НИИ ФХП БГУ

Research Institute for Physical Chemical Problems
of the Belarusian State University

Laboratory of ionometry and chemical metrology

Лаборатория ионометрии и химической метрологии



The laboratory was established in 1978. The Head of the laboratory is V. Egorov, D. Sc., Professor.


Directions of the research activity:

  • investigation of regularities of functioning of ion-selective electrodes with plasticized polymeric membranes based on the synthesized ion-exchangers and their compositions with neutral carriers;
    investigation of the influence of intramembrane and phase boundary equilibrium and diffusion processes on the membrane-solution boundary on the functioning of ion-selective electrodes;
  • synthesis of new liquid ion-exchangers and investigation of correlations between their structure and exchange selectivity;
  • investigation of the influence of intramembrane and phase boundary equilibrium and diffusion processes on the membrane-solution boundary on the functioning of ion-selective electrodes;
  • development of ion-selective electrodes for interoperation process control in pharmaceutical production;
  • development of ion-selective microelectrodes for investigation of the corrosion processes.


Main achievements:

  • higher quaternary ammonium salts which are derivatives of (2,3,4-trisdodecyloxy) benzylammonium chloride with variable steric accessibility of the exchange center [C43H7903NR1R2R3]+C1- where Rp R,, R, are methyl, octyl or hydrogen atom in different combinations have been synthesized;
  • ion exchange constants for a large number of single-charged and double-charged anions on the synthesed ion-exchangers have been determined;
  • effect of the exchange selectivity increase to double-charged anions caused by the improvement in steric accessibility of the exchange center have been revealed and theoretically substantiated, the above effect manifests itself in potentiometric selectivity as well, that allow improving the selectivity coefficients for sulfate, oxalate and hydrogenphosphate anions by 4-8 orders;
  • constants of intramembrane equilibria have been deternimed, that are constants of ionic associations of a number of anions with higher quaternary ammonium cations and conditional constants of anions complexation with the ether n-hexyl triftoratsetilbenzion acid; the influence of the ion exchanger nature on the values of these constants has been clarified; the influence of intramolecular hydrogen bond in the ions under study on the effectiveness of intramembrane ion interactions has been revealed;
  • strong effect of the diffusion factor on the ion-selective electrodes analytic characheristics in the solutions on strongly discriminating ions have been found; method i for determiming undistoreted I (thermodinamically agreed) selectivity coefficients have been suggested;
  • main principles for selectivity control of ion-selective electrodes reversible to physiologically active amine cations of different structure have been stated and particular ways for selectivity improvement have been proposed.
 

Developments:
  • sulfate-selective electrode;
  • express technique for potassium determination by potentiometric titration with sodium tetraphenylborate using potassium-selective electrode;
  • ion-selective electrodes for determination of physiologically active amines, anions of non­steroidal analgetics, penicillines and techniques of their analytical applications;
  • universal electrode and unitized technique for hydrophobic physiologically active amines determination in drugs by precipitation- potentiometric titration till fixed potential;
  • H+, Na+, CI - selective microelectrodes for the investigation of corrosion processes by the local scanning potentiometry.
 
 


 

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