Construction and performance characteristics of chemically modified carbon paste electrodes for the selective determination of Co(II) ions in water samples

Design and construction of an electrochemical sensor for the determination of cerium(iii) ions in petroleum water samples based on a Schiff base-carbon nanotube as an ionophore

A carbon paste sensor (CPE) and screen-printed sensor (SPE) for Ce(iii)-selective determination were prepared using a 2,6-pyridine dicarbomethine-triethylene tetraamine macrocyclic Schiff base ligand (PDCTETA) and multi-walled carbon nanotubes (MWCNTs) as good sensing materials. With respect to most common cations, such as alkali, alkaline earth, transition, and heavy metal ions, the electrodes display high selectivity for the Ce(iii) ion. The sensors respond to Ce(iii) ions in a linear range of 1 × 10⁻⁷ to 1 × 10⁻¹ and 1 × 10⁻⁸ to 1 × 10⁻¹ mol L⁻¹ with a slope of 18.96 ± 0.73 and 19.63 ± 0.51 mV per decade change in concentration with a detection limit of 1.10 × 10⁻⁸ and 5.24 × 10⁻⁹ mol L⁻¹ for CPE (sensor IV) and SPE (sensor VIII), respectively. The sensors were found to have a lifetime of 102 and 200 days. The suggested electrodes performed well throughout the pH ranges of 3.5–8.0 and 3.0–8.5, with response times of 8 and 6 seconds for sensor IV and sensor VIII, respectively. The sensors have been used to measure Ce(iii) ions in water samples from several petroleum wells. They have also been utilized as indicator electrodes in Ce(iii) ion potentiometric titrations with EDTA. The results were quite similar to those obtained by employing atomic absorption spectrometry (AAS).

A carbon paste and screen-printed sensor for Ce(iii)-selective determination were prepared using a 2,6-pyridine dicarbomethine-triethylene tetraamine macrocyclic Schiff base ligand and multi-walled carbon nanotubes as good sensing materials.

A highly sensitive, selective and renewable carbon paste electrode based on a unique acyclic diamide ionophore for the potentiometric determination of lead ions in polluted water samples

Due to the toxicity of lead(ii) to all living organisms as it destroys the central nervous system leading to circulatory system and brain disorders, the development of effective and selective lead(ii) ionophores for its detection is very important. In this work, 1,3-bis[2-(N-morpholino)acetamidophenoxy]propane (BMAPP), belonging to acyclic diamides, was applied as a highly selective lead(ii) ionophore in a carbon paste ion selective electrode for the accurate and precise determination of Pb(ii) ions even in the presence of other interfering ions. Factors affecting the electrode's response behavior were studied and optimized. Scanning electron microscopy (SEM), energy dispersive X-ray (EDX) and FT-IR spectroscopy were used for studying the morphology and response mechanism of the prepared sensor. The lipophilicity of the used ionophore, which contributes to the mechanical stability of the sensor, was studied using the contact angle measurement technique. The selectivity coefficients obtained by the separate solution method (SSM) and fixed interference method (FIM) confirmed the selectivity of the proposed sensor for Pb(ii) ions. The proposed sensor exhibited a Nernstian slope of 29.96 ± 0.34 mV per decade over a wide linear range of 5 × 10⁻⁸ to 1 × 10⁻¹ mol L⁻¹ and detection limit of 3 × 10⁻⁸ mol L⁻¹ for 2 months with a fast response time (<10 s) and working pH range (2.5–5.5). To further ensure the practical applicability of the sensor, it was successfully applied for the lead(ii) ion determination in different water samples and the obtained data showed an agreement with those obtained by atomic absorption spectroscopy. In addition, it was successfully applied for the potentiometric titration of Pb(ii) against K₂CrO₄ and Na₂SO₄.

Due to the toxicity of lead(ii) to all living organisms destroying the central nervous system and leading to circulatory system and brain disorders, the development of effective and selective lead(ii) ionophores for its detection is very important.

Fabrication of chemically and in situ modified carbon paste electrodes for the potentiometric determination of chlorpromazine HCl in pure pharmaceutical preparations, urine and serum

Newly developed modified and in situ modified carbon paste sensors were developed for the determination of chlorpromazine hydrochloride (CPZHC) in pharmaceutical formulations and biological fluids (urine and serum).