, MATRIX ASSISTED DESORPTION / IONISATION(MALDI), FAST ATOM BOMBARDMENT SOURCE,Ion separator (analyzer), Types of mass spectrometers, Single focussing spectrometers,Time of flight systems,FRAGMENTATION of Mass Spectrometry.
Uploaded By: Mr. Shubham sutradhar (masters in
pharmaceutical Chemistry).
Mass spectroscopy & it's instrumentations, Ionization Techniques, Mass Spectroscopic Analyzers & it's applications. above topics are discussed in a brief format.
Introduction, Basic Principles, Terminology, Instrumentation, Ionization techniques (EI, CI, FAB, MALDI, and ESI), Mass Analyzer (Magnetic sector instruments, Quadrupole, TOF, and ICR ), and Applications of Mass Spectrometry.
Mass spectrometry (MS) is an analytical technique that is used to measure the molecular weight of the compounds. The results are typically presented as a mass spectrum, a plot of intensity as a function of the mass-to-charge ratio.
Country wise comparison of essential drugs on the basis of rational drug use ...AJAYKUMAR4872
The provision of Essential medicine is one of the eight pillars of WHO’s primary health care strategy. According to WHO, essential medicines are those drugs that fulfill the priority health care need of people. Essential drug is defined as the appropriate medicine intended to be available in the content of functioning health system every time in adequate amount in the appropriate dosage form with assured quality and adequate information at affordable price that each and every individual can afford.
Iron deficiency anemia is the most advanced stage of iron deficiency which is characterized not only by low hemoglobin and Hematocrit levels but also by a reduction or depletion of iron stores, by low serum iron levels and decreased transferrin saturation.
UV spectroscopy is an analytical method used to detct the numbers of double and triple bonds present in dienes ,trienes and polyenes compounds.The energy corresponds to EM radiation in the ultraviolet (UV) region, 100-350 nm, and visible (VIS) regions 350-700 nm of the spectrum is known as UV spectrum.
Quality is absolute and universally recognizable. It is often loosely related to a comparison of features and characteristics of products, as ANSI/ASQ defines as relative quality.For Example, high-priced German automobiles are often thought of as being of higher quality than the lower priced models of other manufacturers.A management approach for an organization, centered on quality, based on the participation of all its members and aiming at long-term success through customer satisfaction, and benefits to all members of the organization and to society which can be called as Total Quality Management(TQM).
Q.R are planned and documented by an inspections of a review item
The review item may be a product, a group of related products or a part of a product
If the error identified earlier the cost of implication is less and the penalty for failing to conduct adequate reviews.
Documentation control - principles of GMPAJAYKUMAR4872
Documentation is an essential part of QA and relates to all aspects of GMP.
The pharmaceutical industry must have a good document framework (infrastructure).
It is important for a manufacturer to get the documentation right in order to get the product right.
Analytical Method Validation is a process that is used to demonstrate the suitability of an analytical method for an intended purpose.Regulations and quality standards that have an impact on analytical laboratories require analytical methods to be validated.
ISO:9000 family means organization of a product or service assuring continued quality assurance to customer delight.ISO 9000 was created to produce an international set of process quality standards.It consists of Written procedures that were inspected to ensure consistency
Electromagnetic radiation consists of waves of the electromagnetic field, propagating through space, carrying electromagnetic radiant energy. It includes radio waves, microwaves, infrared, light, ultraviolet, X-rays, and gamma rays. All of these waves form part of the electromagnetic spectrum.EMR is released when excited atoms or molecules return to ground state and this process is called emisssion.
EMR has both electric (E) and magnetic (H) components that propagate at right angles to each other.
It is the documented act of proving that any procedure, process, equipment, material, activity or system actually leads to the expected result.
It is the confirmation by examination and the provision of objective evidence that the particular requirements for a specific intended use are fulfilled.
It is an analytical technique uselful for detection of functional groups present in particular molecules and compounds.
It is highly applicable in pharmaceutical and chemical engineering.
It is spectroscopy technique to determine number of hydrogen atoms present in the molecules and atoms.It is useful method for separation of molecules and compounds from mixtures components highly recommended in pharmaceutical and chemical engineering fields.
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/
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.
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.
