The lower limit of reliability was found at a concentration of about 8 mg. of lactose per 100 ml. of protein-free filtrate.The procedure developed for pure sugar solutions was applied directly to zinc sulfate-barium hydroxide filtrates of mammary gland homogenates. Among the substances that were frequently added to homogenates such as adenosine triphosphate, diphosphopyridine nucleotide, magnesium chloride, succinate, phosphate, fructose diphosphate, and creatine, only the last compound was found to interfere with the sugar determinations.When galactose was not added the analysis was somewhat simplified. No galactose could be detected in lactating tissue and the glucose content was also very low.Although the glucose content was generally determined by difference, it was found possible to obtain an independent check by the use of the Tauber-Kleiner method (Iñ). SUMMARY Each of the methods investigated is applicable to the determination of lactose in mammary homogenates, and presumably other similar materials, when glucose and galactose are the only other sugars present. Each substrate or coenzyme added had to
The negative ion spectrum of C8F16O6 at low electron energies has been obtained using the mass spectrometer. The most intense peaks are identified as C8F16O—, C7F14—, C5F9O—, C4F8O—, C4F7O—, C3F6O—, and CF3O— ions. Formation of the CF3O— ion requires a rearrangement process. Appearance potentials and attachment energy ranges of the most intense peaks are given. Positive and negative ion fragmentation of the molecule is discussed relative to the components of the mixture, perfluoro-2-butyltetrahydrofuran and perfluoro-2-propyltetrahydropyran and its separation.
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