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Jonoselektywne sensory potencjometryczne i optyczne : podobne materiały konstrukcyjne, różne możliwości analityczne

Michalska A., Maksymiuk K.

Wiadomości Chemiczne

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2015

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[Z] 69, 9-10

687--699

EN

Ion-selective electrodes are a routine tool of chemical analysis, characterized by beneficial analytical parameters, simple operation principle and low apparatus cost. In this group of sensors particularly advantageous are those with plastified poly- (vinyl chloride) based membranes, containing ionophore – interacting selectively with some cations [1]. From the practical point of view all-solid-state constructions became very useful. However, in this case, a solid contact should be added between the substrate electrode and the membrane, enabling reversible charge transfer on the electrode / solid contact and solid contact / membrane interfaces. On the other hand, an advantageous alternative for membrane material, instead of poly(vinyl chloride), are polyacrylates which can be easily obtained by photopolymerization and provide lower detection limits due to lower ion mobility in the membrane. Membranes of similar composition (containing ionophore) can be also applied in ion-selective optodes, where a solid contact is not needed, but additional membrane component is a dye (chromoionophore) of different colours of the protonated and deprotonated forms. Such optodes can be also obtained as microspheres, thus they can be introduced into a medium of low volume, e.g. living cells. The next step towards sensitivity increase and miniaturization is recording fluorescence intensity instead of absorbance, by using appropriate fluorophores, e.g. pyrene, and production of nanosensors, e.g. as micelles obtained from cross-linked alternative polymers. Appropriate modification of the surface phase of such nanosensors, affecting the permeability of analyte ions into the nanospheres, enables tailoring of the shape of analytical characteristics – from sigmoidal (high sensitivity, narrow linear response range) to linear dependence of the signal on logarithm of analyte concentration (low sensitivity, but wide linear response range).

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Elektrody jonoselektywne – klasyka i nowe koncepcje

Maksymiuk K., Michalska A.

Chemik

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2015

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Vol. 69, nr 7

373--382

PL

Artykuł dotyczy tendencji rozwojowych elektrod jonoselektywnych stosowanych w potencjometrii. Przedstawiono typowe rozwiązania stosowane w praktyce, a także opisano główne kierunki badań dotyczących tej grupy sensorów, związanych zarówno z uproszczeniami konstrukcji, jak i poprawą parametrów analitycznych. Scharakteryzowano też nowe możliwości analityczne uzyskiwane dla takich elektrod w warunkach polaryzacji prądowej.

EN

The article concerns trends in development of ion-selective electrodes used in potentiomeric analysis, it shows typical practical solutions and describes main trends of research concerning this group of sensors, oriented both to construction simplification and improvement of analytical parameters. New analytical advantages, achieved under conditions of galvanostatic polarization, were also described.

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Polyaniline based dual system for potentiometric or UV-VIS spectrophotometric alkaline phosphatase detection

Malinowski P., Michalska A., Maksymiuk K.

Chemia Analityczna

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2009

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Vol. 54, No. 3

415-425

EN

A simple disposable conducting polymer - polyaniline based system for the alkaline phos- 1 phatase activity determination either in potentiometric or UV-VIS spectrophotometric setup is described. The conducting polymer was placed on a plastic polyacetate support by disper-; sing polyaniline nanoparticles. The detection method used is based on the enzymatic hydrolysis of monofluorophosphate which leads to a decrease of sample pH and finally results in a measurable change in the polyaniline electrode potential or the absorption spectra of the polymer. Both techniques offer similar sensitivity, but for the potentiometric mode a lower detection limit was obtained; it was close to 30 U L-1 (below 1 mgL-1).

