The document provides information about mass spectrometry including:
- Mass spectrometry is a powerful analytical technique that uses instruments called mass spectrometers to identify molecules by breaking them into ionized fragments and measuring their mass-to-charge ratios.
- The basic components of a mass spectrometer are the sample inlet, ionization source, mass analyzer, and ion detector. Common ionization sources are electrospray ionization, matrix-assisted laser desorption/ionization, and electron ionization. Common mass analyzers are quadrupoles, ion traps, and time-of-flight.
- Mass spectrometry has a variety of applications and has undergone significant technological developments since its invention in the early 20th
a type of an analyzer used in mass spectrometer. separates the ions based on mass to charge ratios. useful for the detection of ions present in the sample
introduction and principle of Mass spectrometry with its components.
ionization , accelerators deflection and detection, types of MS, different types of ion sources , types of mass analyzers , advantages and disadvantages of different types of ion source and mass analyzers, different types of detectors for the ions dectections
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.
IR SPECTROSCOPY, INTRODUCTION, PRINCIPLE, THEORY, FATE OF ABSORBED RADIATION, FERMI RESONANCE, FINGERPRINT REGION, VIBRATIONS, FACTORS AFFECTING ABSORPTION OF IR RADIATION, SAMPLING TECHNIQUES, APPLICATIONS OF IR SPECTROSCOPY.
In this slide contains Interference In Atomic Absorption Spectroscopy and applications.
Presented by: Shaik Gouse ul azam. ( department of pharmaceutical analysis.)
RIPER, anantpur.
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
Quadrupole and Time of Flight Mass analysers.Gagangowda58
Description about important mass analysers Quadrupole and TOF: Principle, Construction and Working, Advantages and Disadvantages and their Applications.
a type of an analyzer used in mass spectrometer. separates the ions based on mass to charge ratios. useful for the detection of ions present in the sample
introduction and principle of Mass spectrometry with its components.
ionization , accelerators deflection and detection, types of MS, different types of ion sources , types of mass analyzers , advantages and disadvantages of different types of ion source and mass analyzers, different types of detectors for the ions dectections
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.
IR SPECTROSCOPY, INTRODUCTION, PRINCIPLE, THEORY, FATE OF ABSORBED RADIATION, FERMI RESONANCE, FINGERPRINT REGION, VIBRATIONS, FACTORS AFFECTING ABSORPTION OF IR RADIATION, SAMPLING TECHNIQUES, APPLICATIONS OF IR SPECTROSCOPY.
In this slide contains Interference In Atomic Absorption Spectroscopy and applications.
Presented by: Shaik Gouse ul azam. ( department of pharmaceutical analysis.)
RIPER, anantpur.
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
Quadrupole and Time of Flight Mass analysers.Gagangowda58
Description about important mass analysers Quadrupole and TOF: Principle, Construction and Working, Advantages and Disadvantages and their Applications.
MASS SPECTROMETRY(mass-spec) -2013 - P.ravisankar- WHAT ABOUT MASS SPECTROMET...Dr. Ravi Sankar
MASS SPECTROMETRY(mass-spec) -2013 - P.ravisankar-WHAT ABOUT MASS SPECTROMETRY,BASIC PRINCIPLE,INSTRUMENTATION, ION SOURCES, MASS ANALYZERS,APPLICATIONS.
P.RAVISANKAR, VIGNAN PHARMACY COLLEGE, VADLAMUDI
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- 3rd lecture
Ionization methods
Electron Impact (EI),
Chemical Ionization (CI),
Field Desorption (FD),
Fast Atom Bombardment (FAB),
Plasma Desorption (PD),
Matrix assisted laser desorption (MALDI),
Thermospray Mass and
Electrospray(ESI)
Analysis techniques
Magnetic Sector
Quadrupole
Ion Trap
Time-of-Flight (TOF)
Fourier Transform (FT)
This presentation contains a simple discussion about the basic principles, Instrumentation, Various ionization techniques, mass analyzers, Mass detectors, Fragmentation, and various peak observed in Mass spectra(Molecular ion peak, Metastable peak, Base peak etc)
And application of Mass spectroscopy on various field.
