Search results for "Conductometry"

Determination of organic and inorganic anions in insect haemolymph and midgut contents by ion chromatography

1997

A simple and rapid ion-exchange chromatographic method with conductimetric detection for the determination of carboxylic acids (succinic, malic and citric) and inorganic anions (chloride, phosphate and sulphate) in haemolymph and midgut content of Lepidoptera larvae is provided. The mobile phase is 0.975 mM phthalic acid at pH 4.1. The procedure of sample extractions was simple. Comparison of the results with whose reported in the bibliography showed that the values were similar. The ion-exchange chromatographic–conductimetric detection method permits the analysis of various organic and inorganic anions in small biological samples.

Structural and dynamical investigation of gelation containing water-in-oil microemulsions

1996

The gelatin (Bloom 300)/water/AOT/n-heptane system has been investigated at fixed water/AOT molar ratioR (R=31.1) as a function of the gelatin content. Several experimental techniques (densitometry, refractometry, conductometry, rheology, dielectrometry, ultrasonics, hypersonics) have been used to investigate the role played by the gelatin molecule in the observed sol-gel transition above a critical gelatin content. The results appear consistent with the hypothesis of a rigid network of gelatin-water rods coated by surfactant molecules coexisting with gelatin-free AOT reversed micelles at the gelation point.

Bis(2-ethylhexyl)phosphoric acid/bis(2-ethylhexyl)amine mixtures as solvent media for lithium-ions: A dynamical study

2016

Abstract The self-diffusion coefficient, the spin-lattice relaxation times and ionic conductivity of lithium ions in liquid mixtures composed of bis(2-ethylhexyl)amine (BEEA) and bis(2-ethylhexyl)phosphoric acid (HDEHP) have been thoroughly investigated as a function of composition and temperature by NMR spectroscopy and conductometry. While the temperature and composition dependence of diffusion coefficients of lithium ions follow the same trend observed for those of the surfactant molecules, the spin-lattice relaxation times of lithium ions and 1 H are remarkably different. The observed behavior has been interpreted in terms of lithium ions diffusion occurring through its association with…

Ion-Selective Organic Electrochemical Transistors

2014

Ion-selective organic electrochemical transistors with sensitivity to potassium approaching 50 μA dec(-1) are demonstrated. The remarkable sensitivity arises from the use of high transconductance devices, where the conducting polymer is in direct contact with a reference gel electrolyte and integrated with an ion-selective membrane.

[99mTc]Ca-Phytate: Some colloidal characteristics related to the optimal preparation conditions

1983

Abstract Some physico-chemical characteristics of the colloidal radiopharmaceutical [ 99 m Tc]Ca-phytate related to optimal preparation conditions have been studied. (1,2) It is demonstrated that the Ca 2+ -phytate stoichiometry is 6:1. Two different Ca-phytate colloids seem to be formed, mainly depending on the Ca 2+ :phytate molar ratio-one of low mycelar size for a 1:1 Ca 2+ :phytate molar ratio ( cmc ∗ = 5.10 −5 M ) , and another one, with a higher mycelar size for a 6:1 molar ratio (cmc = 8.10 −5 M). This last one it probably better for providing a good quality splenic uptake.

Old Principle of Liquid Ion-Impedance Spectrometry (Particularly in Milk) Realised by New Components

2020

Abstract Ion impedance spectrometry enables detection of the concentrations of multiple chemical compositions in a weak solution, usually if only part of a complex signal is used and the frequency is not swept. Prior to the method described in this paper, ion impedance required rather sophisticated electronics to collect the results from an instrument, as well as the electrode polarisation minimising. We elaborated and tested circuitry that uses the newest electronics components for a chemical analysis instrument designed according to a principle patented in Latvia (No. SU-1021440A), year 1981. The newly improved ion impedance spectrometry apparatus is suited for accurate measurement of ion…

Spectroscopic and structural characterization of pure and FeCl3-containing tri-n-butyl phosphate

2014

The spectroscopic properties and liquid structure of pure tri-n-butyl phosphate (TBP) and FeCl3/TBP solutions have been investigated by Uv–Vis and Raman spectroscopies, X-ray diffraction and conductometry. Uv–Vis and Raman spectra, supported by conductometric measurements, consistently indicate that the solubilized salt is present mostly as TBP n [FeCl3 − n ] n+ and FeCl4 − complex ions due to specific interaction with the TBP phosphate group. Thanks to this interaction, a high amount of salt (up to 13 % w/w) can be dissolved despite the relatively low dielectric constant of TBP. The X-ray diffractogram of pure TBP has been interpreted in terms of three main contributions which can be attri…

1983

Water soluble polyamides with iminoethylene and oxyethylene units in the main chain were obtained by condensation polymerization of diethylenetriamine and triethylenetetramine with suitable dimethylesters containing two or three oxyethylene units. The molecular weights were in the range of Mn = 5000–7000. By potentiometric and conductometric titration only 80–85% of the expected amount of basic groups was found which was probably caused by branching. Durch Polykondensation von Diethylentriamin und Triethylentetramin mit Dimethylestern von Sauren, die zwei oder drei Oxyethyleneinheiten enthalten, wurden wasserlosliche Polyamide mit Iminoethylen- und Oxyethyleneinheiten in der Hauptkette erha…