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Zoo ZooMass number:-: Mass number:- The Mass number (A), also called atomic mass number or nucleon number is the total number of protons and neutrons in an atomic nucleus. 11-Apr-12 Solairajan 3Example:-: Example:- Carbon atom have 6 protons and 6 neutrons in the centre of the nucleus, 2 electrons situated in the inner orbital where as other 4 electrons are outside the orbital. We can represent carbon atom like 11-Apr-12 Solairajan 4 Mass Number(A) No. of protons(Z) Carbon Atom:-Common elements and Mass number: Common elements and Mass number 11-Apr-12 Solairajan 5PowerPoint Presentation: Introduction Basic principles Instrumentation Ion formation & types Fragmentation process Fragmentation pattern 11-Apr-12 Solairajan 6PowerPoint Presentation: Chemical ionisation MS (CIMS) Field ionisation MS (FIMS) Fast atom bombardment MS (FAB MS) Matrix assisted laser desorption/ ionisation MS (MALDI-MS) Gas chromatography MS (GC-MS) Interpretation of spectra Applications in pharmacy 11-Apr-12 Solairajan 7PowerPoint Presentation: WHAT IS MASS SPECTROMETRY ? Mass spectrometry is an instrumental technique in which sample is converted to rapidly moving positive ions by electron bombardment and charged particles are separated according to their masses. WHAT IS MASS SPECTRUM ? Mass spectrum is a plot of relative abundance against the ratio of mass/charge(m/e). 11-Apr-12 Solairajan 8Simple mass spectrometry: Simple mass spectrometry 11-Apr-12 Solairajan 9PowerPoint Presentation: Three principle behind mass spectra To measure relative molecular masses. To know the fragmentation of the molecules. Comparison of mass spectra with known compounds . 11-Apr-12 Solairajan 10BASIC PRINCIPLES: BASIC PRINCIPLES 11-Apr-12 Solairajan 11PowerPoint Presentation: Loss of electron from a molecule leads to radical cation . 11-Apr-12 Solairajan 12 e- Molecular ion 15 eV 70 eVPowerPoint Presentation: Electron removed from molecule orbital having lowest ionization potential (IP). In general n < π < σ 1 eV = 23 Kcal/mol 11-Apr-12 Solairajan 13 Compounds Ionization potential CH 4 12.6 eV C 2 H 4 10.52 eV CH 3 NH 2 10.3 eVComponents of mass spectrometer: Components of mass spectrometer Inlet system Ion source Ionisation methods Mass Analysers Ion Detectors Vacuum System 11-Apr-12 Solairajan 14PowerPoint Presentation: 11-Apr-12 Solairajan 15INSTRUMENTATION: INSTRUMENTATION 11-Apr-12 Solairajan 16 Inlet System: Inlet System SOLIDS SAMPLES with lower vapour pressure directly inserted into the ionization chamber and volatilization is controlled by heating the probe . LIQUIDS are handled by hypodermic needles injection through a silicon rubber dam . GASES SAMPLES are leaked into the ionisation chamber directly by the help of mercury manometer. 11-Apr-12 Solairajan 17 Inlet systemPowerPoint Presentation: The ion source is the part of the mass spectrometer that ionizes the material under analysis (the analyte ). The ions are then transported by magnetic or electric fields to the mass analyzer. Molecular ions are formed when energy of the electron beam reaches to 10-15 eV . Fragmentation of the ion reaches only at higher bombardment energies at 70 eV . 11-Apr-12 Solairajan 18 Ion sources:- IonisationPowerPoint Presentation: Ionisation Method Divided Into Two Categories . Gas phase ionisation (gases and vapour ) S amples are ionised outside the ion source. T his technique include, 1.Electron impact ionization (EIS) 2.Chemical ionization.(CI) 3.Field ionisation .(FI) Desorption technique (liquid and solid) S amples are ionised inside the ion source. T his technique include, 1. Field desorption.(FD) 2. Fast atom bombardment.(FAB) 3. Laser desorption .