Mass spectrometry is an analytical technique that can be used to deduce the molecular formula of an unknown compound. It works by bombarding gaseous molecules with electrons, which knocks out electrons to create molecular ions. The masses and abundances of these ions are measured to form a mass spectrum that acts as a molecular fingerprint. This spectrum can be analyzed to determine the compound's molecular formula. Fragmentation of the molecular ion during mass spectrometry gives additional structural information. Infrared spectroscopy and NMR spectroscopy provide complementary structural information by analyzing the vibrations and magnetic properties of molecules' bonds and nuclei. Chromatography techniques separate mixtures and can be coupled with mass spectrometry for analysis.
more chemistry contents are available
1. pdf file on Termmate: https://www.termmate.com/rabia.aziz
2. YouTube: https://www.youtube.com/channel/UCKxWnNdskGHnZFS0h1QRTEA
3. Facebook: https://web.facebook.com/Chemist.Rabia.Aziz/
4. Blogger: https://chemistry-academy.blogspot.com/
Physical Chemistry
Nmr spectroscopy:- An overview and its principleSMGJAFAR
NMR spectroscopy is a technique that uses radio waves to analyze atomic nuclei and determine molecular structures. It is based on detecting radio signal absorption by atomic nuclei within a magnetic field. 1H and 13C NMR are common types. The history and principles of NMR are described, including how nuclei with spin absorb electromagnetic radiation and how chemical shifts, splitting, and intensity of signals provide structural information. Applications include identifying molecular structures, purity, and composition in fields like forensics, medicine, and materials analysis. Forensic uses include analyzing trace evidence, controlled substances, and toxins.
The earliest voltammetric technique
Heyrovsky invented the original polarographic method in 1922, conventional direct current polarography (DCP).
It employs a dropping mercury electrode (DME) to continuously renew the electrode surface.
Diffusion is the mechanism of mass transport.
When an external potential is applied to a cell
containing a reducing substance such as CdCl2,
The following reaction will occur:
Cd2+ + 2e + Hg = Cd(Hg)
The technique depends on increasing the applied
voltage at a steady rate and simultaneously
record photographically the current-voltage
curve (polarogram)
The apparatus used is called a polarograph .
When an external potential is applied to a cell
containing a reducing substance such as CdCl2,
The following reaction will occur:
Cd2+ + 2e + Hg = Cd(Hg)
The technique depends on increasing the applied
voltage at a steady rate and simultaneously
record photographically the current-voltage
curve (polarogram)
The apparatus used is called a polarograph .
Capillary tube about 10-15cm
Int. diameter of 0.05mm
A vertical distance being maintained betwwen DME and the solution
Drop time of 1-5 seconds
Drop diameter 0.5mm
The supporting electrolyte
is a solution of (KNO3, NaCl, Na3PO4) in which the sample (which must be electroactive) is dissolved.
Function of the supporting electrolyte
It raises the conductivity of the solution.
It carries the bulk of the current so prevent the
migration of electroactive materials to working
electrode.
It may control pH
It may associate with the electroactive solute as
in the complexing of the metal ions by ligands.
Conductometry involves measuring the electrical conductivity of a solution. It works by applying a potential difference between electrodes in a solution, causing ion migration and electrical conductivity. Conductance is inversely proportional to resistance. Conductometric titrations monitor conductivity changes during titrations to identify the equivalence point. Advantages include simplicity, not requiring indicators, and suitability for turbid or colored solutions. Applications include water purity testing, pharmaceutical analysis, and determining salinity.
Infrared (IR) spectroscopy involves using IR radiation to analyze chemical bonds and molecular structures. The IR spectrum provides information on the types of chemical bonds and functional groups present in a compound. Most commonly, IR spectroscopy measures the absorption of IR radiation by a sample, though emission and reflection can also be used. The technique is widely applied to analyze organic materials, as well as some inorganic and organometallic compounds.
Polarography is an electroanalytical technique that uses a dropping mercury electrode to determine the concentration and nature of substances in a solution. It involves measuring the current between two electrodes - a polarized indicator electrode made of mercury, and a non-polarized reference electrode - as the voltage is gradually increased. The current readings form a polarogram curve that can identify substances based on their half-wave potential and determine concentrations from the limiting diffusion current. Polarography finds applications in fields like water quality testing, medicine, and electrochemistry.
It contains what is amperometry and where it will be derived and what is the principle behind the amperometry. Instrumentation of amperometry and the purpose of dipping mercury electrode and rotating platinum electrode. The advantage over rotating platinum electrodes. Amperometric titration curves for reducible ions and non-reducible ions. What tells the Ilkovic equation and how it relates to the amperometry is also included. Applications, advantages, and disadvantages of amperometric titration are also included. Questions related to amperometry and amperometric titration are given for practice. The contents taken from the websites are also given.
more chemistry contents are available
1. pdf file on Termmate: https://www.termmate.com/rabia.aziz
2. YouTube: https://www.youtube.com/channel/UCKxWnNdskGHnZFS0h1QRTEA
3. Facebook: https://web.facebook.com/Chemist.Rabia.Aziz/
4. Blogger: https://chemistry-academy.blogspot.com/
Physical Chemistry
Nmr spectroscopy:- An overview and its principleSMGJAFAR
NMR spectroscopy is a technique that uses radio waves to analyze atomic nuclei and determine molecular structures. It is based on detecting radio signal absorption by atomic nuclei within a magnetic field. 1H and 13C NMR are common types. The history and principles of NMR are described, including how nuclei with spin absorb electromagnetic radiation and how chemical shifts, splitting, and intensity of signals provide structural information. Applications include identifying molecular structures, purity, and composition in fields like forensics, medicine, and materials analysis. Forensic uses include analyzing trace evidence, controlled substances, and toxins.
The earliest voltammetric technique
Heyrovsky invented the original polarographic method in 1922, conventional direct current polarography (DCP).
It employs a dropping mercury electrode (DME) to continuously renew the electrode surface.
Diffusion is the mechanism of mass transport.
When an external potential is applied to a cell
containing a reducing substance such as CdCl2,
The following reaction will occur:
Cd2+ + 2e + Hg = Cd(Hg)
The technique depends on increasing the applied
voltage at a steady rate and simultaneously
record photographically the current-voltage
curve (polarogram)
The apparatus used is called a polarograph .
When an external potential is applied to a cell
containing a reducing substance such as CdCl2,
The following reaction will occur:
Cd2+ + 2e + Hg = Cd(Hg)
The technique depends on increasing the applied
voltage at a steady rate and simultaneously
record photographically the current-voltage
curve (polarogram)
The apparatus used is called a polarograph .
