Fluorine Absorption Research Articles

Study on the Absorption and Urinary Excretion of Fluorine following Ingestion of Green Tea

The concentration of fluorine in the infusion of green tea, one of the staple drinks and consumed widely in Japan, was measured. A high concentration of fluorine was found in high-class tea (Gyokuro). A larger amount of fluorine was extracted from the tea at the initial infusion than in succeeding infusions. These results suggest that the high concentration and the amaint of extraction of fluorine may be a scientific base for the selecting of good tea. From these results, it was calculated that 0.48-0.97 mg of fluorine was ingested daily from green tea by Japanese adults, and it may be considered that the tea is a main source of daily fluride intakefor them. The ingestion of green tea infusion and of sodium fluoride (NaF) solution by adult men gave the following results. That is, the absorption of fluoride from green tea is apt to be slow but it is excreted via the urine with relative rapidity, as compaired with NaF ingestion ; it is inferred that the different metabolic processes may be involved in the absorption of fluoride from green tea and from NaF. From the results of urinary excretion of fluorine, it is assumed that the urinary fluorine should be estimated with fluoride quantity of urine stored for a certain duration, since the urinary fluoride concentration varied easily with the urinary volume, the collection intervals and other conditions.

Absorption and utilization in the rat of calcium and fluoride from compatible compounds.

Absorption, blood levels and skeletal uptake of fluorine (F) and calcium (Ca) from combinations of sodium monofluorophosphate (Na2PO3F) and calcium gluconate (CaGluc) were studied in rats under varying conditions. When Na2PO3F and CaGluc were ingested simultaneously in a ratio by weight F/Ca=1/50, absorption and skeletal uptake of F and Ca were parallel. This was partly due to the prolonged absorption of F under the influence of CaGluc. Hydrolysis of PO3F ions was weak in the stomach, nearly complete in the intestine and apparently complete in the blood plasma. Combined Na2PO3F-CaGluc ingestion gave a comparatively slow, moderate but prolonged elevation of the plasma F levels, while no influence on plasma Ca was found in normal rats. F and Ca absorption and skeletal uptake were increased in Ca-deficient rats and decreased in vitamin D2-intoxicated rats.

FEATURES OF INNER ATOMIC SHELL PHOTOIONIZATION IN MOLECULES

The following experimental features of ultra-soft X-ray absorption molecular spectra [l], [2] are discussed : 1. Existence of strong absorption maxima on the high energy side of ionization thresholds (in continuum) of inner shells of atoms in molecules. 2. Similarity of the fine structure of K (1 S) spectrum of fluorine and L (2 p) spectrum of sulphurin the number of maxima and their energy position with respect to ionization threshold in molecule SF6. 3. Absence of sharp rise in absorption coefficient at the ionization threshold of inner shells of the central atom surrounded by electronegative atoms in high symmetrical molecules (SF6, SiF4 and others). [l] ZIMKINA (T. M.), FOMICHEV (V. A.), Dokladi ANSSSR, 1966, 169, 1304. [2] ZIMKINA (T. M.), VINOGRADOV (A. S.) (c X-ray spectra and electronic structure of matter )) 11, I. M. F. AN USSR, Kiev, 1969. At present we have studied the ultrasoft X-ray absorption spectra of several complex inorganic molecules (SF6, SiF,, SiC14, BF,, BCl,, NF, and the others). All these spectra show a large difference of the fine structure near the absorption edges of the inner atomic shells from the well known fine structure of X-ray spectra of atoms and simple molecules. The latter consists of several discret lines lying before the absorption edge and their intensity and energy separation decrease rapidly with approach to the edge. The appearance of these lines in X-ray absorption spectra is attributed to the exciton mechanism. If the electron ejected from the inner shell moves in a CoulomL field the lines of the fine structure can be represented as a_Rydberg series of absorption lines. One of the specific feature of the ultrasoft X-ray absorption spectra of molecules consists in existence of several strong absorption lines extending over 10-20 eV. Some of these discret lines were found to be behind the absorption edge in continuum. The fine structure in these spectra cannot be attributed to transition of inner atomic electrons to a Rydberg series of excited states neither in intensity nor in the energy position before the ionization threshold. Therefore the hydrogenic model cannot be used to interpretation the ultrasoft molecular spectra. The second feature consists of absence of any detectable jump ratio at the ionization thresholds of the inner electrons of central atom in symmetrical molecules (SF,, SiF,, SiCI,, BF,, NF,, BCI,). Let's consider for a example the ultrasoft X-ray absorption spectra of SF, molecule. It is known, the X-ray absorption spectra of sulphur in SF, have unusual fine structure near the K and the LI,,,,I absorption edges [l], [2]. Recently the K fluorine absorption spectrum in this molecule has been studied [3]. Besides, the energy of l S fluorine and 2 p sulphur atomic levels in SF, molecule have been measured by photoelectron spectrometry [4]. Using these data we can compare the sulphur and fluorine spectra in the same energy scale and receive the additional information about the nature of the fine structure of SF,

An examination of the possibility of the existence of xenon octafluoride

The possibility that xenon octafluoride might exist was first suggested in 1963. Later thermochemical and theoretical work indicated that there was a marginal chance that such a compound should be sufficiently stable to isolate. Our measurements of the temperature dependence of pressure in xenon-fluorine mixtures give F:Xe ratios of 6 for temperatures from 22 to 200°C and 260 to 350°C but those between 200 and 250°C are higher. It appears that the unexpectedly high absorption of fluorine cannot be accounted for by thermal expansion of the reaction vessel, the absorption of fluorine by the walls of the reaction vessel or the non-ideality of fluorine gas. Possibly association of xenon hexafluoride under high pressure or the existence of a higher fluoride of xenon could explain the observed effect. However, isolable quantities of xenon octafluoride were not obtained and no i.r. evidence for such a compound was observed.

