[en] The mixture of ionogenic substances is separated and concentrated into zones with equal mobility using the isotachophoretic technique. A radioactive compound or mixture of radioactive and non-active compounds is analyzed in one or two conjugate steps either separately or from one sample feed. Qualitative and quantitative evaluation is made by measuring the response of one or two parameters of which one is the measurement of activity and the other, e.g., the measurement of conductivity. The equipment for the implementation of the method consists of a voltage supply, a unit for leading and trailing electrolyte with a sampler, a capillary or groove, radiometric or other detectors and evaluation electronics and recording equipment and a fractionation cock. The equipment may be completed with a similar unit for pre-separation. (Ha)

[en] The instrument consists of a scintillation detector in which a capillary runs through a channel in the scintillation material which is fixed in a plexiglas holder. Radioactive material running through the capillary excites scintillations in the scintillation material which are processed with a photomultiplier. The advantage of the design is its simplicity and the possibility of online detection of radioactive substances separated by isotachophoresis. (J.B.)

[en] The radiometric detector is located on the surface of the capillary made of plastic material. Measurements are made through a slot in a lead plate into which the capillary is inserted. Ionizing radiatin is detected with the detector, e.g., a Geiger-Mueller tube. The design allows the direct detection of radioactive materials following their isotachophoretic distribution in the capillary. (J.B.)

[en] The use of isotope dilution technique to eliminate problems associated with demands for a high load capacity in column-coupling capillary isotachophoresis was studied. Determinations of phosphate present in a model mixture and in white wine served for the evaluation of this approach to quantitative analysis in isotachophoresis. A high selectivity of the analysis with acceptable accuracy and precision of the determination also in complex ionic mixtures in a short time are obvious advantages of this approach. (author)

[en] Various sorbents recommended for solid phase extraction (SPE) in sample preparation procedures were studied for use in combination with capillary isotachophoresis (ITP). They were very efficient in achieving trace concentration levels (low ppb, i.e., low parts per 10⁹) for different types of ITP analytes present in environmental and biological matrices. A macroporous carbon sorbent was convenient for sample preparation in ITP analysis of short chain fatty acids (C₄-C₉) in drinking water. Chelating sorbents based on hydroxyalkyl methacrylate matrix with salicylate, thioglycolate and 8-hydroxyquinolinate functionalities were found to be very suitable for preconcentration of heavy metals with an inherent sample clean-up. An octadecyl-bonded silica sorbent enabled in ITP a photometric detection of γ-aminobutyrate (labeled with a 2,4,6-trinitrophenyl group) at concentrations considerably lower than required for the determination of this amino acid in cerebrospinal fluid (∼5*10^-8 mol/l). (author) 34 refs.; 3 figs.; 1 tab

[en] A review of analytical potentialities of the isotachophoresis-capillary zone electrophoresis (ITP-CZE) is given. 10 refs

[en] The principle of operation, the design and connection of a radiometric detector for capillary isotachophoresis are described. This is an on-line detector with a plastic scintillator designed for the detection of high and low-level beta sources with a cell volume of 210μl and a detection limit of 37 Bq for 14_C. (author). 6 figs., 2 refs

[en] Isotachophoresis applications are described, e.g., in the analysis of surface water, agricultural produce control (e.g., milk), in monitoring weed killer levels, in pharmaceutical analysis, in biochemistry, clinical analysis, etc. The isotachophoretic instrument designed consists of a separation and a control unit. The control unit comprises an 8 bit MHB 8080 microprocessor, a 12-bit AD/DA converter and a backup memory of 2 kB C-MOS RAM + 6 kB ROM. The main part of the separation unit consists of an analytical column with a UV detector. An on-line radiometric detector is used for detection of weak and strong beta sources (¹⁴C, ³²P). It can easily be fitted to the isotachophoretic analyzer developed. (E.J.). 1 fig., 1 tab., 55 refs

[en] To investigate the electrochemical properties and stability of our samples, we used cyclic voltammetry and electrochemical impedance spectroscopy. We found that PEG-PPy layer on the particles FePO₄ considerably increased material conductivity in comparison with a layer of pure PPy. It also improved the incorporation of Li⁺ ions into FePO₄ structure during charging and discharging. (Authors)

[en] Short communication