High Fluoride Ion Concentration Research Articles

Detection of sarin in plasma of rats after inhalation intoxication

Presently used methods for detection and diagnosis of the severity of intoxication with organophosphorus (OP) compounds are mostly those that quantify inhibition of blood cholinesterases. It was found that when plasma inhibited with OP compounds is incubated in the presence of a high concentration of fluoride ions, the organophosphate is released from the enzyme thus yielding a phosphofluoridate, which can be analyzed by gas chromatography and NP detection. In our study, the concentration of sarin released after fluoride ions were added to the plasma of sarin-poisoned rats was determined. Sarin amounts in plasma measured after refluoridation and plasma butyrylcholinesterase activity in ten rats, that were exposed to sarin vapors at concentration of 1.25 μg/L (E1 group) and 2.5 μg/L (E2 group) respectively, for 60 min. In the E2 group the concentration of sarin in plasma was nearly 2-fold higher than in the E1 group. These results correspond well with the concentrations of sarin vapors to which the animals were exposed. Both experimental groups of animals showed significant decreases in butyrylcholinesterase activity by more than 30%–36.4% (E1 group) and 47.0% (E2 group). The method of fluoride-induced reactivation provides a very good marker for monitoring sarin intoxication in laboratory animals determined previously mostly by ChE determination which does not allow any information on sarin amounts in plasma.

Measurement of fluoride ion in the river-water flowing into Lake Biwa

To study the effect of biotite granite on the concentration of fluoride ion in the river-water around it, the concentration of the ion in several river-water samples flowing into Lake Biwa, in Shiga Prefecture, Japan, was measured by using ion chromatography. Several biotite granite plutons around Lake Biwa were contributed to relatively high concentration of fluoride ion in river-water around the plutons. By this study and previously reported result on the river-water flowing in the Rokko Granite, in Hyogo Prefecture, Japan, it was supposed that the degree of the distribution depends on the age of each pluton and the extent of its weathering.

19F and 27Al n.m.r. spectroscopic study of the fluoro complexes of aluminum in aqueous solution and in zeolites: Dealumination of zeolites by fluoride ions

The addition of fluoride ions to aluminum〈III〉 salts or to zeolites in aqueous solutions produces fluoro complexes of the general form [AlFitn](3itn), which have been characterized by 27Al and 19F n.m.r. Each fluoroaluminate complex has distinct 19F chemical shifts, although the 27Al chemical shifts of all of the complexes are approximately the same. The 27Al n.m.r. line width, however, changes as different complexes are formed. Zeolite reacts with aqueous fluoride ion solution at approximately neutral pH. n.m.r., FTi.r. and X-ray powder diffraction measurements suggest that the formation of fluoroaluminate species such as K2NaAlF6 at high fluoride ion concentration inside zeolite is an important dealumination mechanism.

19F Nuclear Magnetic Resonance Study on the Kinetics of the Fluoride Exchange in Uranium(VI) Fluoro Complex

Abstract Kinetics of the fluoride exchange in uranium(VI) (uranyl) fluoro complex was studied by using 19F NMR. The 19F NMR signal of coordinated fluoride at the equatorial positions of uranyl ion was first observed at about 80 ppm down field from that of bulk F−. From area measurements of the coordinated and free 19F NMR signals, penta-fluoro complex UO2F53− was confirmed to exist in aqueous solutions containing high concentration of fluoride ion. The stability constant K5 = [UO2F53−]/[UO2F42−][F−] was determined to be 1.31 mol−1 kg. The rate of F− exchange between coordinated and bulk F− was measured by the 19F NMR line-broadening method and the observed first-order rate constant kobsd was expressed as Kobsd = (k4 + k5K5[F−])[F−]/(1 + k5[F−]) where k4 and k5 are the exchange rate constants of F− between bulk and coordinated F− in UO2F42− and UO2F53−, respectively. The associative or associative interchange mechanism was proposed from the experimental results.