Capillary tube about 10-15cm
Int. diameter of 0.05mm
A vertical distance being maintained betwwen DME and the solution
Drop time of 1-5 seconds
Drop diameter 0.5mm
The supporting electrolyte
is a solution of (KNO3, NaCl, Na3PO4) in which the sample (which must be electroactive) is dissolved.
Function of the supporting electrolyte
It raises the conductivity of the solution.
It carries the bulk of the current so prevent the
migration of electroactive materials to working
electrode.
It may control pH
It may associate with the electroactive solute as
in the complexing of the metal ions by ligands.
Conductometry involves measuring the electrical conductivity of a solution. It works by applying a potential difference between electrodes in a solution, causing ion migration and electrical conductivity. Conductance is inversely proportional to resistance. Conductometric titrations monitor conductivity changes during titrations to identify the equivalence point. Advantages include simplicity, not requiring indicators, and suitability for turbid or colored solutions. Applications include water purity testing, pharmaceutical analysis, and determining salinity.
Infrared (IR) spectroscopy involves using IR radiation to analyze chemical bonds and molecular structures. The IR spectrum provides information on the types of chemical bonds and functional groups present in a compound. Most commonly, IR spectroscopy measures the absorption of IR radiation by a sample, though emission and reflection can also be used. The technique is widely applied to analyze organic materials, as well as some inorganic and organometallic compounds.
Polarography is an electroanalytical technique that uses a dropping mercury electrode to determine the concentration and nature of substances in a solution. It involves measuring the current between two electrodes - a polarized indicator electrode made of mercury, and a non-polarized reference electrode - as the voltage is gradually increased. The current readings form a polarogram curve that can identify substances based on their half-wave potential and determine concentrations from the limiting diffusion current. Polarography finds applications in fields like water quality testing, medicine, and electrochemistry.
It contains what is amperometry and where it will be derived and what is the principle behind the amperometry. Instrumentation of amperometry and the purpose of dipping mercury electrode and rotating platinum electrode. The advantage over rotating platinum electrodes. Amperometric titration curves for reducible ions and non-reducible ions. What tells the Ilkovic equation and how it relates to the amperometry is also included. Applications, advantages, and disadvantages of amperometric titration are also included. Questions related to amperometry and amperometric titration are given for practice. The contents taken from the websites are also given.
This document provides an overview of infrared (IR) spectroscopy. It discusses the IR region of the electromagnetic spectrum, the basic principles of IR spectroscopy, and factors that influence molecular vibrations. Requirements for IR absorption include an electric dipole moment and the radiation wavelength matching the natural vibration frequency. Molecular vibrations observed in IR spectroscopy include stretches, bends, and rotations. Instrumentation components like IR sources, wavelength selectors, detectors, and sample handling techniques are also outlined. Finally, applications of IR spectroscopy like structure elucidation and identification of functional groups are mentioned.
1 introduciton to analytical chemistry1Uday Deokate
Analytical chemistry is defined as the science of determining the qualitative and quantitative composition of matter. It involves both qualitative analysis to identify analytes and quantitative analysis to determine exact amounts or concentrations. Classical wet chemical methods include precipitation, extraction, and titrimetric measurements, while instrumental methods use analytical instrumentation to measure properties like light absorption, mass, and fluorescence. Analytical chemistry has important applications in fields like clinical analysis, pharmaceutical analysis, environmental analysis, and forensic analysis. It is used to characterize materials, determine complexity and composition of species, and provide numerical information about analytes.
Mass spectrometry is a technique that ionizes chemical compounds and separates and identifies ions based on their mass-to-charge ratios. It can provide both qualitative and quantitative information about molecular structures. During analysis, molecules are bombarded by electrons which produces molecular ions and fragment ions. These ions are then separated by their mass in electric and magnetic fields. By analyzing the masses of molecular and fragment ions, mass spectrometry can determine molecular formulas and elucidate molecular structures. It is a highly sensitive technique that is widely used for molecular identification.
This document provides information on potentiometry and potentiometric titration. It discusses the basic principles of potentiometry including electrode potentials and how a potential difference is established between an electrode and solution. It describes the instrumentation used including reference electrodes like calomel and silver-silver chloride electrodes and indicator electrodes like metal, glass membrane, and quinhydrone electrodes. It also discusses different types of potentiometric titrations and provides examples of applications for potentiometry in various industries.
This document provides an overview of C-13 NMR spectroscopy. It discusses the history and principle of NMR spectroscopy, focusing on C-13. Key points include: C-13 has a nuclear spin of 1/2, allowing it to be detected by NMR, unlike C-12. The chemical shift range for C-13 is much broader than for proton NMR, from 0-220 ppm. The number of C-13 signals indicates the number of non-equivalent carbon types in a molecule. C-13 coupling is observed with directly bonded protons and other nearby nuclei. Applications of C-13 NMR include structure elucidation of organic and biochemical compounds.
Analytical chemistry involves separating, identifying, and quantifying the components of materials. Historically, analytical chemistry developed qualitative and quantitative analysis methods using classical techniques like chemical tests and titrations. Modern instrumental methods include spectroscopy, mass spectrometry, electrochemical analysis, thermal analysis, separation techniques, and microscopy. Hyphenated techniques combine two or more analytical methods, such as gas chromatography-mass spectrometry, to detect and separate chemicals.
This document discusses overtones and Fermi resonance in infrared spectroscopy. It defines overtones as absorptions that occur at integral multiples of the fundamental frequency, such as a band at 1000 cm-1 accompanying a fundamental at 500 cm-1. Fermi resonance occurs when a fundamental and overtone band have similar energies, causing them to interact and shift in intensity and frequency. This can result in a "Fermi doublet" with one band increasing while the other decreases in energy. The document provides examples of overtones and Fermi resonance in infrared spectra.
The document summarizes infrared (IR) spectroscopy, including its principle, instrumentation, applications, and interpretation of spectra. IR spectroscopy works by detecting the vibrational and rotational absorption frequencies of molecules when exposed to IR radiation. The spectrum produced provides information on molecular structure and bonding. Key regions of the IR spectrum correspond to common functional groups like C=O, N-H, and O-H. Analysis of peak positions and relative intensities allows identification of compounds and detection of impurities.
Potentiometry is an analytical technique that measures the potential of electrochemical cells without drawing current. It involves using a reference electrode with a known potential and an indicator electrode whose potential varies with analyte concentration. The cell potential is measured and related to concentration using the Nernst equation. Common reference electrodes include the standard hydrogen electrode and saturated calomel electrode. Glass membrane and ion-selective electrodes are often used as indicator electrodes to detect specific ions like hydrogen or fluoride ions. Potentiometry finds applications in clinical analysis, environmental monitoring, and titration experiments.