(LD) 11-Apr-12 Solairajan 19 IonisationIonizing agent in MS: Ionizing agent in MS 11-Apr-12 Solairajan 20 IonisationIONIZATION METHOD IN MS: IONIZATION METHOD IN MS 11-Apr-12 Solairajan 21 IONISATION METHOD COMPOUNDS MASS RANGE Electron impact ionisation Thermally volatile and stable 500 Da Chemical ionisation Thermally volatile and Stable 500 Da Electro spray ionisation Polar and Basic 70000 Da Fast atom bombardment Peptides 7000 Da Field ionisation Thermally volatile 1000 Da MALDI Large Biomolecules 3,00,000 Da Plasma desorption Neutral compounds 500 Da APCI Thermally liable 1000 Da SIMS Same as FAB 300-13000 Da Laser desorption Elemental analysis 500 DaElectron impact ionisation:-: Electron impact ionisation :- A beam of electrons passes through a gas-phase sample and collides with neutral analyte molecules (M) to produce a positively charged ion or a fragment ion. Generally electrons with energies of 70 eV are used to form a fragment ions. The positive ions are collected in focusing plates and passed to mass analyzer. 11-Apr-12 Solairajan 22 IonisationPowerPoint Presentation: 11-Apr-12 Solairajan 23 IonisationElectrospray ionisation:-: Electrospray ionisation :- The ESI source consists of a very fine needle and a series of skimmers. A sample solution is sprayed into the source chamber to form droplets. When droplets carry charge exit the capillary end, as the solvent evaporates, the droplets disappear leaving highly charged analyte molecules. 11-Apr-12 Solairajan 24 IonisationChemical ionisation:-: Chemical ionisation :- Chemical Impact Ionisation between interactions of sample with large amount of reagent gas. Commonly used reagent gases include methane,ammonia,isobutane . Oxygen and hydrogens are used in Negative ion chemical ionisation in MS. 11-Apr-12 Solairajan 25 IonisationPowerPoint Presentation: The vaporised sample is introduced into the mass spectrometer with an excess of a reagent gas (methane) at pressure of about 1 torr . The excess carrier gas is ionized by electron impact to the primary ions CH 4 .+ and CH 3 + . These may react with the excess methane to give secondary ions. 11-Apr-12 Solairajan 26 CI contd … IonisationPowerPoint Presentation: In this method the molecule pass through sharp metal anode carrying an electric field of 10 10 v m -1 Electrons are analysed in primary focusing cathode slit. ADV :- abundance of molecular ions. DISADV :- lower resolution. 11-Apr-12 Solairajan 27 Field ionisation :- IonisationPowerPoint Presentation: Useful for nonvolatile and thermolabile compounds. Sample is applied to field ion emitter and the solvent allowed to evaporate. Evaporated sample that leads to chemical ionisation or EIS. Example:- Nucleotides & Quarternary ammonium compounds . 11-Apr-12 Solairajan 28 Field desorption:- IonisationPowerPoint Presentation: Argon gas ionised by hot filament and focused beam that bombards the sample . Beam impinges the sample, a series of molecular reactions occur and analyse in MS analyser . Ex:- Insulin,Amino glycosides,Phospholipids . 11-Apr-12 Solairajan 29 Fast atom bombardment:- IonisationPowerPoint Presentation: Sample is coated with a high energetic fragment Californium 252. This fission fragment desorbs positive,negative , and neutral molecules. 252 cf generates 10 12 power at 10,000k, this may ionise the target molecule. This method involves the interaction of laser beam with sample to produce both vaporisation and ionisation . The vaporised sample passed to mass spectrometers for analysis. Appl :-used for elemental analysis . 11-Apr-12 Solairajan 30 Plasma desorption:- Laser desorption:- IonisationPowerPoint Presentation: MALDI is a LIMS method of vaporizing and ionizing and sample molecules are dispersed in a solid matrix such as nicotinic acid. A UV laser pulse ablates the matrix which carries some of the large molecules into the gas phase in an ionized form so they can be extracted into a mass spectrometer. 11-Apr-12 Solairajan 31 MALDI MALDI:- Ionisation: Atmospheric pressure chemical ionisation (APCI) is an analogous ionisation method to chemical ionisation (CI). Corona discharge is used to ionize the analyte in the atmospheric pressure region. 