An overview of potentiometric sensors that are capable of detecting toxic heavy metal ions in environmental samples is presented and discussed. Notwithstanding the tremendous work performed so far,...

Electrochemical Analysis of Some Toxic Metals by Ion–Selective Electrodes

A new procedure for the determination of selectivity coefficients of neutral carrier-based cation-selective electrodes is established that avoids exposure to the preferred ion prior to the measurement of discriminated ions. The method is, therefore, unbiased by the presence of preferred ions in the membrane that otherwise could mask the response to discriminated ion solutions. It is generally applicable as long as a series of considerations are met and can only be applied once for a given membrane. Careful studies with a series of sodium-, silver-, and calcium-selective electrodes reveal that Nernstian response slopes can now be obtained for even highly discriminated cations. Specifically, a 1,3-bridged calix[4]arene derivative as introduced by Yamamoto and Shinkai indeed yields an extraordinary sodium selectivity of log = −4.9, with potassium showing Nernst response as well. Analogous measurements with two different silver carriers, a bisthioether-functionalized calix[4]arene and methylenebis(diisobutyld...

Determination of Unbiased Selectivity Coefficients of Neutral Carrier-Based Cation-Selective Electrodes

A new poly(vinyl chloride) membrane sensor for Pb(II) ions based on N , N ′-dibenzyl-1,4,10,13-tetraoxa-7,16-diazacyclooctadecane ( I ) as an ionophore was prepared. The sensor exhibits a Nernstian response for lead ions over a wide concentration range of 8.2 × 10 −6 to 1.0 × 10 −1  M with a slope of 30.0 ± 0.1 mV/decade of activity. It has a fast response time of about 10 s and can be used for at least 3 months without any divergence in potential. The electrode can be used in the pH range 2.0–6.8. The proposed sensor shows fairly good discriminating ability towards lead ions in comparison with some alkali, alkaline earth, transition and heavy metal ions. It was successfully applied for the direct determination of Pb(II) ions in solution and as an indicator electrode in potentiometric titration of lead ions with EDTA.

PVC-based membranes of N,N' -dibenzyl -1,4,10,13 -tetraoxa -7,16 -diazacyclooctadecane as Pb(II)-selective sensor

This article reviews recent advances in the field of potentiometric solvent polymeric membrane electrodes. These sensors have found widespread applications in a variety of fields, especially in the area of clinical diagnostics. Emphasis is given on the discussion of the theoretical and practical limits of ionophore-based ion-selective electrodes, with a special focus on electrode sensitivities, characterization of selectivities and dramatic improvements in detection limits. Advances in ionophore design and in the underlying model assumptions are also discussed. It is shown that a multitude of exciting new research possibilities have recently emerged in this well—established field.

Polymer Membrane Ion-Selective Electrodes–What are the Limits?

A comparative study of Pb2+ selective sensors based on derivatized tetrapyrazole and calix[4]arene receptors

https://ris.utwente.nl/ws/files/6567069/Malinowska94lead.pdf

Lead selective electrodes based on thioamide functionalized calix[4]arenes as ionophores

https://ris.utwente.nl/ws/files/6883211/Malinowska94silver.pdf

Krzysztof Kasiura

Papers

Lead selective electrodes based on thioamide functionalized calix[4]arenes as ionophores

Silver selective electrodes based on thioether functionalized calix[4]arenes as ionophores