Flame photometry uses the principle that metal ions emit light of characteristic wavelengths when excited by a flame. The intensity of light emitted is proportional to the concentration of metal ions. In flame photometry, the sample solution is nebulized and atomized in a flame, causing the metal ions to emit light. A filter selects the characteristic wavelength, which is detected and its intensity measured, allowing determination of the metal ion concentration. Flame photometry is used to analyze samples for concentrations of ions such as sodium, potassium, lithium, and calcium.
This document discusses the principles and procedures of conductometric analysis. Conductometric analysis measures the electrical conductivity of a solution due to ion mobility. The conductivity is affected by factors like number, charge, size of ions, and temperature. It involves titrating a solution containing ions and measuring the change in conductivity. This allows determination of the endpoint of the titration from the plotted conductivity-volume curve. The document defines key terms, describes instrumentation including conductivity cells and electrodes, and discusses different types of conductometric titrations like acid-base, redox, and complexometric titrations. Conductometric titrations provide accurate results for analyses without requiring indicators.
Atomic absorption spectroscopy is a common technique for detecting metals and metalloids in samples. It works by vaporizing the sample into free atoms that can absorb light at specific wavelengths. The instrument works by using a light source, atomizer, monochromator, and detector. Samples are vaporized in a flame or graphite furnace and the amount of light absorbed is measured to determine concentration. It can analyze over 60 elements with high selectivity and is used for applications like water analysis and determining metal levels in biological samples.
UV-Visible Spectroscopy is a technique that uses light in the visible and adjacent ranges. It works based on how molecules absorb light at specific wavelengths. The document discusses the principles of UV-Vis spectroscopy including Beer's law, electronic transitions, chromophores and auxochromes. It also covers instrumentation components like light sources, monochromators, sample cells and detectors. Factors affecting absorption spectra are solvents, pH and conjugation. The technique has applications in analytical chemistry for identification and quantification of analytes.
Neutron activation analysis is a nuclear analytical technique where samples are bombarded with neutrons, inducing radioactivity. It was discovered in 1936 and allows determination of elemental concentrations. The sample is irradiated, inducing radioisotopes that emit detectable gamma rays. It has high sensitivity and precision, requires small samples, and is nondestructive, but has detection limits and potential interferences from matrix effects.
Complexometric TITRATION FOR PG IST SEM prakash64742
This document discusses complexometric titration, which involves titrating a metal ion with a complexing agent or chelating agent. It provides examples of different types of complexometric titrations including direct titration, back titration, and replacement titration. Assays for several substances using complexometric titration methods are described, such as magnesium sulfate using EDTA as the titrant, and calcium carbonate where the carbonate is dissolved using acid prior to titration.
C13 NMR spectroscopy provides information about carbon atoms in molecules. It works based on the absorption of radio waves by carbon-13 nuclei in a magnetic field. There are a few key points:
1) C13 NMR is difficult to analyze due to the low natural abundance of C13 and its weaker magnetic resonance compared to protons.
2) Different types of carbon atoms (CH, CH2, CH3) can be distinguished based on their chemical shifts and coupling patterns. Proton decoupling is used to simplify spectra.
3) DEPT experiments analyze carbon types by enhancing signals from different hybridized carbons (CH, CH2, CH3) in different ways. This allows determining the number and type
Raman spectroscopy is a technique that uses lasers to study vibrational, rotational, and other low-frequency modes in a system. When light interacts with molecules, the light may be scattered at different wavelengths than the incident laser. This shift in wavelength provides information about molecular structure and symmetry. Raman spectroscopy can be used to examine inorganic, organic, and polymeric materials, determine molecular structure and interactions, and study chemical reactions and physical transformations.
This document discusses 13C NMR spectroscopy. It explains that 13C NMR can be used to determine the number of non-equivalent carbon atoms in a compound and identify carbon types like carbonyl, methylene, aromatic. The chemical shifts of carbonyl, nitrile and oxime carbons are spread over a wide range from 0-240 ppm. 13C NMR spectroscopy has applications in structure elucidation, detection of functional groups, identification of structural isomers, and metabolic studies. It is useful as a complementary technique to 1H NMR spectroscopy.
The document is about acids and alkalis and their reactions. It discusses how acids and alkalis react to form salts and water through a neutralization reaction. It provides examples of reactions between acids and bases like metals, metal oxides, and carbonates. The document also covers acid rain, how it is formed from air pollution, and its environmental effects. It describes methods to reduce acid rain by limiting the emissions of sulfur dioxide and nitrogen oxides.
ANALYTICAL TECHNIQUES (CHROMATOGRAPHY, SPECTROSCOPY, ELECTROPHOROSIS) IN PHAR...imran khan
This document reviews various analytical techniques used in pharmaceutical analysis, including chromatography, spectroscopy, and electrophoresis. It provides details on techniques such as thin layer chromatography, high-performance liquid chromatography, mass spectrometry, infrared spectroscopy, nuclear magnetic resonance spectroscopy, and discusses how these techniques are coupled with chromatography. The review highlights that analytical techniques play an important role in drug development and quality control, from understanding drug stability to quantifying impurities and ensuring proper drug content in marketed products.
This document provides an overview of infrared (IR) spectroscopy. It discusses the IR region of the electromagnetic spectrum, the basic principles of IR spectroscopy, and factors that influence molecular vibrations. Requirements for IR absorption include an electric dipole moment and the radiation wavelength matching the natural vibration frequency. Molecular vibrations observed in IR spectroscopy include stretches, bends, and rotations. Instrumentation components like IR sources, wavelength selectors, detectors, and sample handling techniques are also outlined. Finally, applications of IR spectroscopy like structure elucidation and identification of functional groups are mentioned.
1 introduciton to analytical chemistry1Uday Deokate
Analytical chemistry is defined as the science of determining the qualitative and quantitative composition of matter. It involves both qualitative analysis to identify analytes and quantitative analysis to determine exact amounts or concentrations. Classical wet chemical methods include precipitation, extraction, and titrimetric measurements, while instrumental methods use analytical instrumentation to measure properties like light absorption, mass, and fluorescence. Analytical chemistry has important applications in fields like clinical analysis, pharmaceutical analysis, environmental analysis, and forensic analysis. It is used to characterize materials, determine complexity and composition of species, and provide numerical information about analytes.
Mass spectrometry is a technique that ionizes chemical compounds and separates and identifies ions based on their mass-to-charge ratios. It can provide both qualitative and quantitative information about molecular structures. During analysis, molecules are bombarded by electrons which produces molecular ions and fragment ions. These ions are then separated by their mass in electric and magnetic fields. By analyzing the masses of molecular and fragment ions, mass spectrometry can determine molecular formulas and elucidate molecular structures. It is a highly sensitive technique that is widely used for molecular identification.