Multi-source connectivity as the driver of solar wind variability in the heli...Sérgio Sacani
The ambient solar wind that flls the heliosphere originates from multiple
sources in the solar corona and is highly structured. It is often described
as high-speed, relatively homogeneous, plasma streams from coronal
holes and slow-speed, highly variable, streams whose source regions are
under debate. A key goal of ESA/NASA’s Solar Orbiter mission is to identify
solar wind sources and understand what drives the complexity seen in the
heliosphere. By combining magnetic feld modelling and spectroscopic
techniques with high-resolution observations and measurements, we show
that the solar wind variability detected in situ by Solar Orbiter in March
2022 is driven by spatio-temporal changes in the magnetic connectivity to
multiple sources in the solar atmosphere. The magnetic feld footpoints
connected to the spacecraft moved from the boundaries of a coronal hole
to one active region (12961) and then across to another region (12957). This
is refected in the in situ measurements, which show the transition from fast
to highly Alfvénic then to slow solar wind that is disrupted by the arrival of
a coronal mass ejection. Our results describe solar wind variability at 0.5 au
but are applicable to near-Earth observatories.
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.
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.
2. History of Mass Spectrometry
2
Year Scientist Discovery/Award
1886 E. Goldstein Discovers anode rays (positive gas ions) in
gas discharge
1897 J.J.Thomson Discovers the electron and determines its
m/z ratio. Nobel Prize in 1906
1898 W.Wien Analyzes the anode rays by magnetic
deflection, and establishes that they carry a
positive charge.
Nobel Prize in 1911
1909 R.A. Millikan &
H. Fletcher
Determine the elementary unit of charge
3. Mass Spectrometry
3
Year Scientist Discovery/Award
1912 J.J.Thomson First Mass Spectrometer. In 1913 J. J.Thomson
separated the isotopes 20Ne and 22Ne
1919 A.J. Dempster Electron ionization and magnetic sector MS
1942 Atlantic
Refining
Company
First commercial use
This technique resolves ionic species by their m/e
ratio
1953 W. Paul and
H.S.
Steinwedel
Quadrupole and the ion trap.
Nobel Prize to Paul in 1989.
4. Mass Spectrometry
4
Year Scientist Discovery/Award
1956 First GC-MS
1968 First commercial quadrupole
1975 First commercial GC-MS
1990s Explosive growth in biological MS, due to ESI
& MALDI
2002 Fenn &
Tanaka
Nobel Prize to Fenn &Tanaka for ESI & MALDI
2005 Commercialization of Orbitrap MS
5. Mass Spec - Introduction
Very different from IR and NMR
Absorption of electromagnetic energy
Sample can be recovered and reused
Mass spectrometry
Records what happens when an organic molecule is hit
by a beam of high-energy electrons
Sample is completely destroyed
6. Mass Spec - Introduction
What does a mass spectrum tell us?
1. Molecular weight
2. Molecular formula
Either directly or in conjunction with other kinds
of spectra such as IR or NMR
3. Fragmentation pattern
Key pieces of what the molecule looks like (such
as methyl, ethyl, phenyl, or benzyl groups
7. Ms spectrometry gives composition of sample.
Structure of inorganic, organic & biological sample
Qualitative & quantitative composition of solid surfaces
Isotopic ratios of atoms in samples
Atomic or Molecular weight expressed in terms of
atomic mass unit (amu) or daltons (Da).
Introduction to Mass Spectrometry
8. The amu is based upon the relative scale in which the
reference is carbon isotope C-12.
Thus amu is defined as 1/12 the mass of the one neutral
C-12
Molecular weight can be obtained from a very small sample.
It does not involve the absorption or emission of light.
A beam of high-energy electrons breaks the molecule apart.
The masses of the fragments and their relative abundance
reveal information about the structure of the molecule.
8
9. Separation of Ions
Only the cations are deflected by the magnetic field.
Amount of deflection depends on m/z.
The detector signal is proportional to the number of ions
hitting it.
By varying the magnetic field, ions of all masses are
collected and counted.
