Determination Of Total Fluoride Research Articles

Determination of Total Fluoride in Boron-containing Solutions

We describe a pretreatment method before determining the total fluoride in solutions containing tetrafluoroborate ion (BF(4)(-)) with ion-selective electrodes (ISEs). BF(4)(-) was quantitatively converted to free fluoride by reacting with aluminum ions. The total fluoride concentration was then determined by ISE analysis without preliminary steam distillation using a tartrate- and tris(hydroxymethyl)methylamine (TRIS)-based total ionic strength adjustment buffer (TISAB). We investigated the effects of various factors on the decomposition of BF(4)(-) with aluminum ions, including the concentration of aluminum, pH, reaction temperature, and reaction time. The quantitative decomposition of BF(4)(-) was complete after 2 h at 50 degrees C or 1 h at 70 degrees C.

Determination of Total Fluoride in Oral Products by Using of Potentiometry With Ion Selective Electrode: A Critical Study

ABSTRACT In this work, a critical study of the determination of fluoride in oral products with an ion selective electrode was performed. The influence of the type of fluorine compound in the sample as well as the practical factors involved in the analysis were investigated. Fluoride could be determined, directly, in samples where it is in the form of NaF or SnF2. However, in samples where it is as MFP (sodium monofluorophosphate) an acid treatment was needed for removal of fluoride from the PO4F2− ion. In both cases, problems were noted related to the continuous use of the electrode, caused by the adsorption of fluoride ions onto the electrode surface. This problem was solved by using of KOH and Al2(SO4)3 solutions. Good results were obtained for the analysis of real commercial samples.

Correspondence. Fast determination of total fluoride by direct potentiometry in samples of aluminium fluoride and cryolite

Correspondence. Fast determination of total fluoride by direct potentiometry in samples of aluminium fluoride and cryolite

Determination of fluoride in complex liquid matrices by electrothermal atomic absorption spectrometry with in-furnace oxygen-assisted ashing

A new chemical method is reported for the determination of total fluoride in complex liquids and suspensions, such as fruit juices, urine, serum and blood. It is based on the formation of the A1F radical in a graphite furnace afterin situ oxygen-assisted ashing of the untreated sample. The absorbance of this radical is measured at 227.45 nm. The method is relatively easy to use and provides a low detection limit (14 ng/ml) and reasonable reproducibility (5–10%).

Determination of total fluoride in soil and vegetation using an alkali fusion-selective ion electrode technique

Determination of total fluoride in soil and vegetation using an alkali fusion-selective ion electrode technique

Determination of Total Fluoride and/or Fluosilicic Acid Concentration by Specific Fluoride Ion Electrode Potentiometry

Abstract A method is presented to determine total fluoride and/or fluosilicic acid concentrations directly, using the fluoride ion selective electrode. Samples can be analyzed at 20–30/hr with excellent precision; results are equivalent to those obtained with the AWWA standard t e s t procedure No. B 703–60. Hydrofluoric acid, if present in the fluosilicic acid samples, interferes in the calculation for H2SiF6 concentration but not for total fluoride present. Specifically, the fluoride ion is freed from fluosilicate a t pH 8.4–10.0; in addition, iron and aluminum hydrous oxides are formed at this pH. Then the solution is buffered to pH 5.7–5.9 at a fixed ionic strength with ammonium acetate buffer and the total fluoride is determined from a prepared calibration curve or computer program.