11-Apr-12 Solairajan 32 APCI:- IonisationSIMS:- : SIMS:- Secondary ion mass spectrometry (SIMS) is based on the observation that charged particles (Secondary Ions) are ejected from a sample surface when bombarded by a primary beam of heavy particles. Primary beam species useful in SIMS include Cs+, O2+, O , Ar +, and Ga + 11-Apr-12 Solairajan 33 IonisationPowerPoint Presentation: An ion, after leaving ion source, the ions are separated according to their m/e ratio. In this area, the ions are accelerated by both electrostatic and magnetically Types:- Magnetic sector mass analysers Double focussing analysers Quadrupole mass analysers Time of Flight analysers (TOF) Ion trap analyser Ion cyclotron analyser 11-Apr-12 Solairajan 34 MASS ANALYSERS Mass AnalyzerPowerPoint Presentation: m/z= H 2 r 2 /2V H Magnetic field R Radius of the curvature V Applied voltage 11-Apr-12 Solairajan 35 Magnetic sector mass analyser :- Mass AnalyzerDOUBLE FOCUSSING ANALYSERS: DOUBLE FOCUSSING ANALYSERS It contains two analysers namely Electrostatic analyser Magnetic sector analyser . 11-Apr-12 Solairajan 36 Mass AnalyzerQUADRUPOLE MASS ANALYSER: QUADRUPOLE MASS ANALYSER The quadrupole consists of two pairs of parallel rods with applied DC and RF voltages. Ions are scanned by varying the DC/ Rf quadrupole voltages. 11-Apr-12 Solairajan 37 Mass AnalyzerPowerPoint Presentation: 11-Apr-12 Solairajan 38 Mass AnalyzerPowerPoint Presentation: TOF analyzer – ions are accelerated through a flight tube and the time of fight to the detector is measured. Typical flight times are 1 to 50 μ s. 11-Apr-12 Solairajan 39 TIME OF FLIGHT ANALYSER Mass AnalyzerPowerPoint Presentation: The quadrupole ion trap typically consists of a ring electrode and two hyperbolic end cap electrodes. As the radio frequency voltage is increased, the orbits of heavier ions become stabilised,and passed into the detector. 11-Apr-12 Solairajan 40 ION TRAP ANALYSER Mass AnalyzerPowerPoint Presentation: 11-Apr-12 Solairajan 41 ION CYCLOTRON ANALYSER:- Mass Analyzer Fourier transform-ICR mass spectrometry, is a type of mass analyzer for determining the mass-to-charge ratio (m/z) of ions based on the cyclotron frequency of the ions in a fixed magnetic field. The ions are trapped in a Penning trap(a magnetic field with electric trapping plates) where they are excited to a larger cyclotron radius by an oscillating electric field perpendicular to the magnetic field.PowerPoint Presentation: The excitation also results in the ions moving in phase (in a packet). The signal is detected as an image current on a pair of plates which the packet of ions passes close to as they cyclotron. The resulting signal is called a free induction decay (FID), transient or interferogram that converts signal. The useful signal is extracted from this data by performing a Fourier transform to give a mass spectrum. 11-Apr-12 Solairajan 42PowerPoint Presentation: 11-Apr-12 Solairajan 43PowerPoint Presentation: Faraday cup Electron Multiplier photomultiplier Micro Channel Plate 11-Apr-12 Solairajan 44 DETECTORS:- DetectorPowerPoint Presentation: The basic principle is that the incident ion strikes the dynode surface which emits electrons and induces a current which is amplified and recorded. The dynode electrode is made of a secondary emitting material like CsSb, GaP or BeO. It is ideally suited to isotope analysis. 11-Apr-12 Solairajan 45 Faradaycup Faradaycup :- DetectorPowerPoint Presentation: Electron multipliers are the most common especially when positive and negative ions need to be detected on the same instrument. Dynodes made up of copper-beryllium which transduces the initial ion current ,and electron emitted by first dynode are focused magnetically from dynode to the next. Final cascade current is amplified more than million times . 