9
10. Atomic MS Acronym Atomic ion
source
Typical Ms
analyzer
Inductive coupled
plasma
ICPMS High temp. argon
plasma
Quadruple
Direct current
plasma
DCPMS High temp. argon
plasma
Quadruple
Microwave
induced plasma
MIPMS High temp. argon
plasma
Quadruple
Spark source SSMS Radio frequency
electric spark
Double focusing
Thermal
ionization
TIMS Electrically
heated plasma
Double focusing
Glow discharge GDMS Glow discharge
plasma
Double focusing
Laser microprobe LMMS Focused laser
beam
Time of flight
Secondary ion SIMS Accelerated ion
bombardment
Double focusing
11. - Used quantitatively and qualitatively
(identification)
Useful for both organic and inorganic compounds
Can measure ~ 75 elements
Rapidly evolving technology
Expensive and complex
11
General Characteristics and Features
12. 12
A B + e
molecular ion =
cation-radical
(high energy)
electron beam;
~5000 kJ/mol
fragmentation
cations + neutral species (radicals)
: A B+
+ 2 e
Mass Spectrometry…
Sample is ionized (an electron is removed) M
.+
Ionization frequently fragments molecules
bonds most likely to break are the weakest -> form cations & radicals
Modern techniques can be used to study non-volatile
molecules such as proteins and nucleotides
13. MS perform three functions:
Creation of ions – the sample molecules are subjected
to a high energy beam of electrons (70 eV), converting
some of them to ions
Separation of ions – as they are accelerated in an
electric field, the ions are separated according to mass-
to-charge ratio (m/z)
Detection of ions – as each separated population of
ions is generated, the spectrometer needs to qualify
and quantify them
All type of MS need very high vacuum (~ 10-6 torr),
16. Components of MS
1. Sample Introduction System
Volatilizes the sample and introduces it to the
ionization chamber under high vacuum
2. Ion Source
Ionizes the sample (fragmentation may occur) and
accelerates the particles into the mass analyzer
3. Mass Analyzer (or Mass Separator)
Separates ionized particles based on their mass-to-
charge ratio (m/e-)
16
17. Components of MS
4. Detector - Ion Collector
Monitors the number of ions reaching detector per
unit time as a current flow
5. Signal Processor
Amplifies the current signal and converts it to a DC
Voltage
6. Vacuum Pump System
A very high vacuum (10-4 to 10-7 torr) is required so
that the generated ions are not deflected by
collisions with internal gases
17
18. Mass Spectrometry
II. The Mass Spectrometer
B. Single Focusing Mass Spectrometer
A small quantity of sample is injected and vaporized under
high vacuum
The sample is then bombarded with electrons having 70-80
eV of energy
A valence electron is “punched” off of the molecule, and an
ion is formed
19. Mass Spectrometry
II. The Mass Spectrometer
B. The Single Focusing Mass Spectrometer
4. Ions (+) are accelerated using a (-) anode towards the focusing magnet
5. At a given potential (1 – 10 kV) each ion will have a kinetic energy:
½ mv2 = eV
As the ions enter a magnetic field, their path is curved; the radius of the
curvature is given by:
r = mv
eH
If the two equations are combined to factor out velocity:
m/e = H2r2
2V
m = mass of ion
v = velocity
V = potential difference
e = charge on ion
H = strength of magnetic field
r = radius of ion path
20. Mass Spectrometry
II. The Mass Spectrometer
B. Single Focusing Mass Spectrometer
6. At a given potential, only one mass would have the correct
radius path to pass through the magnet towards the detector
7. “Incorrect” mass particles would strike the magnet
21. Ion Sources
Purpose: create gaseous ions out of the sample
components
Two types:
1. Molecular sources
gas phase
desorption sources
2. Elemental sources
21
22. Ion Sources MS (cont.)
Type S.No Name and Acronym Ionizing Process
Gas Phase 1 Electron Impact (EI) Exposure to electron
stream
2 Chemical Ionization (CI) Reagent gaseous
ions
3 Field Ionization (FI) High potential
electrode
Desorption 1 Field Desorption (FD) High potential
electrode
2 Electrospray Ionization (ESI) High electric field
3 Matrix-assisted desorption
ionization (MALDI)
Laser beam
4 Plasma Desorption (PD) Fission fragments
from 252Cf
5 Fast Atom Bombardment (FAB) Energetic atomic
beam
6 Secondary Ion Mass
Spectrometry (SIMS)
Energetic beam of
ions
7 Thermospray Ionization (TS) High temperature22
23. Electron Impact Ionization
Ionization methods required for gaseous sample.This method is
not useful for non volatile or thermally unstable molecule.
In desorption technique sample directly converted in to gaseous
ions.
We hit an organic molecule with a beam of electrons (usually 70-75
eV)
M + e– M+ + e– + e– ionization
M+ A+ + B fragmentation
That removes an electron from the molecule resulting in the
molecular ion (a radical cation)
The molecular ion then fragments in smaller radicals and cations
The cations are detected by the MS instrumentation
25. Chemical Ionization
25
Gaseous sample
atoms are ionized by
collision with
positively charged
“reagent” gases (e.g.