Magnetic Resonance Study of Molecular Motion in Cubic (NH4)2SiF6

Proton, fluorine, and deuteron magnetic resonance absorption line shapes, as well as 1H and 19F spin—lattice relaxation times, have been measured in polycrystalline cubic (NH4)2SiF6 and (ND4)2SiF6 from −170° to +100°C. The results demonstrate that the threefold proton disorder in the NH4 groups is indeed dynamic and not static, and suggest the following mode of reorientation: The NH4 tetrahedron is first excited from the ground torsional—vibrational state to nearly continuous levels above the potential barrier, and after a short interval of nearly free rotation again drops to one of the three possible equilibrium orientations in the ground state. On the average, each proton spends the same amount of time in each of the 12 equilibrium sites. Large-amplitude rotational oscilations in the ground state are also consistent with the experimental data. The existence of a 19F linewidth transition, as well as spin—lattice relaxation data, demonstrate the onset of hindered rotation of the SiF6 ions above room temperature.

Fluorine and proton spin absorption and relaxation in solid ammonium heptafluozirconate

H1 magnetic resonance absorption in (NH4)3ZrF7 has been studied over the temperature range 20° to -196°c. A line width transition due to low activation energy reorientations of two types of NH4 + ion was observed. The fluorine absorption data give also evidence of reorientation of zirconiumfluorine complex. The transient experiment carried out at 15·3 and 22·9 Mc/sec in the same temperature interval supports the absorption results by indicating conclusively that two motions are effective in the crystal studied. The slower one is the zirconium-fluorine ion reorientation, the faster one, the reorientation of the weakly hydrogen-bonded NH4 + ions. The relaxation data exhibit strong F-H and H-F cross relaxations: at higher temperatures fluorines and protons relax essentially through the slower motion of the zirconium-fluorine complex, while at lower temperatures both spins relax through the high frequency reorientation of the NH4 + ions. The observed dynamic disorder is compatible with the Hampson-Pauling int...

NMR Evidence for Contact Hyperfine Coupling in Paramagnetic UF4

AbstractThe F19 NMR absorption in powdered UF4 is investigated in the temperature range 122 to 433 °K at magnetic fields between 10000 and 5000 G. The fluorine absorption pattern in this paramagnetic material with seven nonequivalent F‐sites in the unit cell is reproduced qualitatively by a sum of six asymmetric component lines (H∥ ‐– H⊥)−1/2 × (H–H⊥)−1/2, some of which are shifted in the high field direction, and some in the low field direction. The occurrence of low‐field shifted components provides evidence of contact hyperfine interaction between the magnetic electrons and the fluorine nuclei whereas the occurrence of high‐field shifted components may arise from indirect coupling through electron transfer, and indicates partial covalent bonding between the magnetic electrons and the surrounding fluorine ions. This is supported by magnetic susceptibility and EPR data.

Nuclear Magnetic Resonance Line Narrowing by a Rotating rf Field

Nuclear magnetic resonance line narrowing was investigated by means of a rotating r-f field experiment that is analogous to free-induction decay in a rotating sample. A single crystal of uranium-doped calcium fluoride was used, and measurements were made at the same crystal orientation. An effective narrowing of the fluorine absorption line by a factor of 5 was obtained. (C.E.S.)

Absorption and metabolism of the PO3F ion in the animal body

Abstract A review of previous literature summarizes data on the biological effects of sodium monofluorophosphate. The metabolic fate of the monofluorophosphate ion in the animal body has been studied in rats with the use of sodium monofluorophosphate labelled with F18 and/or P32. It is demonstrated that the PO3F ion is split to a great extent in the body. Under the experimental conditions phosphorus is absorbed more rapidly from orthophosphate than from monofluorophosphate. When given in greater concentration and together with calcium ions sodium monofluorophosphate gives rise to a much more rapid fluorine absorption than sodium fluoride given in the same way. This difference disappears if the calcium ions are eliminated by citrate. Sodium monofluorophosphate thus gives a more stable fluoride supply than sodium fluoride, which is influenced by several calcium-rich foods.

An Evaluation of the Fluorine Dating Method

An Evaluation of the Fluorine Dating Method

Fluorine Content of some Nigerian Waters

FLUORINE absorption from drinking water during the period of calcification of the teeth has long been correlated with mottling of the dental enamel1. In East Africa the excessive amounts of fluorine in some drinking waters have become a matter for urgent consideration2; but little is known of fluorine distribution in West African waters.

British Food Journal Volume 48 Issue 10 1946

British Food Journal Volume 48 Issue 10 1946