This document provides information on potentiometry and potentiometric titration. It discusses the basic principles of potentiometry including electrode potentials and how a potential difference is established between an electrode and solution. It describes the instrumentation used including reference electrodes like calomel and silver-silver chloride electrodes and indicator electrodes like metal, glass membrane, and quinhydrone electrodes. It also discusses different types of potentiometric titrations and provides examples of applications for potentiometry in various industries.
This document provides an overview of C-13 NMR spectroscopy. It discusses the history and principle of NMR spectroscopy, focusing on C-13. Key points include: C-13 has a nuclear spin of 1/2, allowing it to be detected by NMR, unlike C-12. The chemical shift range for C-13 is much broader than for proton NMR, from 0-220 ppm. The number of C-13 signals indicates the number of non-equivalent carbon types in a molecule. C-13 coupling is observed with directly bonded protons and other nearby nuclei. Applications of C-13 NMR include structure elucidation of organic and biochemical compounds.
Analytical chemistry involves separating, identifying, and quantifying the components of materials. Historically, analytical chemistry developed qualitative and quantitative analysis methods using classical techniques like chemical tests and titrations. Modern instrumental methods include spectroscopy, mass spectrometry, electrochemical analysis, thermal analysis, separation techniques, and microscopy. Hyphenated techniques combine two or more analytical methods, such as gas chromatography-mass spectrometry, to detect and separate chemicals.
This document discusses overtones and Fermi resonance in infrared spectroscopy. It defines overtones as absorptions that occur at integral multiples of the fundamental frequency, such as a band at 1000 cm-1 accompanying a fundamental at 500 cm-1. Fermi resonance occurs when a fundamental and overtone band have similar energies, causing them to interact and shift in intensity and frequency. This can result in a "Fermi doublet" with one band increasing while the other decreases in energy. The document provides examples of overtones and Fermi resonance in infrared spectra.
The document summarizes infrared (IR) spectroscopy, including its principle, instrumentation, applications, and interpretation of spectra. IR spectroscopy works by detecting the vibrational and rotational absorption frequencies of molecules when exposed to IR radiation. The spectrum produced provides information on molecular structure and bonding. Key regions of the IR spectrum correspond to common functional groups like C=O, N-H, and O-H. Analysis of peak positions and relative intensities allows identification of compounds and detection of impurities.
Potentiometry is an analytical technique that measures the potential of electrochemical cells without drawing current. It involves using a reference electrode with a known potential and an indicator electrode whose potential varies with analyte concentration. The cell potential is measured and related to concentration using the Nernst equation. Common reference electrodes include the standard hydrogen electrode and saturated calomel electrode. Glass membrane and ion-selective electrodes are often used as indicator electrodes to detect specific ions like hydrogen or fluoride ions. Potentiometry finds applications in clinical analysis, environmental monitoring, and titration experiments.
Flame photometry uses the principle that metal ions emit light of characteristic wavelengths when excited by a flame. The intensity of light emitted is proportional to the concentration of metal ions. In flame photometry, the sample solution is nebulized and atomized in a flame, causing the metal ions to emit light. A filter selects the characteristic wavelength, which is detected and its intensity measured, allowing determination of the metal ion concentration. Flame photometry is used to analyze samples for concentrations of ions such as sodium, potassium, lithium, and calcium.
This document discusses the principles and procedures of conductometric analysis. Conductometric analysis measures the electrical conductivity of a solution due to ion mobility. The conductivity is affected by factors like number, charge, size of ions, and temperature. It involves titrating a solution containing ions and measuring the change in conductivity. This allows determination of the endpoint of the titration from the plotted conductivity-volume curve. The document defines key terms, describes instrumentation including conductivity cells and electrodes, and discusses different types of conductometric titrations like acid-base, redox, and complexometric titrations. Conductometric titrations provide accurate results for analyses without requiring indicators.
Atomic absorption spectroscopy is a common technique for detecting metals and metalloids in samples. It works by vaporizing the sample into free atoms that can absorb light at specific wavelengths. The instrument works by using a light source, atomizer, monochromator, and detector. Samples are vaporized in a flame or graphite furnace and the amount of light absorbed is measured to determine concentration. It can analyze over 60 elements with high selectivity and is used for applications like water analysis and determining metal levels in biological samples.
UV-Visible Spectroscopy is a technique that uses light in the visible and adjacent ranges. It works based on how molecules absorb light at specific wavelengths. The document discusses the principles of UV-Vis spectroscopy including Beer's law, electronic transitions, chromophores and auxochromes. It also covers instrumentation components like light sources, monochromators, sample cells and detectors. Factors affecting absorption spectra are solvents, pH and conjugation. The technique has applications in analytical chemistry for identification and quantification of analytes.
Neutron activation analysis is a nuclear analytical technique where samples are bombarded with neutrons, inducing radioactivity. It was discovered in 1936 and allows determination of elemental concentrations. The sample is irradiated, inducing radioisotopes that emit detectable gamma rays. It has high sensitivity and precision, requires small samples, and is nondestructive, but has detection limits and potential interferences from matrix effects.
Complexometric TITRATION FOR PG IST SEM prakash64742
This document discusses complexometric titration, which involves titrating a metal ion with a complexing agent or chelating agent. It provides examples of different types of complexometric titrations including direct titration, back titration, and replacement titration. Assays for several substances using complexometric titration methods are described, such as magnesium sulfate using EDTA as the titrant, and calcium carbonate where the carbonate is dissolved using acid prior to titration.
C13 NMR spectroscopy provides information about carbon atoms in molecules. It works based on the absorption of radio waves by carbon-13 nuclei in a magnetic field. There are a few key points:
1) C13 NMR is difficult to analyze due to the low natural abundance of C13 and its weaker magnetic resonance compared to protons.
2) Different types of carbon atoms (CH, CH2, CH3) can be distinguished based on their chemical shifts and coupling patterns. Proton decoupling is used to simplify spectra.
3) DEPT experiments analyze carbon types by enhancing signals from different hybridized carbons (CH, CH2, CH3) in different ways. This allows determining the number and type
Raman spectroscopy is a technique that uses lasers to study vibrational, rotational, and other low-frequency modes in a system. When light interacts with molecules, the light may be scattered at different wavelengths than the incident laser. This shift in wavelength provides information about molecular structure and symmetry. Raman spectroscopy can be used to examine inorganic, organic, and polymeric materials, determine molecular structure and interactions, and study chemical reactions and physical transformations.
This document discusses 13C NMR spectroscopy. It explains that 13C NMR can be used to determine the number of non-equivalent carbon atoms in a compound and identify carbon types like carbonyl, methylene, aromatic. The chemical shifts of carbonyl, nitrile and oxime carbons are spread over a wide range from 0-240 ppm. 13C NMR spectroscopy has applications in structure elucidation, detection of functional groups, identification of structural isomers, and metabolic studies. It is useful as a complementary technique to 1H NMR spectroscopy.