CH4
+).
The reagent ions are
produced by electron
bombardment
A0 (g) + CH4
+ (g) -------> A+ (g) + CH4
0 (g)
26. Chemical Ionization (CI)
A modified form of EI
Higher gas pressure in ioniation cavity (1 torr)
Reagent gas (1000 to 10000-fold excess) added; usual
choice is methane, CH4
•
•A “soft ionization” technique
• Reagent gases are ionized
o methanol, methane, ammonia, others
• Sample molecules collide with the ionized reagent gas
o usually results in a proton transfer from the reagent gas to
the sample compound
o so M+1 ions are common
29. Field Ionization and
Desorption
Intense electric field
(107-108 V/cm)
Electrons “tunnel”
into pointed electrode,
yielding positive ions
with little excess energy
Very gentle; little fragmentation
In Field Desorption, anode coated with analyte
Not as efficient as EI sources by an order of
magnitude
Waller 1972, Mc Fadden 1973, Beckey 1969
29
30. Electrospray Ionization
Source
30
How it Works
Small, electrically charged
droplets are formed from a
solution flowing out of a
hollow needle into a chamber
under low vacuum
The charged droplets are
attracted to an electrode
across an open volume by
the application of an
electrical field in the open
chamber
31. Electrospray Ionization Source
Some of the solvent is evaporated (and concentration occurs)
during transit across the chamber
As the droplets shrink, ions are forced closer together. At
some point the repulsive forces between the ions is greater
than surface tension and small droplets break off the larger
drops.
This process continues several times as the droplets transit
across the chamber
Eventually the solvent disappears and ions are generated, a
process called ion evaporation& analysed by quadrupole Mass
analyser
31
32. Matrix-Assisted Laser
Desorption/Ionization (MALDI)
Analyte mixed with radiation-absorbing material such as
Nicotinic acid, Benzoic acid deriv., Pyrazine –carboxylic acid,
cinnamic acid deriv., Nitrobenzyl alcohol
The resulting solution was evaporated on the metallic probe
surface and dried
Sample mixture was exposed to pulsed laser beam, which
result in the sublimation of analyte ion and were drawn into
time-of-flight (TOF) analyser for analysis
Excellent for larger molecules, e.g. peptides, polymers
32
33. Inductively Coupled Plasma (ion
source)
Plasma
An electrically conducting gaseous
mixture containing cations and anions
∑ cation(s) charge = ∑ electron charge
Argon Plasma
Ar is the principal conducting species
Temperatures of 10,000 K possible
Powered by radiofrequency energy (2
kW @ 27 Mhz)
33
34. Inductively Coupled Plasma (ion
source)
An ICP “torch” consists of:
Three concentric quartz tubes
through which a stream of argon
flows at a rate of 5-20 L/min
The three concentric rings are
constructed to eliminate
atmospheric gases from contacting
the sample stream in the inner-
most ring
34
35. Inductively Coupled Plasma (ion
source)
An argon plasma is
generated by a water-
cooled induction coil
through which a radio-
frequency energy (0.5 to 2
kW of power at 27-41 MHz)
is transmitted
Ionization of the flowing
argon must be “initiated”
by aTesla coil
35
Radiofrequency
Induction Coil
Argon Plasma
36. Inductively Coupled Plasma (ion
source)
Sample is introduced through
the inner-most ring in the torch
as a “mist” carried by the argon
stream
The “mist” is generated by a
nebulizer
36
Sample Inlet Tube
Cetac Ultrasonic Nebulizer
37. Inductively Coupled Plasma (ion
source)
Analytes are ionized in the argon
plasma and the ionized gas (i.e.
plasma) is positioned on the
entrance to the mass spectrometer.
The interface consists of a series of
metal (Pt, or Ni) cones with a small
hole permitting the ions to be
drawn in by the large vacuum on
the inside.
