NMR Spectroscopy:: Processing Strategies (Bigler, Peter)

• Nancy S. Mills ^[1]
  1. [1] University of Colorado, Department of Chemistry & Biochemistry
• Localización: Journal of chemical education, ISSN 0021-9584, Vol. 75, Nº 6 (June), 1998, págs. 696-696
• Idioma: inglés
• Texto completo no disponible (Saber más ...)
• Resumen

  • This book, part of a four-volume series planned to deal with all aspects of a standard NMR experiment, is almost the exact book I have been hoping to find. My department has acquired, as have hundreds of other undergraduate institutions, high-field NMR instrumentation and the capability of doing extremely sophisticated experiments. However, the training is often a one- or two-day experience in which the material retained by the faculty trained is garbled and filled with holes, not unlike the information our students seem to retain. This text, and the accompanying exercises based on data contained on a CD-ROM, goes a long way to fill in the gaps and clarify misunderstandings about NMR processing.

    The text uses the Windows-based program WIN-NMR, a Bruker software product, to demonstrate processing 1- and 2-D spectra. The program and NMR data sets are contained on a CD-ROM and require an IBM-compatible 386, 486 or Pentium class PC with a minimum of 4 MB RAM. A hard disk with at least 100 MB spare capacity is recommended. I was initially skeptical about the value of the approach because I am only familiar with Varian software and am a Mac user; but I found the Windows-based program almost as easy to use as a Mac program. More importantly, although the WIN-NMR software uses very different commands from Varian software, the philosophy of the approach was so transparent as to make it reasonably straightforward to take what was learned via WIN-NMR and apply it in a Varian setting.

    The book begins with a section that describes the various types of NMR experiments, including the phase-sensitive double quantum filtered COSY, TOCSY (total correlation spectroscopy), and ROESY (rotating frame Overhouser effect spectroscopy) experiments. The descriptions are enhanced editorial comments that contrast the various experiments, suggesting the situations in which each is most appropriate. The remainder of the book is a set of exercises using data on per-acetylated β-D-glucose from a wide variety of NMR experiments. The reader is led through simple commands on already processed FIDs through sophisticated processing of 1- and 2D data sets.

    The real advantage of the exercises lies in two areas. First, the authors give nuts and bolts suggestions on processing strategies that are far more helpful than I have found in any other reference. Second, the processing and display is done on good data sets. When one is unable to extract information from one's own experiments, it is difficult to determine whether the fault is in the processing or in the data itself. These data are good, so one area of ambiguity is removed. In addition, all data sets contain both the FID and a data set that is already Fourier transformed and phased. Thus you can see what the data should reveal and have a standard against which to compare your own attempts. My only real complaint with the text was the authors' tendency to instruct the reader to explore processing variations until the result looks good. For a novice, the ability to discern good is pretty poor.

    The authors led me through processing and displaying phase-sensitive data sets like phase-sensitive COSY, as well as ROESY and NOESY experiments. Phase-sensitive experiments are particularly difficult to process because some of the peaks are supposed to be inverted. Because I now have a sense of what the experiment is supposed to give, I have much more confidence in my ability to extract that information from my own experiments. The last section on advanced processing techniques, from weighting the FID to linear prediction, suggests that data sets I have thrown away because I felt that they were irrevocably flawed might have been salvageable. This is particularly crucial for my research, which involves NMR studies on unstable dications made from compounds that may have taken an undergraduate student weeks to make. If I can salvage some of the data, I have saved myself and my student a great deal of effort.

    I initially assumed that the appropriate audience for this book was the owner of a Bruker NMR spectrometer. However, as indicated in the beginning, the information appears transferable to a variety of spectrometers and I now feel that anyone who owns a high-field NMR spectrometer and who wants to exploit its full power should own this book. The learning curve for the processing of data from sophisticated NMR experiments is very steep. This book goes a long way toward giving the practical information needed to effectively use the data that the spectrometer can provide with such ease.