Determination of fluorine in organic compounds

For method of determining correction factor see Determination of fluorine in organic compounds , Chapman, Heap and Saunders, Analyst, 1948, 73, 869. 

For an idea of some historic and more recent applications of electrochemical techniques, the reader is referred to Table 2.11 of applications providing examples of applications of electrochemical analytical techniques to elemental determinations in a variety of materials. Shearer and Morris (1970) report on the microdetermination of fluorine in organic compounds with a fluoride ion electrode following an oxygen flask combustion based on the careful work of Morris. Dabeka et al. (1979) developed a microdiffusion and fluoride-specific electrode determination of fluoride in foods. Determination of lead and cadmium in foods by anodic stripping voltammetry ... 

The procedures described next are restricted to the determination of chlorine in organic compounds containing phosphorus or fluorine, or both, in the presence or absence of sulfur. For compounds containing little, if any, hydrogen a preferred alternative procedure is given. The determination of iodine or bromine in the presence of phosphorus or fluorine is not included since the determination of these halogens is, in this instance, best completed by other well known volumetric methods, such as Leipert s method for iodine and oxidation to bromate for bromine. 

P. Venkateswarlu, Sodium biphenyl method for determination of covalently bound fluorine in organic compounds and biological methods. Anal. Chem. 54 (1982) 1132-1137. 

After cooling, the flask is shaken thoroughly and disassembled, and the inner surfaces are cai-efully rinsed. The analysis is then performed on the resulting solution. This procedure has been applied to the determination of halogens, sulfur, phosphorus, fluorine, arsenic, boron, carbon, and various metals in organic compounds. 

The Th complexes with organic reagents have been applied in determinations of fluoride in waters [57] and in organic compounds [4,56]. The Alizarin S method has been automated [55]. The aluminium complex with Xylenol Orange has been used for determining fluorine in phosphates [59]. Fluorine was determined in dental preparations with the use of methylsalicylic acid [43]. 

NMR spectroscopy has also been used for elemental analysis. For example, it is possible to make accurate quantitative determinations of total hydrogen in organic mixtures. Likewise, the resonance of fluorine-19 can be used for the quantitative analysis of that element in organic compounds — an analysis that is difficult to carry out by classical methods. For quantitative work, a low-resolution or wide-line spectrometer may be used. 

For our investigations on organic compounds containing fluorine, it was of vital importance to have trustworthy methods of determining the fluorine contents of the compounds. In a report to the Ministry of Supply1 we described the macro-methods that we had found satisfactory for the types of compounds under investigation. 

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