The document is about acids and alkalis and their reactions. It discusses how acids and alkalis react to form salts and water through a neutralization reaction. It provides examples of reactions between acids and bases like metals, metal oxides, and carbonates. The document also covers acid rain, how it is formed from air pollution, and its environmental effects. It describes methods to reduce acid rain by limiting the emissions of sulfur dioxide and nitrogen oxides.
ANALYTICAL TECHNIQUES (CHROMATOGRAPHY, SPECTROSCOPY, ELECTROPHOROSIS) IN PHAR...imran khan
This document reviews various analytical techniques used in pharmaceutical analysis, including chromatography, spectroscopy, and electrophoresis. It provides details on techniques such as thin layer chromatography, high-performance liquid chromatography, mass spectrometry, infrared spectroscopy, nuclear magnetic resonance spectroscopy, and discusses how these techniques are coupled with chromatography. The review highlights that analytical techniques play an important role in drug development and quality control, from understanding drug stability to quantifying impurities and ensuring proper drug content in marketed products.
Chromatography is a technique used to separate mixtures into individual components by passing them through a stationary phase. It involves using different methods like liquid chromatography, thin-layer chromatography, gas chromatography, and paper chromatography to separate compounds in inks, dyes, plant pigments, chemicals, and other unknown substances. Chromatography can identify unknown plant pigments, determine the chemical composition of substances, and separate components in mixtures like gasoline.
Chromatography is a technique used to separate and identify the components of a mixture. It works by allowing molecules to distribute themselves between a stationary and mobile phase, so that molecules that interact more with the mobile phase move faster. Chromatographic techniques can be classified based on the interaction with the stationary phase or physical state of the mobile phase. Key techniques include adsorption, partition, ion exchange, exclusion, gas, liquid, and thin layer chromatography. Proper sample preparation and development conditions are important for achieving optimal separation and resolution of components in the mixture.
Chromatography is an analytical technique used to separate, identify, and quantify components in complex mixtures. It works based on the differential partitioning of molecules between a stationary and mobile phase. The document defines key terms related to chromatography like stationary phase, mobile phase, eluent, eluate, elution, chromatogram, and flow rate. It also describes different types of chromatography like liquid chromatography, gas chromatography, and high pressure liquid chromatography. The document provides details on different modes of chromatography like adsorption, partition, ion exchange, size exclusion, and affinity chromatography. It discusses enzyme purification steps and parameters for anion exchange and hydrophobic interaction chromatography columns. Key properties and suggested buffers for DEAE Sepharose Fast Flow column are also presented
Column chromatography is a separation technique that uses a column packed with a stationary phase. As a mixture passes through the column via a mobile phase, components separate based on how they partition between the stationary and mobile phases. Key factors that affect separation are the types of stationary and mobile phases used, as well as column characteristics like length and diameter. Common stationary phases include silica, alumina, and cellulose while mobile phases are selected based on solvent polarity and component solubility. Proper packing of the stationary phase into the column is also important for achieving efficient separation.
The document discusses various forensic science disciplines and techniques used in criminal investigations. It describes chemistry techniques like chemiluminescent substrates and latent print identification. Biology techniques covered include forensic autopsies, blood testing, and biological fingerprinting. Physics techniques analyzed ballistic fingerprinting, ballistic microstamping, and firearm identification. The document also provides examples of how these techniques have been applied to investigations like the assassination of Benazir Bhutto.
Desalination of Sea Water using Membrane technologyChandni Sinha
The document discusses various desalination methods for obtaining fresh water from seawater. It begins by introducing the importance of desalination given increasing fresh water scarcity. There are two main types of desalination processes: thermal and membrane. Thermal processes involve boiling saline water to produce distilled water, while membrane processes use semi-permeable membranes to separate fresh water from salt water. The document then goes into detail about various thermal and membrane desalination methods, including multi-stage flash distillation, reverse osmosis, and nanofiltration. It also discusses factors involved in membrane development and selection.
Analytical chemistry involves separating, identifying, and quantifying components of matter. Hyphenated techniques combine two analytical methods, such as gas chromatography coupled with mass spectrometry (GC-MS). GC-MS separates chemical mixtures using gas chromatography and then identifies components using mass spectrometry. Other common hyphenated techniques include liquid chromatography-mass spectrometry (LC-MS) and gas chromatography-infrared spectroscopy (GC-IR). These coupled techniques provide enhanced sensitivity and accuracy for analyzing organic compounds, pollutants, drugs, proteins, and more.
Screening models for central and peripheral analgesicskrishnabajgire
This document describes screening models used to test central and peripheral analgesic activity. For central analgesic activity, it discusses the hot plate test, grid-shock test, and tail immersion test which measure response latency to a painful stimulus. For peripheral analgesic activity, it discusses the writhing test which counts stretching behaviors in mice after an irritant injection, and the Randall-Selitto test which applies pressure to inflamed tissue in rats to measure pain threshold changes.
This document discusses column chromatography, which separates components of a mixture through continuous distribution between a stationary and mobile phase. It describes the basic principles, types (adsorption, partition, ion exchange, gel), components (stationary phase, mobile phase, sample), and process (elution). Column chromatography is useful for purifying compounds and isolating metabolites. It allows separation of various mixtures but requires more solvent and time than other techniques.
Ayurveda is a traditional system of medicine native to India that is based on balancing the three doshas (bodily humors) of vata, pitta, and kapha. The earliest Ayurvedic texts date back to 1500 BC and are found in Hindu scriptures like the Atharvaveda and Suśruta Saṃhitā. Ayurveda views health as a balance of physical, mental and emotional well-being. Diagnosis evaluates the doshas, and treatments emphasize herbal medicines, yoga, and lifestyle. The goal is to ensure proper functioning of the body's channels to prevent disease.
Mass spectrometry(Ionization Techniques) by Ashutosh PankeAshutosh Panke
The document discusses various ionization techniques used in mass spectrometry. It describes several gas phase ionization methods including electron impact ionization, chemical ionization, and field ionization. It also discusses several desorption ionization techniques, notably fast atom bombardment, matrix assisted laser desorption/ionization, electrospray ionization, and surface enhanced laser desorption/ionization. The document provides details on the mechanisms and applications of these various ionization methods. It also categorizes mass analyzers and discusses time-of-flight mass analyzers.