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An EFL lesson about the current events in Palestine. It is intended to be for intermediate students who wish to increase their listening skills through a short lesson in power point.
Instructions for Submissions thorugh G- Classroom.pptxJheel Barad
This presentation provides a briefing on how to upload submissions and documents in Google Classroom. It was prepared as part of an orientation for new Sainik School in-service teacher trainees. As a training officer, my goal is to ensure that you are comfortable and proficient with this essential tool for managing assignments and fostering student engagement.
Embracing GenAI - A Strategic ImperativePeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
Unit 8 - Information and Communication Technology (Paper I).pdfThiyagu K
This slides describes the basic concepts of ICT, basics of Email, Emerging Technology and Digital Initiatives in Education. This presentations aligns with the UGC Paper I syllabus.
A Strategic Approach: GenAI in EducationPeter Windle
Artificial Intelligence (AI) technologies such as Generative AI, Image Generators and Large Language Models have had a dramatic impact on teaching, learning and assessment over the past 18 months. The most immediate threat AI posed was to Academic Integrity with Higher Education Institutes (HEIs) focusing their efforts on combating the use of GenAI in assessment. Guidelines were developed for staff and students, policies put in place too. Innovative educators have forged paths in the use of Generative AI for teaching, learning and assessments leading to pockets of transformation springing up across HEIs, often with little or no top-down guidance, support or direction.
This Gasta posits a strategic approach to integrating AI into HEIs to prepare staff, students and the curriculum for an evolving world and workplace. We will highlight the advantages of working with these technologies beyond the realm of teaching, learning and assessment by considering prompt engineering skills, industry impact, curriculum changes, and the need for staff upskilling. In contrast, not engaging strategically with Generative AI poses risks, including falling behind peers, missed opportunities and failing to ensure our graduates remain employable. The rapid evolution of AI technologies necessitates a proactive and strategic approach if we are to remain relevant.
How to Make a Field invisible in Odoo 17Celine George
It is possible to hide or invisible some fields in odoo. Commonly using “invisible” attribute in the field definition to invisible the fields. This slide will show how to make a field invisible in odoo 17.
2024.06.01 Introducing a competency framework for languag learning materials ...Sandy Millin
http://sandymillin.wordpress.com/iateflwebinar2024
Published classroom materials form the basis of syllabuses, drive teacher professional development, and have a potentially huge influence on learners, teachers and education systems. All teachers also create their own materials, whether a few sentences on a blackboard, a highly-structured fully-realised online course, or anything in between. Despite this, the knowledge and skills needed to create effective language learning materials are rarely part of teacher training, and are mostly learnt by trial and error.
Knowledge and skills frameworks, generally called competency frameworks, for ELT teachers, trainers and managers have existed for a few years now. However, until I created one for my MA dissertation, there wasn’t one drawing together what we need to know and do to be able to effectively produce language learning materials.
This webinar will introduce you to my framework, highlighting the key competencies I identified from my research. It will also show how anybody involved in language teaching (any language, not just English!), teacher training, managing schools or developing language learning materials can benefit from using the framework.
June 3, 2024 Anti-Semitism Letter Sent to MIT President Kornbluth and MIT Cor...Levi Shapiro
Letter from the Congress of the United States regarding Anti-Semitism sent June 3rd to MIT President Sally Kornbluth, MIT Corp Chair, Mark Gorenberg
Dear Dr. Kornbluth and Mr. Gorenberg,
The US House of Representatives is deeply concerned by ongoing and pervasive acts of antisemitic
harassment and intimidation at the Massachusetts Institute of Technology (MIT). Failing to act decisively to ensure a safe learning environment for all students would be a grave dereliction of your responsibilities as President of MIT and Chair of the MIT Corporation.
This Congress will not stand idly by and allow an environment hostile to Jewish students to persist. The House believes that your institution is in violation of Title VI of the Civil Rights Act, and the inability or
unwillingness to rectify this violation through action requires accountability.
