Development Of Analytical Fourier Transform Nuclear Magnetic Resonance Spectroscopy For Sensitivity Enhancement And Mixture Analyses

The book presents developments and applications of these methods, such as NMR, mass, and others, including their applications in pharmaceutical and biomedical analyses. The book is divided into two sections. The first section covers spectroscopic methods, their applications, and their significance as characterization tools; the second section is dedicated to the applications of spectrophotometric methods in pharmaceutical and biomedical analyses. This book would be useful for students, scholars, and scientists engaged in synthesis, analyses, and applications of materials/polymers.

Although originally designed to treat neither spectroscopic nor multidimensional data, FDM was adapted to process NMR spectra of both large and small molecules in liquids in 1D, 2D, 3D, and 4D spectra, with the multidimensional cases requiring important modifications. FDM outperforms the discrete Fourier Transform (DFT) whenever sensitivity is good, the spectrum is sufficiently sparse, the spectral peaks are sharp and Lorentzian, and the extent of the measured time-domain data is short, so that the FT spectrum exhibits line shapes that are distorted only by the time-frequency uncertainty principle. A further study of FDM to perturbations under non-ideal conditions lead to further improvements and finally a multi-dimensional, phase-sensitive, hybrid FDM (HFDM) algorithm that is introduced for the first time. HFDM can enhance the resolution of peaks distorted by time-frequency uncertainty, while still producing a spectrum in which all the original imperfections are present, such that a true noise floor prevents inadvertent contouring of features that look like resonances but that would in fact be buried in noise in any decent spectral estimate. This opens the door to the application of HFDM on NMR data sets with more reliability. Mixture separation is another important area of NMR research and will be the focus of the third chapter. Separating a mixture of signals into its source components is an engaging but challenging problem relevant to research in a wide variety of fields from neurology and medical signal processing to speech recognition systems. The vast majority of NMR spectroscopic data is taken on isolated, purified compounds; yet mixtures are clearly important to tackle. The pharmaceutical industry is a key example of a field that would benefit tremendously from more robust NMR mixture separation techniques. Structural information about promising candidates from the drug design process must be extracted from samples that also contain the target molecule, side products, and impurities. NMR can identify individual samples with respect to their unique fingerprint spectra; however, it has been traditionally poor at handling mixtures. Diffusion ordered spectroscopy (DOSY) has been one of the few NMR techniques that can be used for mixture separation. It uses translational diffusion to effect a partial separation and can be quite powerful when the individual compounds have a distinguishable difference in their diffusion constants. However, the separation problem becomes more difficult when the component molecules have similar chemical functional group and overlap in their NMR spectra. Blind Source Separation (BSS) is a technique that can be used to extract an individual NMR subspectrum from spectra of a number of different mixtures; and--if the molecules do not interact strongly--these individual subspectra adhere closely to those of the corresponding pure compounds under the same conditions. Furthermore, the "mixture spectra" need not be different physical samples: any method that can modify the intensities of all the peaks from a given molecule, in concert, is applicable. Previously a mixture of two components was successfully separated. Recent efforts have uncovered a flaw in the original BSS algorithm that causes behaves erratically for samples with three or more components. This complication will be described in detail, and a newly developed approach-- dubbed "BISI" for Blind Iterative Source Identification--will be introduced that overcomes those previously unforeseen problems.

Now reprinted and available in paperback, this book is a comprehensive guide to the theory and practice of NMR spectroscopy in its many forms. It presents the whole range of Fourier Transform NMR techniques, including 2D NMR and NMR imaging. The first three chapters cover the basic physics of magnetic resonance and the mathematical background to Fourier techniques. The following chapters concentrate on pulsed NMR spectroscopy, including the new multipulse sequences, from a theoretical and practical approach. The final chapters deal with the important topic of nuclear relaxation and the novel technique of 2D NMR. The principles of NMR imaging are discussed in detail including medical applications. Containing a wealth of information on techniques and methods, the book provides the reader with a sound base from which to apply Fourier NMR techniques to the many areas of science where they are proving of most value. It is a must for undergraduate and postgraduate students in chemistry and physics, medical students involved in imaging and radiology, NMR spectrometer and NMR imaging manufacturers, and NMR research scientists.

Clear, comprehensive, and state of the art, the groundbreaking book on the emerging technology of direct analysis in real time mass spectrometry Written by a noted expert in the field, Direct Analysis in Real Time Mass Spectrometry offers a review of the background and the most recent developments in DART-MS. Invented in 2005, DART-MS offers a wide range of applications for solving numerous analytical problems in various environments, including food science, forensics, and clinical analysis. The text presents an introduction to the history of the technology and includes information on the theoretical background, for exampleon the ionization mechanism. Chapters on sampling and coupling to different types of mass spectrometers are followed by a comprehensive discussion of a broad range of applications. Unlike most other ionization methods, DART does not require laborious sample preparation, as ionization takes place directly on the sample surface. This makes the technique especially attractive for applications in forensics and food science. Comprehensive in scope, this vital text: -Sets the standard on an important and emerging ionization technique -Thoroughly discusses all the relevant aspects from instrumentation to applications -Helps in solving numerous analytical problems in various applications, for example food science, forensics, environmental and clinical analysis -Covers mechanisms, coupling to mass spectrometers, and includes information on challenges and disadvantages of the technique Academics, analytical chemists, pharmaceutical chemists, clinical chemists, forensic scientists, and others will find this illuminating text a must-have resource for understanding the most recent developments in the field.