Mass Spectrometry Applications and spectral interpretation: BasicsShreekant Deshpande
Mass spectrometry is a powerful analytical tool that is extensively used in fields like biotechnology, pharmaceuticals, clinical research, and environmental analysis. It works by ionizing molecule samples and then separating the ions based on their mass-to-charge ratio, which provides information about molecular structure. This information can be used to identify unknown compounds, study reaction mechanisms, and more. Mass spectrometry requires only picomolar concentrations of samples and can detect small changes in molecular structure. It has various applications in medicinal chemistry, such as determining molecular weights, monitoring chemical reactions, elucidating unknown structures, and identifying drug mechanisms of action.
Applications of IR (Infrared) Spectroscopy in Pharmaceutical Industrywonderingsoul114
1. Infrared spectroscopy can be used to qualitatively and quantitatively analyze compounds. It is used to identify unknown substances by comparing their IR spectra to reference standards.
2. The "fingerprint" region from 1200-700 cm-1 is particularly useful for identification because small molecular differences result in significant spectral changes in this region. Computer search systems can also identify compounds by matching IR spectra to profiles of pure compounds.
3. IR spectroscopy allows determination of molecular structures by identifying the presence or absence of functional groups from their characteristic absorption bands. It can also be used to study the progress of chemical reactions.
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This ppt explains the basics of mass spectrometry and in application in pharmacognosy. Hope this helps you guys. Like, comment and save. If you hav problem downloading, send your email address; i'll post it for you by mail :)
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The rate theory of chromatography proposes equations to describe the processes that contribute to band broadening in chromatography. These include eddy diffusion, longitudinal diffusion, and resistance to mass transfer in both the mobile and stationary phases. The key equation from rate theory is the Van Deemter equation, which relates plate height to the average linear velocity of the mobile phase and factors A, B, and C that describe the various broadening processes. The Van Deemter equation can be used to determine the optimum mobile phase flow rate.
Halogenoalkanes are organic compounds where one or more hydrogen atoms in an alkane are replaced by halogen atoms such as fluorine, chlorine, bromine or iodine. Naming halogenoalkanes involves using prefixes to indicate the halogen atom and numerals to indicate the number and location of the halogen substitution. Halogenoalkanes can be classified as primary, secondary or tertiary depending on whether the carbon atom bonded to the halogen has one, two or three carbon substituents respectively.
This document provides an overview of various spectroscopy techniques used for structure determination, including NMR, IR, UV-Vis, and mass spectrometry. It discusses the basic principles of molecular spectroscopy and how each technique interacts with molecules to provide structural information. Key points covered include how electromagnetic radiation causes transitions between quantized energy levels, how different functional groups absorb at characteristic wavelengths/frequencies, and how mass spectrometry is used to determine molecular formula.
This document provides an overview of infrared spectroscopy, including:
- General uses such as identification of organic/inorganic compounds and determination of functional groups
- Common applications like identification of unknown compounds and reaction components
- Samples that can be analyzed as solids, liquids, or gases in small amounts
- Theory of infrared absorption involving molecular vibrations that change the dipole moment
The document summarizes a seminar presentation on UV-visible spectroscopy. It discusses the principles of UV-visible spectroscopy including electronic transitions, Beer's law, instrumentation involving radiation sources and detectors, and applications to analysis of organic compounds, simultaneous estimation of components in formulations, and use of derivative spectroscopy to resolve overlapping peaks. The presentation was given by Mr. Nitin P. Kanwale for a pharmacy program guided by Dr. D.V. Derle.
NMR spectroscopy is a technique used to determine the structure of organic molecules. It works by applying a strong magnetic field to atomic nuclei, causing them to absorb radio frequencies that are dependent on their chemical environment. This allows differentiation of chemically distinct hydrogen atoms. The frequency of absorption is measured in parts per million relative to a standard, and is influenced by factors like neighboring bonds, substituents, and spin-spin coupling between nuclei. NMR can be used to determine a compound's empirical formula, identify different types of protons, count the number of protons in each type, and elucidate relative stereochemistry and conformations.
This document discusses various analytical techniques including UV-visible spectroscopy, IR spectroscopy, colorimetry, flame photometry, and atomic absorption spectroscopy. It begins by introducing Beer-Lambert's law and its applications in quantitative analysis using spectrophotometry. It then provides details on the principles, instrumentation, and applications of UV-visible spectroscopy and IR spectroscopy. It describes how these techniques can be used to determine functional groups, identify organic compounds, and study molecular structure. The document also discusses the principles and applications of colorimetry in quantitative analysis of colored solutions.
The document provides an overview of several analytical techniques including spectroscopy, chromatography, and mass spectrometry. It describes the basic principles and components of infrared spectroscopy, how absorption spectra can be interpreted to identify functional groups. It also summarizes how chromatography separates mixtures based on differential affinity to a mobile and stationary phase, and how mass spectrometry analyzes molecules by detecting ionized molecular fragments.
This document summarizes a seminar on UV-visible spectroscopy presented by Mr. Nitin P. Kanwale. It discusses the basic principles of UV-visible spectroscopy including Beer's law and factors that affect absorption spectra. Instrumentation for UV-visible spectroscopy is described. Applications discussed include quantitative analysis of mixtures using derivative spectroscopy and simultaneous equations. The document concludes that derivative spectroscopy is a powerful tool for resolving overlapping signals in multi-component analyses.
Infrared spectroscopy analyzes the vibrational and rotational absorption bands of molecules within the infrared region of the electromagnetic spectrum. Different functional groups absorb infrared radiation at characteristic wavelengths that can be used for compound identification. Molecular vibrations occur when bonds stretch, bend, scissor, rock, wag, or twist, causing a change in dipole moment that allows absorption of infrared radiation.
This document provides information about infrared spectroscopy, including:
- It describes the basic components and operation of infrared spectrometers, including dispersive and Fourier transform instruments.
- Infrared spectroscopy is used to identify organic and inorganic compounds by detecting their characteristic absorption of infrared radiation.
- Samples require only small amounts in the range of micrograms to analyze solids and liquids, and as low as parts per billion for gases.
This document provides an introduction to NMR spectroscopy and its principles. It discusses the two main types of NMR - proton (1H NMR) and carbon-13 (13C NMR) spectroscopy. It covers the interpretation of 1H NMR spectra, including number of peaks, intensity of peaks, chemical shift, spin-spin splitting/multiplicity, and coupling constants. Interpretation of 13C NMR spectra is also discussed, including chemical shifts and spin-spin splitting. Examples of spectra are provided to illustrate these concepts. The document concludes that NMR spectroscopy is an effective tool for determining molecular structure.
This document provides an overview of solvents used in NMR spectroscopy and carbon-13 (13C) NMR. It discusses how 13C NMR is used to determine the number of non-equivalent carbons in a compound and identify carbon types. Key solvent properties for NMR are described, as are the characteristic features and interpretation of 13C NMR spectra. Applications of 13C NMR including structure elucidation and metabolic studies are highlighted. Fourier transform (FT) NMR instrumentation is briefly outlined, noting how it provides higher sensitivity than continuous wave NMR.