Postsecondary education is a unique opportunity for students to learn and have their ideas and beliefs challenged. However, universities receiving hundreds of millions of federal funds annually have denied
students that opportunity and have been hijacked to become venues for the promotion of terrorism, antisemitic harassment and intimidation, unlawful encampments, and in some cases, assaults and riots.
The House of Representatives will not countenance the use of federal funds to indoctrinate students into hateful, antisemitic, anti-American supporters of terrorism. Investigations into campus antisemitism by the Committee on Education and the Workforce and the Committee on Ways and Means have been expanded into a Congress-wide probe across all relevant jurisdictions to address this national crisis. The undersigned Committees will conduct oversight into the use of federal funds at MIT and its learning environment under authorities granted to each Committee.
• The Committee on Education and the Workforce has been investigating your institution since December 7, 2023. The Committee has broad jurisdiction over postsecondary education, including its compliance with Title VI of the Civil Rights Act, campus safety concerns over disruptions to the learning environment, and the awarding of federal student aid under the Higher Education Act.
• The Committee on Oversight and Accountability is investigating the sources of funding and other support flowing to groups espousing pro-Hamas propaganda and engaged in antisemitic harassment and intimidation of students. The Committee on Oversight and Accountability is the principal oversight committee of the US House of Representatives and has broad authority to investigate “any matter” at “any time” under House Rule X.
• The Committee on Ways and Means has been investigating several universities since November 15, 2023, when the Committee held a hearing entitled From Ivory Towers to Dark Corners: Investigating the Nexus Between Antisemitism, Tax-Exempt Universities, and Terror Financing. The Committee followed the hearing with letters to those institutions on January 10, 202
The French Revolution, which began in 1789, was a period of radical social and political upheaval in France. It marked the decline of absolute monarchies, the rise of secular and democratic republics, and the eventual rise of Napoleon Bonaparte. This revolutionary period is crucial in understanding the transition from feudalism to modernity in Europe.
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Dive into the world of AI! Experts Jon Hill and Tareq Monaur will guide you through AI's role in enhancing nonprofit websites and basic marketing strategies, making it easy to understand and apply.
5. Useful for identification of speciesAccording to the IUPAC (International Union of Pure and Applied Chemistry), it is the branch of science dealing with all aspects of mass spectroscopes and results obtained with these instruments.
6. Mass Spectrometry Contents Brief History of Mass Spectrometry Nobel prize pioneers Mass spectrometer Structural analysis and Fragmentation Patterns interpretation of mass spectrum Applications of mass spectrometry
7. 1897 1919 1934 1966 Mass Spectrometry Brief History of Mass Spectrometry J.J. Thomson. Discovered electrons by cathode rays experiment. Nobel prize in 1906. Francis Aston recognized 1st mass spectrometer and measure z/m of ionic compounds. First double focusing magnetic analyzer was invented by Johnson and Neil. Munson and Field described chemical ionization.
8. 1968 1975 1985 1989 Mass Spectrometry Electrospray Ionization was invented by Dole, Mack and friends. Atmospheric Pressure Chemical Ionization (APCI) was developed by Carroll and others. F. Hillenkamp, M.Karas and co-workers describe and coin the term matrix assisted laser desorption ionization (MALDI). w. Paul discovered the ion trap technique.
11. Mass Spectrometry Understanding Mass Spectrometry In a mass spectrometer, the same thing is happening, except it's atoms and molecules that are being deflected, and it's electric or magnetic fields causing the deflection. It's also happening in a cabinet that can be as small as a microwave or as large as a chest freezer.
12. Mass Spectrometry Mass spectrometer is similar to a prism. In the prism, light is separated into its component wavelengths which are then detected with an optical receptor, such as visualization. Similarly, in a mass spectrometer the generated ions are separated in the mass analyzer, digitized and detected by an ion detector.