11-Apr-12 Solairajan 46 Electron multipliers Electron Multipliers DetectorPowerPoint Presentation: The dynode consists of a substance( a scintillator ) which emits photons(light). The emitted light is detected by photo multiplier tube and is converted into electric current. These detectors are useful in studies on metastable ions 11-Apr-12 Solairajan 47 Photomultipliers:- DetectorPowerPoint Presentation: 11-Apr-12 Solairajan 48 Micro channel Plate:- DetectorPowerPoint Presentation: 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. 11-Apr-12 Solairajan 49 Vacuum system:-TYPES OF PEAKS IN MS: TYPES OF PEAKS IN MS Molecular ion peak Fragment ions peak Rearrangement ions peak Metastable ion peaks Multicharged ions Base peak Negative ion peak Molecular ion Peak:- When a sample is bombarded with electrons of 9 to 15 eV energy, the molecular ion is produced, by loss of single electron. M e - M + + 2 e - 11-Apr-12 Solairajan 50PowerPoint Presentation: Fragment ions Peak:- when an energy is given further more upto 70 eV , fragment ions produced, it have lower mass number. Rearrangement ion Peak:- Recombination of fragment ion is known as Rearrangement Peaks. Metastable ion Peak:- The ions resulting from the decomposition between the source region and magnetic analyser are called as Meta stable ions.These appear as broad peaks called Metastable ion Peaks. Multicharged ions:- Ions may exist with 2 or 3 charges instead of usual single charge.The peaks due to these charged ions are known as Multicharged ion peaks. 11-Apr-12 Solairajan 51PowerPoint Presentation: Base Peak:- The largest peak in the mass spectrum corresponding to the most abundant ion or most intense peak in the spectrum is called as Base Peak. Negative ion Peak:- Negative ions are formed from electron bombardment of sample. These results due to the capture of electron by a molecule during collision of molecules 11-Apr-12 Solairajan 52 Fragment ion peakFRAGMENTATION: FRAGMENTATION Fragmentation is a type of chemical dissociation. Fragmentation takes place by a process of heterolysis or homolysis . Types of Fragmentation:- Collision induced dissociation(CID) Electron capture dissociation(ECD) Electron transfer dissociation(ETD) Electron detachment dissociation(EDD) Photo dissociation Infrared multiphoton dissociation(IRMPD) Blackbody infrared radiative dissociation(BIRD) Surface induced dissociation(SID) Charge remote fragmentation Higher energy C-trap dissociation(HCD) 11-Apr-12 Solairajan 53PowerPoint Presentation: Collision Induced Dissociation Molecular ions are accelerated by electrical potential to high kinetic energy and then allowed to collide with neutral molecules like He,N or Ar . Collision between these molecules leads to bond breakage and formation of fragment ions. These fragment ions are analysed by mass spectrometer. Example:- Triple quadrupole spectrometer produces CID fragments. 11-Apr-12 Solairajan 54PowerPoint Presentation: 11-Apr-12 Solairajan 55 SORI-CID: -(Sustained Off-Resonance Irradiation Collision-Induced Dissociation ) It is one of CID technique used in Fourier transform ion cyclotron resonance mass spectrometry. In this method accelerating ions in cyclotron motion and increasing the pressure resulting collisions produce CID fragments.Electron Capture Dissociation:-: Electron Capture Dissociation:- It is a method of fragmenting gas phase ions for tandem mass spectrometric analysis (structural elucidation). ECD involves the direct introduction of low energy electrons to trapped gas phase ions. Electron-capture dissociation typically involves a multiply protonated molecule M interacting with a free electron to form an odd-electron ion. 11-Apr-12 Solairajan 56Electron Transfer Dissociation:-: Electron Transfer Dissociation :- ETD induces fragmentation of cations by transferring electrons to them . Example:-peptides or proteins . Electron Detachment Dissociation:- EDD is a method for fragmenting anionic species in mass spectrometry. 