Fluorine in biological systems

The fluorine MR signal in vivo will depend upon both the fluorine concentration and the compound s MR visibility [1, 3, 5, 7-9, 19, 20, 71]. Like protons, 19F nuclei have spin 1/2 with 100% natural abundance however, 19F has sensitivity of 83% relative to protons (see Table 19.1) [71]. Unlike protons, which are ubiquitous, there are no natural occurrences of MR-visible fluorine at sufficiently high concentration to be observed by MR in biological systems and hence there is no background fluorine signal. Physiological fluorine... 

Barnett, J. E. G. Fluorine as a Substituent for Oxygen in Biological Systems Examples in Mammalian Membrane Transport and Glycosidase Action. Amsterdam Ciba Foundation Symposium Associated Scientific Publishers, 1972, pp. 95-115. 

MacNicol and Robertson [37] have cautioned that perfluorochemicals cannot be assumed to be inert in biological systems. Kissa and Kinney [29] found, however, that the presence of fluorinated surfactant-related organic fluorine in blood does not affect the inorganic fluoride concentration significantly (Table... 

Chapter 1 presents an overview of fluorinated surfactants. The synthesis of fluorinated surfactants is discussed in Chapter 2. Since the space limitations precluded a detailed description of processes, patent citations are augmented by references to Chemical Abstracts. Physical and chemical properties are reviewed in Chapter 3. Chapters 4-7 are devoted to the theory of fluorinated surfactants liquid-vapor and liquid-liquid interface (Chapter 4), solid-liquid interface (Chapter 5), solutions of fluorinated surfactants (Chapter 6), and the structure of micelles and mesophases, including mixed surfactant systems, in Chapter 7. The practical application of fluorinated surfactants is the subject of Chapter 8. Various applications are listed in alphabetical order for easy access to information. Chapter 9 reviews the analytical and physical methods for the investigation of fluorinated surfactants. Chapter 10 examines the environmental and toxicological aspects, including the use of fluorinated surfactants in biological systems. 

Fluorine-19 NMR spectroscopy has been used to study biological systems in a number of ways. Structural information can be obtained if the fluorine is used as a probe, for example as part of an amino acid in a protein. Biochemical pathways can be elucidated by observing the fluorine-19 chemical shifts of products and intermediates which are usually well separated owing to the wide chemical shift range. Finally, the distribution of fluoro-organic molecules within an organism can be detected using such techniques as surface coils. 

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