18. Mass Spectrometry Direct infusion or injection sample introduction technique Frequently used due to high efficiently Used in coupling techniques like GC-MS and HPLC-MS
25. Mass Spectrometry Deprotonation Give net negative charge of 1- by removal of one proton Used for acidic species like phenols, carboxylic acid, sulfonic acid etc. Used in MALDI, APCI and ESI
26. Mass Spectrometry Cationization produces a charged complex by non-covalently adding a positively charged ion like alkali metal ion or ammonium ion to a neutral molecule. Used for Carbohydrates Used in MALDI, APCI and ESI
27. Mass Spectrometry Transfer of a charged molecule to the gas phase Cation from solution to gas Used in MALDI or ESI
28. Mass Spectrometry Electron ejection Electron is ejected to give positive ion Usually for non-polar compounds with low molecular weights like anthracene.
29. Mass Spectrometry Electron capture a net negative charge of 1- is achieved with the absorption or capture of an electron. Used for halogenated compounds
39. Mass Spectrometry Electrospray Ionization (ESI) The sample solution is sprayed from a region of the strong electric field at the tip of a metal nozzle maintained at a potential of anywhere from 700 V to 5000 V. The nozzle (or needle) to which the potential is applied serves to disperse the solution into a fine spray of charged droplets. Either dry gas, heat, or both are applied to the droplets at atmospheric pressure thus causing the solvent to evaporate from each droplet For example peptides, proteins, carbohydrates, small oligonucleotides, synthetic polymers, and lipids
43. Mass Spectrometry Atmospheric pressure photoionization (APPI) it generates ions directly from solution with relatively low background and is capable of analyzing relatively nonpolar compounds. APPI vaporized sample passes through ultra-violet light. APPI is much more sensitive than ESI or APCI.
44. Mass Spectrometry Matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS) the analyte is first co-crystallized with a large molar excess of a matrix compound, usually a UV-absorbing weak organic acid. Irradiation of this analyte-matrix mixture by a laser results in the vaporization of the matrix, which carries the analyte with it. The matrix plays a key role in this technique. The co-crystallized sample molecules also vaporize, but without having to directly absorb energy from the laser. Molecules sensitive to the laser light are therefore protected from direct UV laser excitation.
45. Mass Spectrometry Fast Atom Bombardment (FAB) Immobilized matrix is bombarded with a fast beam of Argon or Xenon atoms. Charged sample ions are ejected from the matrix and extracted into the mass analyzers Used for large compounds with low volatility (eg peptides, proteins, carbohydrates) Solid or liquid sample is mixed with a non-volatile matrix (eg glycerol, crown ethers, nitrobenzyl alcohol)
56. Mass Spectrometry Quadrupole Ion Trap The quadrupole ion trap typically consists of a ring electrode and two hyperbolic endcap electrodes. The motion of the ions induced by the electric field on these electrodes allows ions to be trapped or ejected from the ion trap. In the normal mode, the radio frequency is scanned to resonantly excite and therefore eject ions through small holes in the endcap to a detector. As the RF is scanned to higher frequencies, higher m/z ions are excited, ejected, and detected.
57. Mass Spectrometry Linear Ion Trap The linear ion trap differs from the 3D ion trap as it confines ions along the axis of a quadrupole mass analyzer using a two-dimensional (2D) radio frequency (RF) field with potentials applied to end electrodes. The primary advantage to the linear trap over the 3D trap is the larger analyzer volume lends itself to a greater dynamic ranges and an improved range of quantitative analysis.
58. Mass Spectrometry Double-Focusing Magnetic Sector the ions are accelerated into a magnetic field using an electric field. A charged particle traveling through a magnetic field will travel in a circular motion with a radius that depends on the speed of the ion, the magnetic field strength, and the ion’s m/z. A mass spectrum is obtained by scanning the magnetic field and monitoring ions as they strike a fixed point detector.
59. Mass Spectrometry Quadrupole Time-of-Flight Tandem MS Time-of-flight analysis is based on accelerating a group of ions to a detector where all of the ions are given the same amount of energy through an accelerating potential. Because the ions have the same energy, but a different mass, the lighter ions reach the detector first because of their greater velocity, while the heavier ions take longer due to their heavier masses and lower velocity. Hence, the analyzer is called time-of-flight because the mass is determined from the ions’ time of arrival. Mass, charge, and kinetic energy of the ion all play a part in the arrival time at the detector.