11-Apr-12 Solairajan 57Photo Dissociation:-: Photo Dissociation:- Photodissociation is a chemical reaction in which a chemical compound is broken down by photons . IRMPD:- Absorption of multiple infra red photons by a molecule and leads to dissociation. BIRD:- Long interaction of molecule with radiation field like carbon dioxide laser . Surface-induced dissociation:-(SID) It is a technique used in mass spectrometry to fragment molecular ions in the gas phase by collision of an ion with a surface under high vacuum . 11-Apr-12 Solairajan 58PowerPoint Presentation: Charge Remote Fragmentation:- It is a type of covalent bond breaking that occurs in a gas phase ion in which the cleaved bond is not adjacent to the location of the charge. This fragmentation can be observed using tandem mass spectrometry . Higher-energy C-trap dissociation:- (HCD) It is a fragmentation technique, used for peptide modification analysis. Immonium ions generated via HCD pinpoint modifications such as phospho tyrosine. An added octopole collision cell facilitates de novo sequencing. 11-Apr-12 Solairajan 59Fragmentation of the Molecular ion: Fragmentation of the Molecular ion Fragmentation of a molecular ion, M, produces a radical and a cation . -Only the cation is detected by MS. 11-Apr-12 Solairajan 60Description of Fragmentation process:- : Description of Fragmentation process:- Fragmentation of the odd electron molecular ion (M .+ ) may occur by Homolytic or Heterolytic cleavage of a single bond. 11-Apr-12 Solairajan 61Mass interpretation: Mass interpretation Fragmentation rules Mclafferty rearrangement Alpha cleavage Beta cleavage Nitrogen rule Retro diels alder reaction IHD 11-Apr-12 Solairajan 62Fragmentation rules:- (9 rules): Fragmentation rules:- (9 rules) Rule:-1 The height of the M .+ peak decreases with increasing degree of branching. 11-Apr-12 Solairajan 63Rule:-2 : Rule:-2 The height of the M .+ Peak decreases with increasing molecular weight. Example:- Fatty molecules, steroids. 11-Apr-12 Solairajan 64Rule:-3: Rule:-3 The cleavage is favored at alkyl substituted carbons leads to formation of a carbocation . 11-Apr-12 Solairajan 65Rule:-4: Rule:-4 Double bonds, cyclic structures and aromatic rings stabilize M .+ and increase the probability of its appearance. 11-Apr-12 Solairajan 66 Molecular ion peak & Base peakRule:-5: Rule:-5 Double bonds favor allylic cleavage to give the resonance stabilized cation. 11-Apr-12 Solairajan 67Rule:-6: Rule:-6 Saturated rings tend to lose alkyl side chains at the α bond (see rule 3) Unsaturated rings can undergo a Retro-Diels-Alder reaction 11-Apr-12 Solairajan 68Rule:-7: Rule:-7 Alkyl substituted aromatic compounds are cleaved preferably at the β bond to the ring, giving the resonance stabilized benzyl ion (or) tropyllium ion. 11-Apr-12 Solairajan 69Rule:-8: Rule:-8 C-C bonds next to hetero atom are frequently cleaved, leaving the charge on the hetero atom (resonance stabilization). 11-Apr-12 Solairajan 70Rule:-9: Rule:-9 Cleavage is often associated with elimination of small stable, neutral molecules, such as CO,olefins,water,ammonia,H 2 S,HCN,ketene or alcohols (often with rearrangements) Ex:- Mclafferty rearrangement 11-Apr-12 Solairajan 71Mclafferty Rearrangement:-: Mclafferty Rearrangement:- Mclafferty arrangement can occur in ketones,aldehydes,carboxylic acids, and esters . In this rearrangement a radical center in molecular ion derived from a lone pair or pi bond, removes hydrogen from the Gamma position( γ ) , a pi bond is formed between the β and γ position, and the bond between the α and β positions is broken. 11-Apr-12 Solairajan 72α cleavage: α cleavage 11-Apr-12 Solairajan 73 Alpha cleavage in mass spectrometry is a characteristic fragmentation of the molecular ion derived from carbonyl compounds, in which the bond linking the carbonyl carbon to the atom occupying an alpha position breaks. It is an expected pathway for carbonyl compounds,ethers,halides,alcohols,and amines .PowerPoint Presentation: 11-Apr-12 Solairajan 74β cleavage: β cleavage Beta cleavage in mass spectrometry is a characteristic fragmentation of the molecular ion derived from some organic compounds, most notably alcohols, ethers, and amines, in which the bond connecting alpha- and beta-carbons break . 