The document discusses various devices used for biomolecular and cellular research, focusing on those based on interactions with electromagnetic radiation. It describes spectrophotometers that use absorption, emission, or fluorescence of light to measure biomolecule concentrations or study structure. Specific devices covered include UV/visible absorption spectrophotometers, infrared spectrophotometers, Raman spectrometers, and circular dichroism instruments. These tools allow analyzing properties like protein secondary structure, drug interactions at the molecular level, and transport processes.
This document discusses infrared spectroscopy. It begins with definitions, explaining that infrared spectroscopy involves measuring the absorption of infrared light by a sample. It then covers the infrared spectroscopic process, theory of infrared absorption, examples of infrared spectra, and applications of infrared spectroscopy such as in chemistry, forensics, and testing pill quality. Advantages include being cheap and fast, while disadvantages include requiring sample preparation and being qualitative rather than quantitative. The conclusion restates that infrared spectroscopy identifies sample components by measuring their interaction with infrared radiation.
This document provides an overview of 13C and 2D NMR spectroscopy. It discusses key topics such as:
1) The basics of 13C NMR including that 13C has a natural abundance of 1.1% and each nonequivalent 13C gives a different signal. Hydrogen-decoupled 13C NMR is most common.
2) Principles of 2D NMR spectroscopy including how experiments have evolution, mixing, and detection periods to produce correlation maps between nuclear spins.
3) Specific 2D experiments like COSY which identifies proton-proton couplings and HECTOR which shows carbon-proton correlations are described. Applications of 13C and 2D NMR for structure elucidation and other
Introduction & Definition, Theory, instrumentation, Continuous – wave (CW) instrument, The pulsed Fourier Transform [FT] instrument, Solvents, Chemical shift
i. Shielding and de-shielding
ii. Factors affecting chemical shift
The document discusses the applications of infrared (IR) spectroscopy for qualitative and quantitative analysis. IR spectroscopy can be used to identify functional groups and determine molecular structures. It allows study of hydrogen bonding, geometrical isomers, and reaction progress. Near IR is applied to agriculture and pharmaceutical analysis while mid IR identifies organic and biological species. Far IR is used in medical treatments and astronomy. In summary, IR spectroscopy enables structural analysis and has various applications across chemistry, biology, medicine, and astronomy.
Lanthanide shift reagents are used in NMR spectroscopy to induce shifts in proton resonances. Europium complexes are commonly used shift reagents that cause downfield shifts, while cerium complexes cause upfield shifts. The amount of shift depends on the distance between the metal ion and protons, and the concentration of the shift reagent. Shift reagents simplify NMR spectra by resolving overlapping peaks and providing more detailed information about molecular structures. They are especially useful for distinguishing geometric isomers.
The document discusses 13C-NMR spectroscopy. It notes that while many of the theories of 1H-NMR also apply to 13C-NMR, there are several important differences. Specifically, 13C nuclei have a much weaker magnetic moment than protons, requiring more sample and signal averaging. Additionally, the range of chemical shifts is much wider for 13C than 1H, allowing each carbon to be distinguished. Modern techniques like DEPT and multidimensional NMR help overcome the challenges of analyzing 13C spectra.
বাংলাদেশের অর্থনৈতিক সমীক্ষা ২০২৪ [Bangladesh Economic Review 2024 Bangla.pdf] কম্পিউটার , ট্যাব ও স্মার্ট ফোন ভার্সন সহ সম্পূর্ণ বাংলা ই-বুক বা pdf বই " সুচিপত্র ...বুকমার্ক মেনু 🔖 ও হাইপার লিংক মেনু 📝👆 যুক্ত ..
আমাদের সবার জন্য খুব খুব গুরুত্বপূর্ণ একটি বই ..বিসিএস, ব্যাংক, ইউনিভার্সিটি ভর্তি ও যে কোন প্রতিযোগিতা মূলক পরীক্ষার জন্য এর খুব ইম্পরট্যান্ট একটি বিষয় ...তাছাড়া বাংলাদেশের সাম্প্রতিক যে কোন ডাটা বা তথ্য এই বইতে পাবেন ...
তাই একজন নাগরিক হিসাবে এই তথ্য গুলো আপনার জানা প্রয়োজন ...।
বিসিএস ও ব্যাংক এর লিখিত পরীক্ষা ...+এছাড়া মাধ্যমিক ও উচ্চমাধ্যমিকের স্টুডেন্টদের জন্য অনেক কাজে আসবে ...
A workshop hosted by the South African Journal of Science aimed at postgraduate students and early career researchers with little or no experience in writing and publishing journal articles.
A review of the growth of the Israel Genealogy Research Association Database Collection for the last 12 months. Our collection is now passed the 3 million mark and still growing. See which archives have contributed the most. See the different types of records we have, and which years have had records added. You can also see what we have for the future.
Strategies for Effective Upskilling is a presentation by Chinwendu Peace in a Your Skill Boost Masterclass organisation by the Excellence Foundation for South Sudan on 08th and 09th June 2024 from 1 PM to 3 PM on each day.
Assessment and Planning in Educational technology.pptxKavitha Krishnan
In an education system, it is understood that assessment is only for the students, but on the other hand, the Assessment of teachers is also an important aspect of the education system that ensures teachers are providing high-quality instruction to students. The assessment process can be used to provide feedback and support for professional development, to inform decisions about teacher retention or promotion, or to evaluate teacher effectiveness for accountability purposes.
it describes the bony anatomy including the femoral head , acetabulum, labrum . also discusses the capsule , ligaments . muscle that act on the hip joint and the range of motion are outlined. factors affecting hip joint stability and weight transmission through the joint are summarized.
Teacher notes
In ‘Slide Show’ mode, click the name of a section to jump straight to that slide.
Teacher notes
See Boardworks AS Chemistry ‘Atomic Structure’ for more information about how a mass spectrometer works.
Teacher notes
The molecular ion (M+) peak tells us the relative molecular mass (m) of the compound as at this peak charge (z) is one, so the mass-to-charge ratio, or m/z = m/1.
Photo credit: Simon Fraser / Science Photo Library
Researcher analysing results from a mass spectrometer experiment to determine the composition of a protein. Here the researcher is using the data generated to search protein databases for a match.
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In ‘Slide Show’ mode, click the name of a section to jump straight to that slide.
Teacher notes
See Boardworks AS Chemistry ‘Atomic Structure’ for more information about how infrared spectroscopy works.