60. Mass Spectrometry Quadrupole Time-of-Flight MS Quadrupole-TOF mass analyzers are typically coupled to electrospray ionization sources and more recently they have been successfully coupled to MALDI. It has high efficiency, sensitivity, and accuracy as compared to Quadrupole and TOF analyzer.
61. Mass Spectrometry Detectors used in mass spectrometer Faraday Cup Photomultiplier Conversion Dynode Array Detector Charge (or Inductive) Detector Electron Multiplier
62. Mass Spectrometry Faraday Cup A Faraday cup involves an ion striking the dynode (BeO, GaP, or CsSb) surface which causes secondary electrons to be ejected. This temporary electron emission induces a positive charge on the detector and therefore a current of electrons flowing toward the detector. not particularly sensitive offering limited amplification of signal is tolerant of relatively high pressure. – Ions are accelerated toward a grounded “collector electrode” – As ions strike the surface, electrons flow to neutralize charge, producing a small current that can be externally amplified. – Size of this current is related to # of ions in – No internal gain -> less sensitive
63. Mass Spectrometry Photomultiplier Conversion Dynode the secondary electrons strike a phosphorus screen instead of a dynode. The phosphorus screen releases photons which are detected by the photomultiplier. Photomultipliers also operate like the electron multiplier where the striking of the photon on scintillating surface results in the release of electrons that are then amplified using the cascading principle. is not as commonly Life limit is high as compared to others.
64. Mass Spectrometry Array Detector detects ions according to their different m/z, has been typically used on magnetic sector mass analyzers. The primary advantage of this approach is that, over a small mass range, scanning is not necessary and therefore sensitivity is improved.
65. Mass Spectrometry Charge (or Inductive) Detector Charge detectors simply recognize a moving charged particle (an ion) through the induction of a current on the plate as the ion moves past Detection is independent of ion size.
66.
67. made up of a series (12 to 24) of aluminum oxide (Al2O3) dynodes
68. Used for increasing potentialIons strike the first dynode surface causing an emission of electrons. These electrons are then attracted to the next dynode held at a higher potential and therefore more secondary electrons are generated.
69. Mass spectrometer Vacuum in the Mass Spectrometer All mass spectrometers need a vacuum to allow ions to reach the detector without colliding with other gaseous molecules or atoms. If such collisions did occur, the instrument would suffer from reduced resolution and sensitivity.
74. Mass spectrometer Molecular ion (Parent ion) the peak corresponding to the mol wt of the compound The peak of an ion formed from the original molecule by electron ionization, by the loss of an electron, or by addition or removal of an anion or cation and also known as parent peak, radical peak.
75. Mass spectrometer Fragmentation peaks The peaks observed by fragments of compounds. The molecular ions are energetically unstable, and some of them will break up into smaller pieces. The simplest case is that a molecular ion breaks into two parts - one of which is another positive ion, and the other is an uncharged free radical. The uncharged free radical won't produce a line on the mass spectrum. Only charged particles will be accelerated, deflected and detected by the mass spectrometer. These uncharged particles will simply get lost in the machine - eventually, they get removed by the vacuum pump.
76. Mass Spectrometry Base peak The most intense (tallest) peak in a mass spectrum, due to the most abundant ion. Not to be confused with molecular ion: base peaks are not always molecular ion and molecular ion are not always base peaks.
88. Mass Spectrometry Homolytic bond cleavage A type of ion fragmentation in which a bond is broken by the transfer of one electron from the bond to the charged atom, the other electron remaining on its starting atom. The movement of one electron is signified by a fishhook arrow. The fragmentation of a ketone is shown in the figure.
89. Mass Spectrometry Heterolytic bond cleavage type of ion fragmentation in which a bond is broken by the transfer of a pair of electrons from the bond to the charged atom The movement of 2 electrons is signified by a double-barbed arrow and also referred to as charge-induced fragmentation.
