Lifetime of neutral carrier based ion-selective liquid-membrane electrodes

Oesch, U.; Simon, W.

doi:10.1021/ac50054a024

Cited by 321 publications

(169 citation statements)

References 28 publications

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“…1). In the case of plasticized polymer membranes used for conventional ISEs, the diffusion coefficient of primary ions in the membrane phase is lower than in aqueous solutions by at least two orders of magnitude [37][38][39][40]. Thus, the membrane resistance is high and the value of I o comparatively low.…”

Section: Resultsmentioning

confidence: 99%

Current response of ion-selective solvent polymeric membranes at controlled potential

Sutter

Morf

Rooij

et al. 2004

Journal of Electroanalytical Chemistry

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From electrochemical measurements at the interface of two immiscible electrolytes, the current at controlled potential is usually a linear function of the ion concentration in the aqueous phase. Surprisingly, a linear relationship between the current and the logarithm of the sample ion activity is found for corresponding measurements on ion-selective electrode membranes. Here, a theoretical explanation for the apparent contradiction between the behavior of the two kinds of system is given. Experimental results obtained with conventional ion-selective PVC membranes as well as with membranes based on PVC free membrane matrices are presented.

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Section: Resultsmentioning

confidence: 99%

Current response of ion-selective solvent polymeric membranes at controlled potential

Sutter

Morf

Rooij

et al. 2004

Journal of Electroanalytical Chemistry

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“…This ratio is expected to change the diffusion coefficient of the membrane [23][24] and thus the overall potentiometric performance. The amount of PVC introduced in the membrane was 136, 180 or 270 mg (Table 1).…”

Section: Effect Of the Selective Membrane Compositionmentioning

confidence: 99%

New and low cost plastic membrane electrode with low detection limits for sulfadimethoxine determination in aquaculture waters

Almeida

Montenegro

Sales

2013

Journal of Electroanalytical Chemistry

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A B S T R A C TSulfadimethoxine (SDM) is one of the drugs, often used in the aquaculture sector to prevent the spread of disease in freshwater fish aquaculture. Its spread through the soil and surface water can contribute to an increase in bacterial resistance. It is therefore important to control this product in the environment. This work proposes a simple and low-cost potentiometric device to monitor the levels of SDM in aquaculture waters, thus avoiding its unnecessary release throughout the environment. The device combines a micro-pipette tip with a PVC membrane selective to SDM, prepared from an appropriate cocktail, and an inner reference solution. The membrane includes 1% of a porphyrin derivative acting as ionophore and a small amount of a lipophilic cationic additive (corresponding to 0.2% in molar ratio). The composition of the inner solution was optimized with regard to the kind and/or concentration of primary ion, chelating agent and/or a specific interfering charged species, in different concentration ranges. Electrodes con-structed with inner reference solutions of 1 x 10 -8 mol/L SDM and 1 x 10 -4 mol/L chromate ion showed the best analytical features. Near-Nernstian response was obtained with slopes of -54.1 mV/decade, an extraordinary detection limit of 7.5 ng/mL (2.4 x 10 -8 mol/L) when compared with other electrodes of the same type. The reproducibility, stability and response time are good and even better than those obtained by liquid contact ISEs.Recovery values of 98.9% were obtained from the analysis of aquaculture water samples.

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“…The same effect appears after working with the electrode(s) for a long time. The regeneration of the electrode(s) was tried simply by reformation of the ion-pair on the external gel layer of membrane [23]. The regeneration of the SIM membrane was successfully achieved by soaking the exhausted electrode(s) for 24 h in a solution that was 1.0 x 10 -2 mol L -1 phophotungstic or phosphomolybdic acid, followed by soaking for 3 h in 1.0 x 10 -2 mol L -1 SIM solution.…”

Section: Effect Of Soaking Time and Regeneration Of The Electrodementioning

confidence: 99%

Electrochemical Sensors for Direct Determination of Simvastatin in Pharmaceutical Formulations and Biological Fluids

Alarfaj

Aly

El‐Tohamy

2012

J. Chil. Chem. Soc.

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The construction and performance characteristics of simvastatin (SIM) selective electrodes were developed. Three types of electrodes: plastic membrane I, coated wire II, and coated graphite rod III were constructed based on the incorporation of simvastatin with phosphotungstic (PTA) or phosphomolybdic (PMA) acids and mixed ion pair (PTA/PMA) for the three electrodes, respectively. The influence of membrane composition, kind of plasticizer, type of ion-pair, pH of the test solution, soaking time, and foreign ions on the electrodes was investigated. The electrodes showed a Nernstain response with a mean calibration graph slope of 56.24±0.43, 55.44±0.14 and 58.93±0.34 mV decade -1 at 25ºC over simvastatin concentration range from 1.0 x 10 -6 -5.0 x 10 -2 , 9.0 x 10 -6 -5.0 x 10 -3 and 9.0 x 10 -7 -1.0 x 10 -2 mol L -1 , with detection limit of 5.0 x 10 -7 , 3.9 x 10 -6 and 3.2 x 10 -7 mol L -1 for electrode I, II and III, respectively. The pH range for the proposed electrodes was 4-7. The influence of possible interfering species such as common inorganic cations, many sugars, amino acids and a pharmacologically related drug 'ezetimibe' was studied. Statistical student's t-test and F test showed insignificant systematic error between proposed and official methods.

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Lifetime of neutral carrier based ion-selective liquid-membrane electrodes

Cited by 321 publications

References 28 publications

Current response of ion-selective solvent polymeric membranes at controlled potential

Current response of ion-selective solvent polymeric membranes at controlled potential

New and low cost plastic membrane electrode with low detection limits for sulfadimethoxine determination in aquaculture waters

Electrochemical Sensors for Direct Determination of Simvastatin in Pharmaceutical Formulations and Biological Fluids

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