Photo credit: Jim Varney / Science Photo Library
Policeman breathalyzing a motorist by his car at the side of a road. He is suspected of illegally driving under the influence of alcohol (drink-driving).
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Teacher notes
Tetramethylsilane (TMS) used to be added to samples before the NMR spectrum was recorded, which meant the compound used as the standard had to be unreactive so it did not react with the sample. It was also important the standard gave a sharp peak in both the 1H and 13C NMR spectra, and was cheap and nontoxic. As NMR is a non-destructive technique the sample can be recovered after analysis, so it was also important that the standard chemical could easily be removed, e.g. by evaporation.
Sometimes the peak due to TMS (at δ=0) is shown on NMR spectra, but often it is omitted.
Teacher notes
Nb the H in an OH group doesn’t undergo splitting.
Teacher notes
The splitting of the hydrogens shown in green is complex as they are split by both the hydrogens shown in blue and those in red, resulting in a quartet of doublets (8 peaks in total).
The chemical shift values of O–H and N–H protons can vary dramatically depending on conditions, and therefore can be hard to identify. O–H and N–H proton peaks can, however, be identified by the method of proton exchange using deuterium oxide (D2O). For example, the NMR spectrum for ethanol can first be measured in the usual way, and then re-measured with a few drops of D2O added to the solution. On the second spectrum the peak due to the O–H proton will have disappeared. This is because the D2O molecules interact with the alcohol group, causing it to be exchanged it for an O–D group, which has a different chemical shift value.
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In ‘Slide Show’ mode, click the name of a section to jump straight to that slide.
Photo credit: Jim Yost Photography / NREL
Liquid Chromatography Mass Spectrometry system
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Boardworks A2 Chemistry
Structure Determination
Teacher notes
adsorption – The adhesion of molecules to a surface. The molecules that attach are called adsorbate and the surface is the adsorbent. Adsorption is vital to chromatography.
chemical shift – A measure of the chemical environment of a particular nucleus within a molecule. Chemical shift values are quoted relative to a standard compound tetramethylsilane (TMS), and are measured in parts per million (ppm) of the strength of the magnetic field strength required for resonance in TMS.
chromatogram – The visible record of the separation of substances in mixtures by chromatography.
chromatography – A laboratory technique used to separate substances in a mixture. The mixture is dissolved in a mobile phase, which is then passed through a stationary phase. Substances are separated on the basis of their affinity with the stationary phase.
column chromatography – A form of chromatography in which the mixture to be separated is dissolved in a solvent. This is the eluent and is passed through a column containing a stationary phase (often aluminium oxide). The components of the mixture move at different rates through the column, and can be collected as they run out of the bottom.
eluent – The mobile phase in column chromatography. Consists of the mixture to be separated dissolved in a solvent.
fingerprint region – The region below 1500 cm-1 in an infrared spectrum, where there are many peaks which are difficult to assign. An exact match of the fingerprint region with a reference spectrum gives the identity of a compound.
fragmentation – A phenomenon whereby some ions disintegrate into smaller fragments during mass spectrometry, leading to multiple peaks in the resulting spectrum.
gas–liquid chromatography – A form of chromatography in which a mixture is injected into a coiled capillary tube inside an oven, where it vaporizes. An unreactive carrier gas (the mobile phase) transports the mixture through the coil, where the components interact with a powder lining the coil, which acts as the stationary phase. The components exit the coil at different times after injection and may pass straight into a mass spectrometer.
high performance liquid chromatography – A form of column chromatography in which the eluent moves through the column under high pressure. This results in a faster and more effective separation.
infrared spectroscopy – A technique that measures the absorption of different frequencies of infrared energy by a sample of a substance. This gives information about the types of functional group present in a compound.
infrared spectrum – A plot of transmission of infrared radiation against wavenumber (1 / wavelength).
integration – A mathematical technique for working out the area under the peak on a line graph. This is useful in proton NMR as the area under a peak in a 1H NMR spectrum is proportional to the number of hydrogen atoms in that chemical environment. The integration trace is sometimes shown as a line of the spectrum whose height is proportional to the number of hydrogen atoms of that type.
mass spectrometry – An accurate instrumental technique that can be used to determine the relative isotopic mass and the relative abundance for each isotope of an element in a sample. This can be used to identify the sample.
mass spectrum – A plot of the mass-to-charge ratio (m/z) of detected fragments against their relative abundance.
mass-to-charge ratio – The mass divided by the charge of an ion. Often called the m/z value.
mobile phase – The part of chromatography consisting of the mixture to be separated dissolved in a solvent and passed over/through the stationary phase. The mobile phase can be a liquid or gas.
molecular ion – The ion formed when a molecule loses an electron during mass spectrometry but does not fragment. Represented by the symbol M+.
molecular ion peak – The peak on the mass spectrum of a compound at the highest mass-to-charge ratio, which corresponds to the relative atomic mass of the molecular ion.
NMR spectroscopy – A technique used to investigate the chemical environment of isotopes in a molecule which have an odd mass number (and so exhibit spin). NMR spectroscopy gives us information about the local environment of specific atoms in a molecule, and so can be used to deduce information about the molecular structure of a sample.
NMR spectrum – A plot of the different chemical shift values (in parts per million, or ppm) of peaks found in NMR analysis of a compound. NMR spectra usually give information about the local chemical environments of 13C or 1H atoms in a molecule. Integration of the area under the peaks in a 1H NMR spectrum gives the relative number of protons in each type of chemical environment. Splitting of peaks in a 1H NMR spectrum gives information about the number of protons attached to adjacent carbon atoms.
retention time – The time it takes for a component of a mixture to pass through the coil during gas–liquid chromatography.
spin coupling – A phenomenon that occurs as the spins on atoms which are close together interact with each other.
splitting – Splitting is the name given to the observation that peaks in 1H NMR spectra often appear as a number of clustered peaks rather than one single peak. This is due to spin coupling interactions between adjacent atoms, and therefore gives information about the number of nearby hydrogen atoms.
stationary phase – The part of chromatography that remains stationary and separates the components of a mixture by interacting with them to different degrees. The stationary phase is usually a solid, often in powder form.
thin layer chromatography (TLC) – A form of chromatography in which the stationary phase is a thin layer of adsorbent material attached to a plate of glass or plastic (TLC plate). A small drop of mixture is placed on the plate, which is placed vertically inside a jar containing solvent. This is the mobile phase, and separates the components of the mixture as it rises up the TLC plate.
TMS – Tetramethylsilane. A substance used as a reference compound for NMR as its methyl groups are particularly well shielded and so it produces a strong, single peak at the far right of an NMR spectrum.
wavenumber – The number of cycles of waves in a unit length; the reciprocal of wavelength (1 / wavelength). Usually measured in m-1 or cm-1.