90. Mass Spectrometry Alpha cleavage Alpha cleavage occurs on α-bonds adjacent to heteroatoms (N, O, and S). Charge is stabilized by heteroatom. Occurs only once in a fragmentation (cation formed is too stable to fragment further) For example in alcohols, aliphatic ethers, aromatic ethers, cyclic compounds and aromatic ketones etc.
91. Mass Spectrometry Beta-cleavage Fission of a bond two removed from a heteroatom or functional group, producing a radical and an ion. Also written as β-cleavage. For example allylic fragmentation.
92. Mass Spectrometry Inductive cleavage If an electron pair is completely transferred towards a centre of positive charge as a result of the inductive effect, shown schematically by the use of a double-headed arrow, then the ion will fragment by inductive cleavage. The figure illustrates this for a radical cation ether.
93. Mass Spectrometry Retro Diels-Alder Cleavage A multicentered ion fragmentation which is the reverse of the classical Diels-Alder reaction employed in organic synthesis that forms a cyclic alkene by the cycloaddition of a substituted diene and a conjugated diene. In the retro reaction, a cyclic alkene radical cation fragments to form either a diene and an alkene radical cation or a diene radical cation and an alkene. Depending on the substituents present in the original molecule, the more stable radical cation will dominate.
94. Mass Spectrometry McLafferty rearrangement An ion fragmentation characterised by a rearrangement within a six-membered ring system. The most usual configuration is for a radical cation formed by EI to undergo the transfer of a γ- hydrogen atom to the ionisation site through a ring system as shown here. The distonic radical cation so formed can break up by radical-site-induced (α), or charged site-induced fragmentation as shown in the figure. For example ketones, carboxylic acid and esters.
95. Mass Spectrometry Ortho effect The interaction between substituents oriented ortho, as opposed to para and meta, to each other on a ring system, can create specific fragmentation pathways. This permits the distinction between these isomeric species. The diagram shows a case in which only the ortho isomer can undergo the rearrangement.
96. Mass Spectrometry Onium Reaction Onium Ion: A hypervalent species containing a non-metallic element such as the methonium ion CH5+. It includes ions such as oxonium, phosphonium, and nitronium ions. Mostly observed in cationic fragments containing a heteroatom as charge carrier, e.g. oxonium, ammonium, phosphonium and sulphonium ions. The onium reaction is not limited to alkyl substituents acyl groups can also undergo the onium reaction
97. Mass Spectrometry CO Elimination Cyclic unsaturated carbonyl compounds and cationic carbonyl fragments which resulted from an a-cleavage tend to eliminate CO . If there is more than one CO group present sequential elimination of all CO groups is possible. From carbonyl compounds CO elimination reaction takes place like in aldehyde, ketones and phenols etc
103. Mass Spectrometry Mass spectra (examples) Alkanes Strong M+ (but intensity decreases with an increase of branches. Carbon-carbon bond cleavage loss of CH units in series: M-14, M-28, M-42 etc
105. Mass Spectrometry Cycloalkanes Strong M+, strong base peak at M-28 (loss of ethene) A series of peaks: M-15, M-28, M-43 etc Methyl, ethyl, propyl with an additional hydrogen give peaks
106. Mass Spectrometry Alkenes Strong M+ Fragmentation ion has formula CnH2n+ and CnH2n-1 -Cleavage A series of peaks: M-15, M-29, M-43, M-57 etc
107. Mass Spectrometry Alkynes Strong M+ Strong base peak at M-1 peak due to the loss of terminal hydrogen Alpha cleavage
108. Mass Spectrometry Aromatic Hydrocarbons Strong M+ Loss of hydrogen gives base peak McLafferty rearrangement Formation of benzyl cation or tropylium ion
109. Mass Spectrometry Alcohols M+ weak or absent Loss of alkyl group via a-cleavage Dehydration (loss of water) gives peak at M-18
110. Mass Spectrometry Phenols Strong M+ M-1 due to hydrogen elimination M-28 due to loss of CO M-29 due to loss of HCO (formyl radical)
