نتایج جستجو برای: potentiometric
تعداد نتایج: 3023 فیلتر نتایج به سال:
New, simple and convenient potentiometric and spectrophotometric methods are described for the determination of dextromethorphan hydrobromide (DXM) in pharmaceutical preparations. The potentiometric technique is based on developing a potentiometric sensor incorporating the dextromethorphan tetrakis(p-chlorophenyl)borate ion-pair complex as an electroactive species in a plasticized PVC matrix me...
An improved protamine-sensitive electrode based on a polymeric membrane doped with the charged ion exchanger dinonylnaphthalenesulfonate (DNNS) is used for monitoring heparin concentrations in whole blood. The electrode exhibits significant nonequilibrium potentiometric response to polycationic protamine over the concentration range of 0.5-20 mg/L in undiluted whole-blood samples. The sensor ca...
In this work, we are presenting an iron ion (Fe 3+ ) potentiometric sensor based on functionalized ZnO nanorods with selective ionophore (18 crown 6). Zinc oxide nanorods with a diameter of about 100 to 150 nm and 1μm in length were grown on gold coated glass. The selective Fe 3+ ionophore sensor with highly aligned ZnO nanorods has given high sensitivity, acceptable selectivity, reproducibilit...
This paper gives an overview of the newest developments of polymeric membrane ion-selective electrodes. A short essence of the underlying theory is given, emphasizing how the electromotive force may be used to assess binding constants of the ionophore, and how the selectivity and detection limit are related to the underlying membrane processes. The recent developments in lowering the detection ...
Potentiometric chloride sensors were fabricated by electrochemically chloridizing the surface of screen printed silver electrodes using amperostatic coulometry or asymmetric square wave voltammetry. In the case of coulometric chloridization, the effect of different chloride ion sources was also investigated. The response to chloride ions by each type of sensor was determined by measuring their ...
1 A theoretical treatment of potentiometric data is applied to calculate coextraction 2 constants (K IA) for three potassium salts from water into a liquid nitrobenzene phase. 3 The experiment involves treating nitrobenzene as a membrane and contacting it with 4 two aqueous solutions of different ion activities. In the presence of either a cation or 5 anion exchanger, the ratio of activities of...
This paper describes the design and fabrication of ion-sensing electrochemical paper-based analytical devices (EPADs) in which a miniaturized paper reference electrode is integrated with a small ion-selective paper electrode (ISPE) for potentiometric measurements. Ion-sensing EPADs use printed wax barriers to define electrochemical sample and reference zones. Single-layer EPADs for sensing of c...
The basis of potentiometry is the Nernst equation, which relates the concentration of electroactive species at the surface of an electrode (C) to the potential of that electrode (E); that is, for the reaction O + e = R where E is the formal redox potential of the electron transfer reaction. In a potentiometry experiment, the open-circuit potential (i.e., there is no measurable current through t...
NEW, RAPID, SENSITIVE, AND ACCURATE method for determination of chloride was recently developed and described (1) which eliminates many difficulties inhereiit in other procedures. This method, called the precision null-point potentiometric method, can be applied for accurate determinations of chloride over a wide concentration range, as low as 10 M. and as high as necessary if the sample can be...
Ion-selective electrode (ISE) based potentiometric gas sensors have shown to be promising analytical tools for detection of chemical vapors. However, such sensors are only capable of detecting those vapors which can be converted into ionic species in solution. This paper describes for the first time a polymer membrane ISE based potentiometric sensing system for sensitive and selective determina...
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