Browsing by Author "Martin, Mariana"

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Nitrate-selective electrodes based on the trinuclear chromium(III) pivalates [Articol]
(Institute of Chemistry of ASM, 2008) Revenco, Mihail; Martin, Mariana; Dayyih, Waell A.A.
The paper describes the analytical potentialities of the trinuclear chromium(III) complexes as potentiometric ionophores for the construction of electrodes sensitive to the presence of nitrate anion. The electroactive material containing 4,4’-bipyridil was synthesized in situ. The membrane was prepared using dioctylphthalate as a solvent mediator and poly (vinyl chloride) as a polymeric matrix. The electrodes presented a slope of 56 mV/decade, a low limit of detection (3,2.10-6 mol/l), an adequate lifetime (4 months), and suitable selectivity characteristics when compared with other nitrate electrodes. The good parameters of this electrode made possible its application to the determination of nitrate in different types of fertilizers.
Nitrate-selective electrodes based on the trinuclear chromium(III) pivalates [Articol]
(Academia de Știinițe a Moldovei, 2008) Revenco, Mihail; Martin, Mariana; Dayyih, Waell A.A.
The paper describes the analytical potentialities of the trinuclear chromium(III) complexes as potentiometric ionophores for the construction of electrodes sensitive to the presence of nitrate anion. The electroactive material containing 4,4’-bipyridil was synthesized in situ. The membrane was prepared using dioctylphthalate as a solvent mediator and poly (vinyl chloride) as a polymeric matrix. The electrodes presented a slope of 56 mV/decade, a low limit of detection (3,2.10-6 mol/l), an adequate lifetime (4 months), and suitable selectivity characteristics when compared with other nitrate electrodes. The good parameters of this electrode made possible its application to the determination of nitrate in different types of fertilizers.
Senzor potenţiometric salicilat-senzitiv pe bază de pivalaţi trinucleari ai cromului(III) [Articol]
(CEP USM, 2008) Revenco, Mihail; Martin, Mariana; Gavriliţa, Anatolie; Dayyih, Wael Ahmad Abu
New salicylate-selective electrodes based on trinuclear chromium(III) pivalates are described. The electrodes were prepared by incorporating the ionophores into plasticized poly(vinylchloride) membranes. The electrode displays a linear –log [C7H6O3-] vs emf response over the concentration range 3,2.10-6 – 1.10-1 M in buffer solutions of pH 7, with a Nernstian slope of 56 mV/decade of salicylate concentration. The electrodes exhibit fast response times and micromolar detection limits and could be used over a wide pH range of 7 – 11. The proposed electrode was applied to determine the salicylates in real samples.
Thiocyanate ion-selective PVC membrane electrode [Articol]
(Institute of Chemistry of ASM, 2010) Revenco, Mihail; Martin, Mariana; Dayyih, Waell Abu
A potentiometric selective sensor based on trinuclear chromium(III) complex as a novel ionophore for the thiocyanate-selective electrode is reported. The sensor displays a near Nernstian slope of 57 ± 2 mV per decade, over a wide pH range 3 - 11. The working concentration range of the electrode is 1.10-5 – 1.10-1 mol/L with a detection limit of 5.10-6 mol/L. The sensor has a response time of 20 s and can be used for at least 6 months without any considerable fluctuation of the potential. The selectivity coefficients determined at using the fixed interference method indicate a good discriminating ability towards other anions. The prepared sensor was applied as an indicator electrode in the titration of thiocyanate with Ag+.
Thiocyanate ion-selective PVC membrane electrode [Articol]
(Academia de Știinițe a Moldovei, 2010) Revenco, Mihail; Martin, Mariana; Dayyih, Waell Abu
A potentiometric selective sensor based on trinuclear chromium(III) complex as a novel ionophore for the thiocyanate-selective electrode is reported. The sensor displays a near Nernstian slope of 57 ± 2 mV per decade, over a wide pH range 3 - 11. The working concentration range of the electrode is 1.10-5 – 1.10-1 mol/L with a detection limit of 5. 10-6 mol/L. The sensor has a response time of 20 s and can be used for at least 6 months without any considerable fluctuation of the potential. The selectivity coeffi cients determined at using the fi xed interference method indicate a good discriminating ability towards other anions. The prepared sensor was applied as an indicator electrode in the titration of thiocyanate with Ag+.