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Chapter

Cover Inorganic Spectroscopic Methods

Mass spectrometry  

This chapter focuses on mass spectrometry. Although mass spectrometry is not strictly a form of spectroscopy, in that it does not involve the interaction of radiation with matter, it is nonetheless a very useful method for identifying unknown compounds. One of the reasons it is so useful is that it can provide information about the relative molecular mass of a compound. In fact, mass spectroscopy will usually provide a lot more information than just the mass of compounds; it is frequently possible to determine which ligands or groups of atoms are bonded together from the way the compound breaks up or fragments during the experiment. Mass spectroscopy requires that the molecule of interest is charged; this then provides a basis for separating the different ions due to their mass-to-charge ratio. The chapter then looks at ionization methods and the interpretation of mass spectra.

Chapter

Cover Human Physiology

Key concepts in chemistry  

This chapter describes the basic structure of atoms and molecules and explains how molecules are bound together. Examples include covalent and ionic bonds. The chapter presents a brief account of the chemistry necessary to understand the metabolic reactions of the body. All matter is composed of chemical elements, which are substances that cannot be broken down into simpler materials by chemical means. The chapter provides information which helps the reader to understand what is meant by an element and a compound, to differentiate between atoms and molecules, to understand molecular structures, and to calculate the concentration of a substance in solution. It discusses key properties of solutions such as ionization, pH, and osmosis.

Chapter

Cover An Introduction to Medicinal Chemistry

The opioid analgesics  

This chapter starts by desribing morphine extracted from opium and explains why it is known as one of the oldest drugs used in medicine. It considers morphine as a powerful analgesic that has various side effects, the most serious being respiratory depression, tolerance, and dependence. It also analyzes the important binding groups on morphine, such as the phenol, the aromatic ring, and the ionized amine. The chapter explores different analgesic receptors with which morphine interacts. these require the presence of a pharmacophore because of the need for binding groups. The chapter points out how the ability of opioids to cross the blood–brain barrier plays an important role in analgesic activity.

Chapter

Cover Mass Spectrometry

Methods of ionization  

This chapter examines the most common ionization techniques in mass spectrometry (MS), demonstrating the process of forming positively or negatively charged ions from analyte molecules. It mentions how ions can be electrically or magnetically manipulated inside the high vacuum of a mass spectrometer to facilitate mass measurement. It also highlights different mechanisms of ion formation, basic ion-source designs, their relative performances, and areas of application. The chapter explores the development of MS as a pre-eminent analytical technique, including its applications in modern physical, biological, and medical sciences. These have been driven by the development of new ionization methods. It covers ionization methods that are distinguished by the physical characteristics of the ionization process, such as desorption ionization and atmospheric pressure ionization.

Chapter

Cover Biophysical Techniques

Mass spectrometry  

Introduction Mass spectrometry (MS) is a technique that measures the mass/charge ratio of particles (this simply means that a protein with mass 25 kDa (m) and charge +5 (z) will be defined by [math]). Mass...

Chapter

Cover Molecular Spectroscopy

Photoelectron spectroscopy  

This chapter discusses photoionization, which is a process carried out in a gas phase that gives a large amount of energy to a molecule to make it ionize. It refers to the photoelectric effect in which radiation of a variable frequency is shone on the surface of an easily ionizable metal, such as an alkali. It also examines the energy required to ionize a hydrogen atom in a particular orbital and remove the electron from the influence of the Coulombic attraction of the nucleus. The chapter then clarifies how the ionization energy can be equated with the energy required to remove an electron from a particular molecular orbital of the molecule. It cites an experiment wherein the monochromatic radiation in the vacuum is focused onto a gaseous sample of molecules, which causes them to be ionized.

Chapter

Cover Process Development

Pre-reaction equilibria  

This chapter evaluates pre-reaction equilibria. Equilibria involving either organic or inorganic species can play an important part in influencing both the reaction and workup stage of organic syntheses. In the reaction stage, these equilibria can determine the proportion of reactive species present, which may not be the same as the total or stoichiometric concentration, and can thus influence both the rate and selectivity of the reaction. During workup, the same principles can determine the actual concentration of species involved in crystallisation or extraction processes. The chapter then looks at examples of the influence of pre-equilibria, as well as multiple ionisation in aqueous systems. It also considers homoconjugation, the situation where a product of an equilibrium reacts with the starting material. Finally, the chapter explains the more complex systems of nitrosation and diazotisation.

