StatusThe thesis was presented on the 7 December, 2012 at the meeting of the Scientific Council and now it is under consideration of the National Council.
Abstract– 0.28 Mb / in romanian
1.27 Mb /
Potentiometric sensors based on trinuclear chromium(III) pivalatesˮ. Doctor’s
thesis in Chemistry. Chisinau, 2012. Introduction, three chapters, conclusions, bibliography of 153
references, 116 pages of main text, 28 figures and 35 tables. The results are published in 17 scientific papers.
Keywords: trinuclear chromium(III) pivalates, ion-selective electrodes, potentiometric sensors, ionophores,
potentiometric titration, direct potentiometric method.
Area of Research and Objectives. The thesis belongs to the analytical chemistry domain and was
aimed at investigating the possibility of using trinuclear chromium(III) carboxylates as new effective and
efficient electroactive materials for potentiometric sensor membranes, sensitive to the presence of anionic
species (perchlorate, nitrate, thiocyanate, salicylate, dodecylsulfate, tetraphenylborate, perrhenate), and with
chemometric parameters good enough for the analysis of these species in real objects. For solving these
problems the mains objectives were: the synthesis and study of trinuclear chromium(III) pivalates, which
contain as anions the above mentioned species; preparation, optimization of the composition of
poly(vinylchloride) membranes and of the operation regime of the sensors; elaboration of potentiometric
methods for determination of anionic species in real objects using these sensors.
Scientific Novelty and Originality. New original methods for the synthesis of the compounds with
above mentioned anions have been developed. These complex systems have been used for preparation of
the membranes and anionic potentiometric sensors have been elaborated. The analytical and functional
parameters (concentration range where the potential changes with pA linearly, the slope of the calibration
curve, selectivity, response time and life time) have been determined. The interference of other species on
these parameters and behavior of the electrodes in policomponent systems were studied. The
tetraphenylborate-selective electrode was developed for the determination of the end point in titration of
sodium tetraphenylborate solution with solutions containing potassium ions.
The scientific problemsolved in the thesis is the improvement of functional parameters of sensors,
based on trinuclear chromium(III) pivalates and 4,4΄-bipyridyl, by assembling in situ the electroactive
materials during the formation of membranes.
Theoretical and Application Value. It was demonstrated that the use of the synthesis of the
electroactive material in situ during the formation of the membrane increasios the life time of the anionic
potentiometric sensors, wich ones can be used for determination of the perchlorates, nitrates, thiocyanates,
salicylates, dodecylsulfates and perrhenate. The application value has been supplemented by developping a
new potentiometric titration method for the determination of the potassium contents. There have also been
proposed potentiometric methods have been applied for analysis of the ions in real systems.