111. Mass Spectrometry Ethers M+ weak but observable Loss of alkyl radical due to a-cleavage B-cleavage( formation of carbocation fragments through loss of alkoxy radicals) C-O bond cleavage next to double bond Peaks at M-31, M-45, M-59 etc
112. Mass Spectrometry Aldehyde M+ weak, but observable (aliphatic) Aliphatic : M-29, M-43 etc McLafferty rearrangement is common gives the base peak A-cleavage B-cleavage
113. Mass Spectrometry Aldehyde M+ strong (aromatic) Aromatic: M-1 (loss of hydrogen) M-29 (loss of HCO) McLafferty rearrangement is common A-cleavage B-cleavage
114. Mass Spectrometry Ketones Strong M+ A series of peaks M-15, M-29, M-43 etc Loss of alkyl group attached to the carbonyl group by a-cleavage Formation of acylium ion (RCO+) McLafferty rearrangement
115. Mass Spectrometry Esters M+ weak but generally observable Loss of alkyl group attached to the carbonyl group by a-cleavage Formation of acylium ion (RCO+) McLafferty rearrangement Acyl portion of ester OR+ Methyl esters: M-31 due to loss of OCH3 Higher esters: M-32, M-45, M-46, M-59, M-60, M-73 etc
116. Mass Spectrometry Carboxylic acids Aliphatic carboxylic acids: M+ weak but observable A-cleavage on either side of C=O M-17 due to loss of OH M-45 due to loss of COOH McLafferty rearrangement gives base peak
117. Mass Spectrometry Aromatic carboxylic acids: M+ Strong A-cleavage on either side of C=O M-17 due to loss of OH M-18 due to loss of HOH M-45 due to loss of COOH McLafferty rearrangement gives base peak
120. Mass Spectrometry Nitro Compounds M+ seldom observed Loss of NO+ give visible peak Loss of NO2+ give peak
121. Mass Spectrometry Alkyl chloride and alkyl bromides Strong M+2 peak For Cl M/M+2 = 3:1 F or Br M/M+2 = 1:1 A-cleavage Loss of Cl or Br Loss of HCl or HBr
132. Mass Spectrometry Protein characterization Mass spectrometry is an important emerging method for the characterization of proteins. The two primary methods for ionization of whole proteins are electrospray ionization (ESI) and (MALDI). Space exploration Mass spectrometers are also widely used in space missions to measure the composition of plasmas. For example, the Cassini spacecraft carries the Cassini Plasma Spectrometer (CAPS),[44] which measures the mass of ions in Saturn's magnetosphere. Isotope dating and tracking Mass spectrometry is also used to determine the isotopic composition of elements within a sample. Differences in mass among isotopes of an element are very small, and the less abundant isotopes of an element are typically very rare, so a very sensitive instrument is required. These instruments, sometimes referred to as isotope ratio mass spectrometers (IR-MS).
133. Mass Spectrometry Molecular weight Molecular weight can be determined by mass spectrometry. Actual number of carbons, hydrogen, oxygen etc By using relative intensities(peak hight), we can easily calculated the actual numbers of C,H,O etc atoms. Bonding Bonding can be studied by fragmentation patterns for example, beta cleavage is possible only if double bonds or heteroatom present. Reaction mechanism Mass spectrometry is best technique to study reaction mechanism and intermediates produced in reaction, for example, in carboxylic acid and alcohols a peak at M-18 indicates that water is produced.
134. Mass Spectrometry Determination of Elements Bulk materials such as steel or refractory metals, elements are determined by low-resolution glow-discharge mass spectrometry. High-resolution GDMS has been used to study semiconductor materials. GDMS is considered virtually free of matrix effects. Detection limits in ICPMS as in Table
135. Mass Spectrometry Species Analysis Heavy metals in the environment are stored in complexes with humic acids, can be converted by microbes in different complexes, and can be transported in live animals and humans. This applies to many elements such as lead, mercury, arsenic, astatine, tin and platinum For example, tin and lead alkylates established in soil, water or muscle tissue by GC / MS after exhaustive alkylation or thermal spray, and ICP-LC/MS API methods.