11-Apr-12 Solairajan 75PowerPoint Presentation: 11-Apr-12 Solairajan 76Retro-Diels-Alder reactions:-: Retro-Diels-Alder reactions:- Retro Diels-Alder fragmentation occurs in 3-cyano-cyclohexene, lets first look at the fragmentation of cyclohexene . First ionization occurs and electrons from the double bond transfer to an adjacent carbon and an electron from the bond between the 3 and 4 carbons transfers to form a second double bond that is conjugate with the first one. These rearrangements cleave the molecule between the 3 and 4 carbon and 5 and 6 (where another electron is transferred to form a double bond between the 4 and 5 carbons). This leaves an olefin and a diene . 11-Apr-12 Solairajan 77PowerPoint Presentation: 11-Apr-12 Solairajan 78 6 1 2 3 4 5 4 5 Diene OlefinNitrogen rule:-: Nitrogen rule:- The nitrogen rule states, that a molecule that has no or even number of nitrogen atoms has an even nominal mass , whereas a molecule that has an odd number of nitrogen atoms has an odd nominal mass . 11-Apr-12 Solairajan 79 Example:-1 Example:-2Contd….: Contd …. The molecular ion appears at m/z 121, indicating an odd number of nitrogen atoms in the structure . 11-Apr-12 Solairajan 80 Odd number of molecular ionIHD:-: IHD:- In a hydrocarbon where all carbon atoms have only single bonds and no rings are involved, the compound would have maximum number of H atoms. If any of the bonds are replaced with double or triple bonds, there would be deficiency of H atoms. By calculating the index of hydrogen deficiency(IHD), we can calculate molecular formula and how many multiple bonds and rings are involved. IHD is also called the Degree of Unsaturation . A double bond and ring each counts as one IHD. A triple bond counts as two IHD . 11-Apr-12 Solairajan 81PowerPoint Presentation: 11-Apr-12 Solairajan 82 Example:-1 Example:-2 CH2=CH2PowerPoint Presentation: 11-Apr-12 Solairajan 83Mass Spectrum of compounds:-: Mass Spectrum of compounds:- Alkane :- 11-Apr-12 Solairajan 84 Base Peak Molecular ion peakPowerPoint Presentation: Fragmentation of Cyclo Hexane:- C 6 H 12 + = 84 ( Molecular ion Peak ), C 4 H 8 + = 56 ( Base Peak ), (M-28) C 6 H 9 + = 69 (Fragment ion Peak), (M-15) C 3 H 7 + = 43 (Fragment ion Peak), (M-41) C 2 H 5 + = 29 (Daughter ion Peak), CH 3 + = 15 (Daughter ion Peak). 11-Apr-12 Solairajan 85Alcohol: Alcohol Possible Fragmentations are:- Mol.wt-46 C2H5OH+ =46 (Molecular ion peak) CH 3 O + = 31 (Base Peak) CHO + = 27 (Fragment ion Peak) CH 3 + = 15 (Daughter ion Peak) 11-Apr-12 Solairajan 86 Base Peak Molecular ion Peak Fragment ion Peak Daughter ion PeakAldehyde:-: Molecular formula:-C 6 H 12 O Molecular Weight:-100 C 6 H 12 O + = 99 (Molecular ion Peak) C 3 H 8 + = 44 (Base Peak) C 4 H 9 + = 57 (Fragment ion Peak) C 2 H 5 + = 29 (Fragment ion Peak) 11-Apr-12 Solairajan 87 Aldehyde :- Fragment ion Peak Base Peak- Mclafferty rearrangement Molecular ion Peak- α cleavagePowerPoint Presentation: 11-Apr-12 Solairajan 88Amide:-: Amide:- Molecular wt :- 87, Molecular formula :- C 4 H 9 NO C 4 H 9 NO + = 87 (Molecular ion Peak), C 2 H 5 NO + = 59 (Base Peak) 11-Apr-12 Solairajan 89 Fragment ion Peak- α , β cleavage Base Peak- Mclafferty rearrangement Molecular ion Peak- β cleavagePowerPoint Presentation: 11-Apr-12 Solairajan 90Amine:-: Amine:- Molecular wt:-59 Mol.formula :-C 3 H 9 N 11-Apr-12 Solairajan 91 Molecular ion Peak- β -H transfer Base Peak- β -H transferPowerPoint Presentation: 11-Apr-12 Solairajan 92Ester: Ester Mol.wt :-102, Mol.formula :-C 5 H 10 O 2 11-Apr-12 Solairajan 93 Base Peak- α cleavage Molecular ion Peak α -cleavagePowerPoint Presentation: 11-Apr-12 Solairajan 94Ether: Ether Mol.wt :-130 Mol.formula :-C 8 H 18 O 11-Apr-12 Solairajan 95 Base Peak-ipso cleavage α cleavage Molecular ion Peak- α cleavagePowerPoint Presentation: 11-Apr-12 Solairajan 96GC-MS: GC-MS Gas chromatography–mass spectrometry ( GC-MS ) is a method that combines the features of gas-liquid chromatography and mass spectrometry to identify different substances within a test sample. Applications of GC-MS include :- Drug detection, Fire investigation, Environmental analysis, Explosives investigation, and Identification of unknown samples. 