PL

Opisano proste czujniki jednorazowego użytku, wykorzystujące polimer przewodzący - polianilinę, umożliwiające oznaczanie fosfatazy alkalicznej techniką potencjometrii i spektrofotometrii UV-VIS. Polimer przewodzący naniesiono z zawiesiny nanocząstek polianiliny na podłoże z folii polioctanowej. Metoda detekcji wykorzystuje enzymatyczną hydrolizę anionów monofluorofosforanowych, prowadzącą do obniżenia pH i w rezultacie do mierzalnej zmiany potencjału elektrody polianilinowej lub zmiany widma absorpcyjnego polimeru. Obie techniki zapewniaj ą podobną czułość, lecz dla metody potencjometrycznej uzyskano niższą granicę wykrywalności, bliską 30 UL-1 (poniżej l mgL-1).

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Electrochem ical Properties of Poly(3,4-ethylenedioxythiophene) Films in the Presence of Surfactants

Ocypa M., Michalska A., Maksymiuk K.

Polish Journal of Chemistry

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2008

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Vol. 82, nr 7

1463-1463

EN

Electrochemical properties of anion- and cation-exchanging conducting polymer: poly(3,4-ethylenedioxythiophene) films, doped by nitrate (PEDOT(NO3) or poly(4-styrenesulfonate) ions (PEDOT(PSS)), were stud ied in NaCl so lu tions con tain ing surfactants: an ionic (sodium dodecylbenzenesulfonate, NaDBS), cationic (hexa decyl - trimethylammonium chlo ride, RNCl) and non-ionic (Triton X 100). Voltammetric experiments revealed significant influence of surfactant only for PEDOT(NO3) in the presence of NaDBS, resulting from inter actions between anion-exchanging polymer and anionic surfactant. Impedance spectroscopy studies exhibited inhib iting influence of surfactant ions reversibly retained on the polymer/solution inter face on the rate of interfacial ion transfer, with no significant decrease of charge storing capability (redox capacitance). The influence of surfactants on analytical applicability of PEDOT as a receptor membrane for potentiometric ion sensors was discussed.

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Interfering influence of redox reactants on potentiometric responses of electrodes with conducting polymer films

Michalska A., Nadrzycka U., Maksymiuk K.

Chemia Analityczna

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2006

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Vol. 51, No. 6

923-938

EN

Conducting polymer (CP) films, used as ion-sensing membranes under open-circuit potcn-tiometric conditions, are highly sensitive towards redox interferents. u h ich seriously limit their analytical application. The factors affecting potential transients upon addition of redox reactant. as well as stable potentiometric responses in the presence of selected model redox reactants have been considered. The role of polymer redox capacitance and charge transfer kinetics has been studied. Theoretical predictions and experimental results obtained for polypyrrole, poly (N-me thylpyrrole), and poly(3,4-ethylenedioxythiophene) (PEDOT) in the presence of Fe(CN)63-/4- confirm a crucial role of spontaneous charging and discharging processes of CP films (e.g. polymer oxidation by dissolved oxygen, or deprotonation) for redox sensitivity. An experimental protocol utilising polarized electrode potentiometry has been developed in order to determine charging/discharging currents of the polymer in the absence and presence of added redox reactants. Polymers characterized by a significant charging/discharging rate (e.g. polypyrrole doped with perchloratc ions) have been found more resistant towards redox interferences than more stable polymers (e.g. PEDOT) with low-rate charging/discharging. This effect can be of a key importance not only for the CP-based ion-sensitive membranes, but also for conducting polymers used as ion-lo-elec-tron transducers (solid contacts) in all-solid-state ion-sclectivc electrodes.