136. Mass Spectrometry Environmental Chemistry the analysis of trace elements and compounds in environmental samples like air, water, soil etc because of its detection power, specificity and structural analysis functions Generally, sample preparation is at least one type of chromatography coupled with MS either offline or online like GCMS
MASS SPECTROMETRYMass spectrometry is a powerful analytical technique that is used to identify unknown compounds, to quantify known compounds, and to elucidate the structure and chemical properties of molecules. It is the smallest scale in the world, not because of the mass spectrometer’s size but because of the size what it weighs...molecules. According to the IUPAC (International Union of Pure and Applied Chemistry), it is the branch of science dealing with all aspects of mass spectroscopes and results obtained with these instruments. The information given by mass spectrometry is sometimes sufficient, frequently necessary, and always useful for identification of species.
Mass Spectrometry was started by J.J. Thomson. Until 1897, scientists believed atoms were indivisible; the ultimate particles of matter, but Thomson proved them wrong when he discovered that atoms contained particles known as electrons. He concluded this by his experiments on cathode rays. He found that the rays could be deflected by an electric field (in addition to magnetic fields, which was already known). By comparing the deflection of a beam of cathode rays by electric and magnetic fields he was able to measure the particle's mass. This showed that cathode rays were matter, but he found that the particles were about 2000 times lighter than the mass of the lightest atom, hydrogen. He concluded that the rays were composed of very light negatively charged particles which he called electron. He also concluded that neon is composed of two isotopes and them which was the first example of mass spectrometry. On his discovery he was awarded Nobel Prize in 1906.In 1919, Thomson, with the help of his student Francis Aston (who would go on to win his own Nobel Prize in Chemistry in 1922), built what later would be recognized as the first mass spectrometer to measure the masses of charged atoms. In their first mass spectrometer they measure the charge to mass ratio (z/m) for several ionic species. In the expression z/m, z is the charge number, i.e. the total charge on an ion divided by the elementary charge (e), and m is the nucleon number, i.e. the sum of the total number of protons and neutrons in an atom, molecule or ion. In modern mass spectrometry, the parameter measured is m/z, rather than z/m: the unit of m/z was recently designated the Thomson (Th).This instrument used gas discharge tubes to generate ions, which were then passed through parallel electric and magnetic fields. The ions were deflected into parabolic trajectories and then detected on a photographic plate.In 1934, First double focusing magnetic analyzer was invented by Johnson E.G., Nier A.O. In 1966, Munson and Field described chemical ionization (CI). One of the first soft ionization techniques
In 1968, Electrospray Ionization was invented by Dole M., Mack L.L., Hines R.L., Mobley R.C., Ferguson L.D., Alice M.B. In 1975, Atmospheric Pressure Chemical Ionization (APCI) was developed by Carroll D.I., Dzidic I., Stillwell R.N., Haegele K.D., Horning E.C.In 1985, Franz Hillenkamp, Michael Karas and co-workers describe and coin the term matrix-assisted laser desorption ionization (MALDI).In 1989, Wolfgang Paul receives the Nobel Prize in Physics "for the development of the ion trap technique"
An instrument which measures the ratio of mass to the number of charges of ions produced from elements and compounds. It is also of value in performing fundamental studies of the properties of gaseous ions.
Basic components of mass spectrometerFour basic components are, for the most part, standard in all mass spectrometers: a sample inlet, an ionization source, a mass analyzer and an ion detector. Some instruments combine the sample inlet and the ionization source, while others combine the mass analyzer and the detector. However, all sample molecules undergo the same processes. Sample molecules are introduced into the instrument through a sample inlet. Once inside the instrument, the sample molecules are converted to ions in the ionization source, before being electrostatically propelled into the mass analyzer. Ions are then separated according to their m/z within the mass analyzer. The detector converts the ion energy into electrical signals, which are then transmitted to a computer.