11-Apr-12 Solairajan 97GC-MS: GC-MS 11-Apr-12 Solairajan 98Tandem MS:-: Tandem MS:- What is Tandem MS :- - Uses 2 (or more) mass analyzers in a single instrument. -One purifies the analyte ion from a mixture using a magnetic field. -The other analyzes fragments of the analyte ion for identification and quantification . 11-Apr-12 Solairajan 99PowerPoint Presentation: 11-Apr-12 Solairajan 100PowerPoint Presentation: Tandem mass spectrometry , also known as MS/MS or MS 2 , involves multiple steps of mass spectrometry selection, with some form of fragmentation occurring in between the stages. 11-Apr-12 Solairajan 101Components of Tandem Mass Spectrometer: Components of Tandem Mass Spectrometer 11-Apr-12 Solairajan 102 MS-1 Collision cell MS-2Applications of Tandem MS: Applications of Tandem MS Biotechnology & Pharmaceutical To determine chemical structure of drugs and drug metabolites. Detection/quantification of impurities, drugs and their metabolites in biological fluids and tissues . Analysis of liquid mixtures Fingerprinting Nutraceuticals /herbal drugs/tracing source of natural products or drugs Clinical testing & Toxicology Inborn errors of metabolism, cancer, diabetes, various poisons, drugs of abuse, etc. 11-Apr-12 Solairajan 103MALDI-MS: MALDI-MS Matrix-assisted laser desorption/ionization (MALDI) is a soft ionization technique used in mass spectrometry allowing the analysis of biomolecules ( biopolymers such as DNA, proteins, peptides and sugars ) and large organic molecules (such as polymers, dendrimers and other macromolecules ). 11-Apr-12 Solairajan 104PowerPoint Presentation: MALDI is based on the bombardment of sample molecules with a laser light to bring about sample ionisation . The sample is pre-mixed with a highly absorbing matrix compound for the most consistent and reliable results. The matrix transforms the laser energy into excitation energy for the sample, which leads to sputtering of analyte and matrix ions from the surface of the mixture. Most commercially available MALDI mass spectrometers now have a pulsed nitrogen laser of wavelength 337 nm. 11-Apr-12 Solairajan 105Common matrix in MALDI: Common matrix in MALDI 11-Apr-12 Solairajan 106 Matrix Solvent Applications 2,5-dihydroxy benzoic acid Acetonitrile,water,methanol,acetone,CHcl 3 Peptides,Nucleotides , oligo nucleotides 3,5-dimethoxy-4-hydroxycinnamic acid Acetonitrile , water,acetone , CHcl 3 Peptides,proteins,lipids 4-hydroxy-3-methoxycinnamic acid Acetonitrile, water, propanol Proteins Picolinic acid Ethanol Oligo nucleotidesPowerPoint Presentation: 11-Apr-12 Solairajan 107PowerPoint Presentation: 11-Apr-12 Solairajan 108Applications of MS:-: Applications of MS:- Elucidation of the structure of the organic and biological molecules. Determination of molecular mass of peptides, proteins, and Oligonucleotides. Monitoring gases in patients breath during surgery. Identification of drugs abuse and metabolites of drugs of abuse in blood, urine, and saliva. Analyses of aerosol particles. Determination of pesticides residues in food . 11-Apr-12 Solairajan 109References:-: References:- Instrumental methods of chemical analysis by willard Organic spectroscopy by William kemp Spectroscopic identification of organic compounds by Silverstein Instrumental analysis by skoog Wikipedia ww2.chemistry.gatech.edu/class/4341-6371/ fahrni /set02.pdf 11-Apr-12 Solairajan 110PowerPoint Presentation: By A.Solairajan 11-Apr-12 Solairajan 111 You do not have the permission to view this presentation. In order to view it, please contact the author of the presentation.