Solid-State Thin-Film Sensors Based on Chalcogenide Materials Obtained by Planar Technology and Pulsed Laser Deposition

Methods of silicon planar technology and pulsed laser deposition were applied to fabricate fully solid-state chemical sensors for determining ions of copper, lead, cadmium, thallium, and also sulfide and chloride ions on the basis of thin chalcogenide films as ion-sensitive membranes.     

Electronic tongue for quality assessment of ethanol, vodka and eau-de-vie

Rapid quality assessment of alcoholic beverages, including brand identification and detection of products of unacceptable quality or counterfeits is an important practical task. In the present work the multisensor electronic tongue system (ET), based on array of potentiometric chemical sensors was applied to recognition and classification of spirits such as vodka and ethanol used for vodka production and also for eau-de-vie in cognac production. The ET system was capable of detecting presence of contaminant substances in vodka in concentrations exceeding allowed levels as well as of distinguishing vodka complying and not complying with state quality standards. Ten brands of vodka produced at the same distillery using water and ethanol of different purity and various taste additives were discriminated using the instrument. The ET could distinguish synthetic and alimentary grain ethanol as well as alimentary ethanol of different grades (i.e. different degree of purification). A feasibility study was run on several eau-de-vie samples, which included fresh and aged eau-de-vie as well as samples produced using different distillation technology and samples kept in contact with different kinds of oak. The electronic tongue showed a promise as an analytical instrument for rapid quality assessment of spirits.     

New Sensory Materials Based on Chalcogenide Glasses Containing Zinc,Cadmium, and Manganese Sulfides

New chalcogenide glasses of the system 0.5AgI-(0.5 - x)Sb₂S_3-x MS containing cadmium, man- ganese, and zinc sulfides were obtained. The high purity of these materials and their glassy state were proved by X-ray analysis and X-ray fluorescence energy-dispersive spectroscopy. The impedance of the glasses obtained was measured within a wide range of frequencies, and the dependences of the conductivity on the composition of glasses were studied. New potentiometric sensors based the new glasses were developed, and an electrochemical experiment was carried out.     

Chalcogenide glass chemical sensors: Research and analytical applications

The paper is devoted to research and development in the field of chalcogenide glass chemical sensors for determination of heavy metal ions in solution. The overview of the solid-state scientific approach and research design of the sensing materials is followed by the original results of the analytical application of the chalcogenide glass sensors for laboratory analysis, industrial control and environmental monitoring.     

Generation of characteristic profiles of steroid hormones by reversed-phase HPLC

A method for the determination of steroid hormones by reversed-phase HPLC has been applied to the analysis of biological fluids from healthy individuals and patients with endocrine systems diseases. The obtained chromatographic profiles were processed by the method of principal component analysis and method of soft independent modeling of class analogy. The principle possibility of using the results of chemometric processing of the chromatographic profiles as an additional diagnostic criterion for the treatment of some endocrine pathologies has been shown.     

Multivariate processing of atomic-force microscopy images for detection of the response of plasticized polymeric membranes

The possibility of using the atomic-force microscopy as a method for detection of the analytical signal from plasticized polymeric sensor membranes was analyzed. The surfaces of cadmium-selective membranes based on two polymeric matrices were examined. The digital images were processed with multivariate image analysis techniques. A correlation was found between the surface profile of an ion-selective membrane and the concentration of the ion in solution.     

Potentiometric and theoretical studies of the carbonate sensors based on 3-bromo-4-hexyl-5-nitrotrifluoroacetophenone

Novel carbonate ionophore, trifluoroacetophenone derivative (TFA) substituted by two acceptor substituents in the phenyl ring (3-bromo-4-hexyl-5-nitrotrifluoroacetophenone), was synthesized. Solvent polymeric membrane sensors based on this ionophore exhibited heightened selectivity to carbonate ions in the presence of the most important interfering anions. A wide range of potentiometric properties were studied and compared with those of sensors based on mono-substituted ionophores. Special attention was paid to pH dependence of sensor responses and to elaboration of appropriate conditions for carbonate analysis. A segmented-sandwich membrane method was applied for determination of the stoichiometry of ionophore-carbonate complexes, which was determined to be 1:3, and apparent complex formation constants which were 14.4 and 13.6 for DOS- and NPOE-plasticized membranes, respectively. Theoretical studies on TFA derivatives by semi-empirical (AM1 and PM3) and ab initio(6-31+G*) methods were performed, considering different types of possible ionophore-ion interactions. The formation of hydrogen bonds between carbonate and hydrated TFA was proved to be much more favourable in terms of energy compared to tetrahedral nucleophilic adducts that earlier were postulated to being formed in the membrane phase. The final conclusion on the mechanism of carbonate sensing by TFA-based solvent polymeric membrane sensors was made on the basis of computational data and detailed analysis of the literature.