Thermal analysis techniques underlying principles

In undertaking this project we wanted to write a book that described the underlying principles of the various thermal analysis techniques in a way that could be easily understood by those new to the field but sufficiently comprehensive to be of value to the experienced thermal analyst looking to refresh his or her skills. We also wanted to describe the practical aspects of thermal analysis, for example, how to make proper measurements and how best to analyze and interpret the data. We wrote this book with a broad audience in mind, including all levels of thermal analysts, their supervisors, and those that teach thermal analysis. Our purpose was to create a learning tool for the practioner of thermal analysis. 

More than brief discussion of the numerous ways in which end points can be taken other than by visual methods is beyond our scope. For example, end-point techniques may involve photometry, potentiometry, amperometry, conductometry, and thermal methods. In principle, many physical properties can be used to follow the course of a titration in acid-base titrations, use of the pH meter is common. In terms of speed and cost, visual indicators are usually preferred to instrumental methods when they give adequate precision and accuracy for the purposes at hand. Selected instrumental methods may be used when a suitable indicator is not available, when higher accuracy under unfavorable equilibrium conditions is required, or for the routine analysis of large numbers of samples. 

The general principle of mass spectrometry (MS) is to produce, separate and detect gas phase ions. Traditionally, thermal vaporization methods are used to transfer molecules into the gas phase. The classical methods for ionization are electron impact (El) and chemical ionization (Cl). Most biomolecules, however, undergo severe decomposition and fragmentation under the conditions of both methods. Consequently, the capabilities of mass spectrometry have been limited to molecules the size of dinucleotides [1]. Analysis of oligonucleotides with a mass range of up to 3000 Da became feasible with the development of plasma desorption (PD) methods [2]. However, until the invention of soft ionization techniques such as ESI- and MALDI MS, mass spectrometric tools were not widely considered for routine applications in biological sciences. 

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