Potentiometric sensor for the indomethacin determination

A potentiometric indomethacin-selective sensor based on Rhodamine B indomethacinate ion-pair (IP) as a membrane carrier is reported. Influences of the membrane composition, pH, and possible interfering ions were investigated on the response properties of the electrode. The sensor exhibits significantly enhanced response toward indomethacinate ions over the concentration range 1 × 10^? 4 mol L^? 1 to 5 × 10^? 2 mol L^? 1 with a lower detection limit (LDL) of 3 × 10^? 5 mol L^? 1 and a slope of ? 60 mV decade^? 1. Fast and stable response, good reproducibility, long-term stability, applicability over a pH range of 6–10 is demonstrated. The proposed electrode shows good discrimination of indomethacin from several inorganic and organic ions. The proposed sensor has been applied for the direct potentiometric determination of indomethacin in pharmaceutical preparations.     

Quaternary thiospinel CuCrTiS4 as an electroactive material for copper(II)-sensitive and selective electrode

CuCrTiS₄ was obtained by solid-state synthesis methods. The crystal structure of the quaternary phase was investigated by X-ray powder method and is described in the thiospinel structure (space group Fd¯3m) with the lattice parameter а = 0,99388(1) nm. Atomic parameters were refined in the isotropic approximation (R_I = 0.0465, R_P = 0.1060). The possibility of the use of this compound as an electroactive substance in graphite-paste electrodes for the measurement of Сu²⁺ ions was investigated. The electrodes exhibit a Nernstian response towards copper (II) ions with a cationic slope. The optimal electrode composition, detection limit (6 · 10^− 7 M), selectivity coefficient for major interfering elements, рН range and practical applicability of such electrodes were established.     

Potentiometric determination of ketoprofen and piroxicam at a new PVC electrode based on ion associates of Rhodamine 6G

The characteristics, performance and application of ion-selective electrodes for ketoprofen and piroxicam ions based on Rhodamine 6G as electrode-active substances are described. These electrodes respond with sensitivities of (58.0 ± 1.0) and (57.0 ± 2.0) mV/decade over the range 1.0 × 10^? 4–1.0 × 10^? 1 and 1.0 × 10^? 4–5.0 × 10^? 2 mol/l at pH 5–9 and 6–10 and a detection limit of 6.3 × 10^? 5 and 3.2 × 10^? 5 mol/l for ketoprofen and piroxicam, respectively. The electrodes are easily constructed at a relatively low cost, have a fast response time and can be used for a period of 5 months without any considerable divergence in potential. The proposed sensor displayed good selectivity for ketoprofen and piroxicam in the presence of several substances and inorganic anions. It was used for the direct assay of ketoprofen and piroxicam in commercial pharmaceutical preparations.     

New potentiometric sensor for the determination of iodine species

The characteristics, performance and application of novel triiodide potentiometric sensor based on ion-pair of Rhodamine B triiodide as a membrane carrier are described. The electrode has a linear dynamic range between 1 × 10^? 6 and 1 × 10^? 1 M, with a Nernstian slope of 68 ± 1 mV pC^? 1 and detection limit of 3.9 × 10^? 7 M. Fast and stable response, good reproducibility, long-term stability, very good selectivity over a large number of common organic and inorganic anions, applicability over a pH range of 2–10 are demonstrated. The proposed sensor has been applied for potentiometric determination of some iodine species.     

The potentiometric sensor for determination of pentachlorophenol in water

A pentachlorophenolate—a sensitive device based on an ionic associate of astraphloxine pentachlorophenol has been developed. The proposed sensor possesses satisfactory electroanalytical characteristics, which makes it possible to use it in its potentiometric determination of pentachlorophenol in water.