PL

Warstwy polimerów przewodzących, stosowane jako membrany jonoczułe w warunkach potencjometry cznych, sąbardzo podatne na wpływ interferentów redoks, silnie ograniczający ich zastosowania analityczne. W pracy rozpatrywano c/.ynniki wpływające zarówno na zmiany potencjału w czasie po dodaniu reagenta redoks, jak i stabilne odpowiedzi notencjo-metryczne rejestrowane w obecności wybranych modelowych reagentów redoks. Dyskutowano również rolę pojemności redoks polimeru oraz, kinetyki przeniesienia ładunku. Przewidywania teoretyczne i wyniki eksperymentalne uzyskane dla polipiroiu, poli(N-metylopirolu) i poli(3,4-etylenodioksytiofenu) (PEDOT) w obecności układu Fe(CN)T63-/4-potwierdziły kluczową role samorzutnych procesów ładowania i rozładowania polimerów przewodzących (jak np. utlenianie polimeru tlenem z roztworu lub dcprotonowanie) dla czułości redoks. Opracowano procedurę eksperymentalną, wykorzystującą potencjomctrię z elektrodą polaryzowaną, w celu wyznaczania prądówzwiązanych z lądowaniem/rozładowaniem polimeru w nieobecności i obecności dodanego reagenta redoks. Wykazano, że polimery charakteryzujące się dużą szybkością procesu lądowania/rozładowani a {jak polipirol domieszkowany jonami chloranowymi(VH)) są odporniejsze na interferencje redoks niż bardziej trwale polimery (jak np. PEDOT) charakteryzujące się małą szybkością ładowania/rozładowania. Efekt ten ma kluczowe znaczenie nie tylko dla polimerów przewodzących pełniących role membrany jonoczułej, ale też dla polimerów stosowanych jako przetworniki jonowo-elektronowe (stale kontakty) w elektrodach jonoselektywnych pozbawionych roztworu wewnętrznego.

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Studies on Spontaneous Discharge of Oxidized Polypyrrole and Poly(N-methylpyrrole)

Dumańska J., Maksymiuk K.

Polish Journal of Chemistry

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2004

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Vol. 78 / nr 9

1477-1491

EN

Spontaneous processes of charging/discharging of conducting polymers affect analytical characteristics of potentiometric sensors using conducting polymer films as ion sensitive membranes (detection limit, selectivity, sensitivity to redox interferences). These effects also contribute to undesirable loss of charge accumulated in the polymer phase used in charge storing devices. For polypyrrole and its derivatives the charging process is mainly related to oxidation by oxygen or other oxidants present in solution. On the other hand, the nature of the discharge process of oxidized polymer is still not quite clear. This work is oriented towards revealing the nature of the discharge reaction of polypyrrole and poly(N-methylpyrrole). The significance of spontaneous processes, especially for analytical characteristic of potentiometric sensors based on conducting polymers, is highlighted. Therefore, the effect of electrolyte concentration, solution acidity, influence of oxygen, conditioning time and medium was studied. The results of potentiometric and coulometric studies support the thesis that the discharge process is related to the polymer deprotonation; its rate is affected by pre-polarization of the electrode and conditioning of the polymer film.

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Olimpiada chemiczna

Michalska A., Maksymiuk K.

Analityka : nauka i praktyka

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2004

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nr 1

53-54

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Electrochemical Properties of Cells with Conducting Polymers and Nafion Membranec

Błasiak M., Golimowski J., Maksymiuk K.

Polish Journal of Chemistry

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2001

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Vol. 75, nr 11

1729-1738

EN

Electrochemical properties of cells, comprising electronically- and ionically-conducting polymers, were studied using open sandwich electrode systems of cation exchanging polypyrrole or poly(N-methylpyrrole) doped by poly(4-styrenesulphonate) ions or Nafion (PPy(PSS) and PMPy(PSS) or PPy(Nafion) and PMPy(Nafion) respectively). The electrolyte/separator used was Nafion 117 membrane. These cells were characterized by a stable open circuit voltage (in the absence of oxygen), possibility of repeated charge/ discharge and capacity of order 10 C/g of polymeric materials. Therefore, these systems are promising for practical applications in all plastic battery construction using conducting polymers.

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Electrochemical Studies of Trilayers of Conducting Polymers

Żabczyńska K., Maksymiuk K.

Polish Journal of Chemistry

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1999

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Vol. 73, nr 9

1523-1534

EN

Trilayer systems of conducting polymers consecutively coated on electrodes were studied in electrolyte (1 M KCl) solutions, using voltammetric and additionally chronoamperometric techniques. The trilayers were composed of polypyrrole doped with poly(4-styrenesulfonate) (PPy(PSS)) or perchlorate ions (PPy) as well as of poly(N-methylpyrrole) doped with perchlorates (PMPy).