Can measure 90% of the elements
in the periodic table can be
simultaneously measured
37
MS Interface
38. Fast Atom Bombardment
Ion source for
biological molecules
Ar ions passed
through low pressure
Ar or Xe gas to produce
beam of neutral ions
Atom-sample collisions
produce ions as large as 25,000 Daltons
38
39. Fast Atom Bombardment Ionization
Source
39
Ar+* + Ar0 ----------------> Ar+ + Ar0*
Production of “fast atoms”
Charge transfer
Accelerated
argon ion
from “ion
gun”
Ground
state
argon
atom
“slow ion” “fast atom”
(a) The atom gun
(b) The atom beam
(c) Metal sample holder
(d) The end of the probe arm used to insert the
sample into the chamber
(e) The sample in the low volatility solvent
(f) The sample ion driven from the surface
(g) Ion extraction plate-select positive ions for
mass analysis
(h) Ion lens system leading to mass analyser
40. FAB Characteristics
Used with high molecular weight organic molecules
The fast atom interacts with analyte on a “target” to produce
ions by “sputtering” (i.e. transfer of energy from argon to
analyte)
Analyte ions are accelerated into the MS by application of an
electric field (ion extraction plate and lenses)
40
41. Thermal Ionization (Ion) Source
41
How it Works
It employ two wire filaments (usually
tungsten or rhenium) closely spaced
(~ 1 mm) situated in a chamber under
high vacuum
The sample is coated (usually in a
silica gel matrix with phosphoric acid
coated on top) on one wire filament
that is heated gently
The second filament, the ionizing
filament is heated to incandescence
The analyte desorbs from the
filament and become ionized by the
second filament.
Sample ions are accelerated into the
MS by application of an electric field
Characteristics
Old ionization method (70+
years)
Used primarily for very high
precision isotopic ratio studies
of the elements
42. Example Resolution Calculation
1. What is the resolution required to separate
particles having masses of 999 and 1001?
500
2
1001)/2
(999
R
42
(1 part in 500)
2. For Masses of 28.0061 (N2
+) and 27.9949
(CO+)
2500
0.00112
28.0005
27.9949)
-
(28.0061
27.9949)/2
(28.0061
R
(1 part in 2500)
44. Sample Introduction -Direct MS
Inlet
Four BasicTypes:
1. Batch Inlet
Sample is volatilized externally
and allowed to “leak” into the
ion source
Good for gas and liquid
samples with boiling points <
500 °C
Major interface problem –
carrier gas dilution
44
Purpose: Introduce the sample (as a gas) into the
ion source under high vacuum- GC MS
45. Direct Probe
Good for non-volatile liquids, thermally unstable
compounds and solids
Sample is held on a glass capillary tube, fine wire or
small cup
45
A mixture of compounds is separated by gas chromatography,
then identified by mass spectrometry (GC-MS Inlets)
48. Thermospray- Inductively Coupled
Plasma (ICP)
Operates somewhat like a
nebulizer in an AAS
Also ionizes the sample in
argon stream (at very high
temperatures, >6000 °C)
Only a small amount of
analyte is utilized (< 1%)
48
49. Mass Analyzer
The function of the MS analyzer like monochromator in
an optical spectrometer.
Transducer converts the beam of ions to an electrical
signal that can be then Processed, stored in memory.
MS require an elaborate vacuum system to maintain a
low pressure in all of the components except signal
processor
50. Mass Analyzers
Type Mass Range Resolution Sensitivity Advantage Disadvantage
Magnetic
Sector
1-15,000
m/z
0.0001 Low High
resolution
Expensive
Quadrupole 1-5000 m/z Unit High Easy to use;
inexpensive
Low res; low
mass
Ion trap 1-5000 m/z Unit High Easy to use;
inexpensive
Low res; low
mass
Time of
Flight
Unlimited 0.0001 High High mass;
simple design
Fourier
Transform
Up to 70
kDa
0.0001 High Very high res
and mass
Very expensive
Silverstein, et. al., Spectrometric Identification of Organic Compounds, 7th Ed, p 13.
Single Focus
Double Focus
51. Mass Analyzers
There are several methods for separating different
masses
Elemental analysis -Want to distinguish between
individual mass units
particles)
two
(of
mass
in
difference
particles)
two
(of
mass
average
Resolution
51
54. Single Focusing Magnetic Sector
Mass Analyzer
54
Masses are
separated in a
(single) magnetic
field
Ions are deflected
60-180°
Varying the
magnetic field
separates the
masses
55. Double Focus
Ion source produces ions
with a certain spread of
Kinetic Energy (K.E.).
Electrostatic field and exit
slit select only ions with
same K.E.