Chapter

Cover Tools and Techniques in Biomolecular Science

Mass spectrometry  

James R. Ault and Alison E. Ashcroft

This chapter explains the use of mass spectrometry, an analytical technique for probing biomolecules. The chapter gives a closer look at the basic principles of how spectrometers work and how samples are prepared for analysis. It introduces the basic components of a mass spectrometer which are the ionization source, mass-to-charge analyser, and detector. It also describes electrospray ionization and matrix-assisted laser desorption ionization-the two ionization techniques recommended for the analysis of biomolecules. Moreover, it explores some of the applications of mass spectrometry in biomolecular research. The discussion in this chapter covers peptide sequencing, the study of non-covalent interactions in biomolecular complexes, and the detection of pharmaceutical products in river water.

Chapter

Cover Elements of Physical Chemistry

Periodic trends of atomic properties  

This chapter accounts for the periodicity of atomic properties and the structure of the periodic table, including atomic and ionic radii, ionization energies, and electron affinities. It analyzes trends in the variation of atomic and ionic radii and ionization energies which can be correlated with the effective nuclear charges of atoms. It also discusses the periodic recurrence of analogous ground-state electron configurations wherein the atomic number increases accounts for the periodic variation in the properties of atoms. The chapter emphasizes two aspects of atomic periodicity which can be correlated with the effective nuclear charge: atomic and ionic radius and ionization energy. It looks at the atomic radius of an element that is half the distance between the centres of neighbouring atoms in a solid or in a homonuclear molecule.

Chapter

Cover Process Development

Equilibria in multiphase systems  

This chapter addresses equilibria in multiphase systems. Many processes are operated under conditions where more than one phase is present. This is often due to economic considerations: when it is necessary to contact large water-insoluble reactants with inorganic reagents, reactions are frequently run with either a separate solid phase or else a solution phase containing the inorganic reagent. Workup processes frequently involve the washing of a solution of a water-insoluble product which is dissolved in an organic solvent such as toluene with water in order to remove inorganic residues. The chapter then looks at simple distribution equilibria; solubilities of ionisable substrates; liquid–liquid partition of ionisable substrates; and ternary phase diagrams.

Chapter

Cover Physical Chemistry for the Life Sciences

Fundamental processes  

This chapter covers a widely used approach in thermodynamics — breaking down the process of interest into a series of simpler steps. The enthalpy change associated with the overall process is then equal to the sum of the changes for the individual steps. Commonly occurring steps include phase transitions, ionization and electron gain, and bond dissociation and formation. Phase transitions include freezing, melting, vaporizing, and their analogues in membranes. Ionization is the process of losing one or more electrons and electron gain is the opposite. Bond dissociation and bond formation are fundamental steps in many chemical reactions, and are essential components in the analysis of the overall enthalpy change accompanying a biochemically significant reaction. To describe these processes quantitatively, the chapter discusses the necessity of specifying the conditions, such as the pressure and temperature, under which they take place.

Chapter

Cover Foundations of Inorganic Chemistry

Hydrogen  

This chapter evaluates hydrogen, which is by far the most abundant element in the universe and all the other chemical elements are made from it. Without hydrogen there would be no water to drink, and DNA molecules would not form the double-helix structure that allows our genetic code to be copied and passed on to future generations. Hydrogen can form a positive ion like the metals of Group 1 but, since it is one electron short of a noble gas configuration, it can also form a negative ion and a single covalent bond, like the halogens of Group 17. Hydrogen forms compounds with many other elements but the properties of these hydrides vary considerably. The chapter then considers the self-ionization behaviour of water, which may be regarded as an acid—base reaction. It also looks at sulphuric acid and nitric acid.

Book

Cover Mass Spectrometry

James McCullagh and Neil Oldham

Mass Spectrometry firstly introduces this topic. The next chapter looks at methods of ionization. Chapter 3 covers methods of mass analysis. The next chapter looks at resolution, accurate mass, and sensitivity. Then the text turns to look at tandem mass spectrometry. It also offers an interpretation of mass spectra and separation techniques and qualifications. Finally, the text looks at mass spectrometry applications.

