Studies in the Mass Spectrometry of Organic Compounds

A general historical introduction begins the thesis; there follows a survey of the various types of mass spectrometers and their component parts. In order to place in perspective the main work of the thesis, which is the application of data processing to mass spectrometry, a brief introduction to this field is included. Next a review of some of the earlier efforts by R. I. Reed are discussed and the necessary background in probability and set theory is presented prior to treatment of the data processing techniques per se. Since one of the major problems of mass spectrometry is that of the vast amounts of information which must be processed in order to achieve meaningful answers, the aim of this work has been the creation and application of methods for reducing this information to manageable proportions. The first of the three methods utilizes a principle borrowed from the discipline of information theory which is commonly called the Khinchine entropy function. This principle allows creation of a single-valued fraction for each chemical compound uhder investigation. The utility of this function is discussed with illustrations of its uniqueness The second principle comes from the field of mathematics and is referred to as the divergence function. It allows comparisons to be effected between spectra thereby expressing their similarity or dissimilarity. In practice, it has been used to advantage to resolve those cases in use of the Khinchine entropy which involve two values that are not sufficiently different to be diagnostic. The third and most widely applicable principle involves coding of mass spectra in octally coded binary format: hence it has been called octal coding. Use of a code based on binary representation is most appropriate for data processing with a digital computer. The code has the special advantages of being capable of creation on-line in real-time during operation of the mass spectrometer; it also displays insensitivity to intensity factors and the presence of impurities. Examples are shown from each principle in tabular form in the body of the thesis and supplementary data is presented in the appendix. Also included there are copies of the computer programmes and related publications by the author