Net effect is to increase R to
2500-150000
Can distinguish very similar
ions, e.g., C2H4
+ (28.0313)
and CO+ (27.9949)
55
56. Double Focusing Magnetic Sector
Mass Analyzer
56
A “double focusing” analyzer
has two regions of mass
separation
Magnetic Field preceded
by an electrostatic field
The electrostatic field
helps to isolate particles of
a specific kinetic energy
Ion sources which produce
particles of variable kinetic
energy have low resolution
57. Quadrupole Mass Analyzers
57
Mass separation is achieved using 4
electrically connected rods (two “+”
and two “-”)
Both DC and AC signals are passed
through the rods to achieve
separation
Scans are achieved by varying the
frequency of the (AC) radio-
frequency or by varying potentials of
the two sources while keeping their
ratio and frequency constant
59. Quadrupole Analyzer
Ions forced to wiggle
between four rods whose
polarity is rapidly
switched
Small masses pass
through at high
frequency or low voltage;
large masses at low
frequency or high voltage
Very compact, rapid (10
ms)
R = 700-800
59
60. Merit and Demerit
Classical mass spectra
Good reproducibility
Relatively small/ compact,
Relatively low-cost systems
Limited resolution
Peak heights variable as a function of mass (mass
discrimination). Peak height vs. mass response must be
'tuned'.
Not well suited for pulsed ionization methods
60
61. Quadrupole Ion Trap
Ions follow complex
trajectories between two
pairs of electrodes that
switch polarity rapidly
Ions can be ejected from
trap by m/z value by
varying the frequency of
end cap electrodes
61
62. Time of Flight Mass Analyzer
62
Operation Characteristics
Separates ions based on flight time in drift tube
Positive ions are produced in pulses and accelerated in an
electric field (at the same frequency)
All particles have the same kinetic energy but the velacities
vary with mass of the ions
Lighter ions reach the detector first
Typical flight times are 1-30 µsec
64. Time of Flight Mass Analyzer
Separation Principle
All particles have the same kinetic energy
In terms of mass separation principles:
Vparticle = Her/m
Hold H,e, and r constant
Vparticle = 1/m (constant)
Vparticle is inversely proportional to mass
64
66. Detectors for MS
Two BasicTypes
1. Electron Multipliers
2. Faraday Cup
Time of Flight (TOF) and FourierTransform Ion-
Cyclotron Resonance (FTICR) instruments can
separate more than one m/e- ratio
simultaneously
Multiple detectors are required in this case
66
67. Discrete Dynode Electron
Multiplier
Operates somewhat like a
PMT tube
Each dynode is at successively
higher potential
Produces a cascade of electrons
67
68. Channel (or Continuous) Dynode
Electron Multiplier
A glass tube that is coated
with lead or a conductive
material
A potential of ~ 2000V is
applied between the
opening and the end of the
tube
The curved shape helps to
reduce electrical noise by
preventing positive ions
returning upstream.
68
69. Dynode-Based Detectors
A disadvantage of dynode-based detectors is
that the number of secondary electrons released
in a detector depends on the type of primary
particle, its energy and its incident angle,
Mass discrimination occurs when ions enter the
detector with different velocities.
69
71. Faraday Cup
71
How it Works
Ions exiting the analyzer strike the
collector electrode
The faraday cage prevents escape
of reflected ions and ejected
secondary electrons
The inclined collector reflects ions
away from the entrance
The collector is connected to
ground via a large resistor
Positive ions are neutralized on the
surface of the collector by a flow of
electrons (from ground) through
the resistor
The potential energy difference
across the resistor is amplified
72. Faraday Cup
Characteristics
Inexpensive
Low sensitivity
Slow response
A metal or carbon cup
Produces a few micro amps of current (that is
then amplified)
Current is directly proportional to number of
ions entering
Detector response is independent of ion
Kinetic energy
Mass
Chemical nature
Does not exhibit mass discrimination
Used in isotope ratio MS
72
73. Application of MS
1. Drug discovery, combinatorial chemistry, Drug
testing/Pharmacokinetics
2. Antiterror/Security (e.g. bomb molecule ‘sniffers’)
3. Environmental Analysis (e.g. water quality testing)
4. Quality Control (food, pharmaceuticals)
5. Medical Testing (various blood illnesses and… cancer?)
6. Validation of art/History/Anthropology etc.
7. Validation during chemical synthesis
8. Biochemical research (proteomics, interact…omics)
9. Tissue imaging (with MALDI)
10. Analysis of Proteins, peptides, olegonucleotides
11. Clinical testing etc 73
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