Chapter

Cover Mass Spectrometry

Tandem mass spectrometry  

This chapter highlights the basic principles of ion fragmentation in a mass spectrometer and examines the methods used to induce dissociation. It describes the common tandem mass spectrometer designs and explains the experiments they make possible. It also mentions electron ionization (EI) as one of the methods of ionization that impart sufficient internal energy into the newly formed molecular ion to promote a significant amount of fragmentation. The chapter reviews cases wherein ions are isolated inside tandem mass spectrometers according to their m/z and are dissociated to enable examination of the resulting products. It shows how an MS/MS spectrum can be generated by isolation and activation of an ion from the corresponding MS spectrum.

Chapter

Cover Chemistry3

d-Block chemistry  

This chapter describes the d-block elements, which are all metals and are among the most useful of all the elements. Nowadays, many of the d-block metals are used in construction materials and nine of the elements are essential for life, and compounds of the d-block elements are used as catalysts, pigments, and medicines. The chapter looks at the trends in atomic radii, ionic radii, and ionization energies across the first row of the d block. It explains why the second and third row elements in a d-block triad have similar chemistries but are rather different from the first row element. It discusses the valence electronic configuration for any d-block ion and the general trend in the most stable oxidation states of the first row d-block elements, including its origin.

Chapter

Cover Making the Transition to University Chemistry

The Halogens  

This chapter discusses the halogens, also known as either Group 17 or Group VII. It also notes the exception of featuring astatine due to its high radioactivity. The physical properties of the halogens range between the melting points, boiling points, atomic radius, ionic radius, electronegativity, ionization energy, and dispersion forces. Additionally, the oxidizing ability of the halogens decreases in positivity, while the reducing ability of the halide ions increases. Fluorine is known to be exceptionally strongly oxidizing. Aqueous halide ions are tested by adding aqueous silver nitrate acidified with dilute nitric acid. An equilibrium is set up when chlorine dissolves in water.

Chapter

Cover Inorganic Chemistry

Atomic structure  

This chapter provides foundations for an explanation of the trends in the physical and chemical properties of all inorganic compounds. The chapter begins with a discussion on the origin of matter in the solar system and then considers the development of understanding of atomic structure and the behaviour of electrons in atoms. It reviews the structures and properties of atoms, acknowledging that these are crucial in understanding the behaviour of molecules and solids. The chapter also qualitatively introduces quantum theory and uses the results to rationalize properties such as atomic radii, ionization energy, electron affinity, and electronegativity.

Chapter

Cover Chemical Structure and Reactivity

Trends in bonding  

This chapter addresses how an understanding of the way in which orbital energies and sizes vary across the periodic table enables one to rationalize the nature of the bonding between elements. It begins by considering the electronic configuration of the elements, and the energies of the occupied orbitals. The variation in orbital energies across the periodic table can be understood in terms of the increase in nuclear charge, the extent to which different electrons screen one another from the nucleus, and the shell to which a particular orbital belongs. The concept of the effective nuclear charge experienced by an electron is a useful way of rationalizing trends in the sizes of orbitals, ionization energies, and electron affinities. The chapter then looks at the bonding between atoms of the same element, and how the nature of this bonding affects the structure and physical properties of the element.

Chapter

Cover Making the Transition to University Chemistry

Atomic Structure  

This chapter looks at the atomic structure and shows that atoms are bonded together to form compounds. The chapter atoms, nucleus, electron, proton, and neutron by referring to the nuclear model. A mass spectrometer can be used to measure the masses of atoms. Electronic structures are often called electronic configurations. The Schrödinger equation can be used to explain arising subshells in the configuration and the electron density. The electron density is defined as the probability of finding a particular electron. The chapter also shows how the current numbering system of the periodic table is based on the Schrödinger equation. The chapter then tackles the ionization energy. This refers to the minimum energy required to remove an electron from an isolated gas atom.

Chapter

Cover Making the Transition to University Chemistry

Group 2  

This chapter examines the group for alkaline earth metals, also referred to as Group 2 or Group II. The elements in Group 2 are all metals with low electronegativities. Beryllium and radium are the focus across the chapter as they have been less researched due to their toxic compounds or radioactive elements. The physical properties of the Group 2 elements include the increasing atomic radius and ionic radius and decreasing ionization energy and sulfate solubility. Group 2 showcases increasing reactivity with water, acids, and hydroxide solubility. The chapter also looks into the insolubility of barium sulfate and its test for the sulfate ion.