Selective Poly Vinyl Chloride Membrane Research Articles

Thiophene-based Schiff base ligand as ionophore for Ni(II)-selective polyvinyl chloride membrane electrode

Abstract A synthesized Schiff base 2-acetylthiophene semicarbazone (3) was used for the preparation of Ni2+ selective polyvinyl chloride (PVC) membrane electrode. The prepared electrode with the optimized composition, PVC:3:sodium tetraphenylborate:di-n-butylphthalate as 33:6:3:58 exhibited a Nernstian response over the working range of 5.0 × 10−6–5.0 × 10−2 mol l−1 with a slope of 29.0 ± 0.3 mV/concentration. The electrode showed good selectivity towards Ni2+ with respect to several metal ions in the pH range of 2.5–10.0 in <15 s with a detection limit of 4.7 × 10−6 mol l−1. The electrode showed the additional benefit of working in partially nonaqueous media having up to 15% (v/v) methanol or ethanol. This electrode was also successfully applied in Ni2+ ion potentiometric titration with ethylenediaminetetraacetic acid as an indicator electrode.

Silver(I)-selective PVC membrane potentiometric sensor based on 5,10,15,20-tetra(4-pyridyl)-21H, 23H-porphine and potentiometric applications

In this study, all-solid-state contact PVC membrane silver(I)-selective sensor has been prepared and 5,10,15,20-tetra(4-pyridyl)-21H,23H-porphine used as ionophore. Optimum membrane composition; 3.5% ionophore, 59.6% Bis(2-ethylhexyl) sebacate (BEHS), 1.0% potassium tetrakis (p-chlorophenyl) borate (KTpClPB) and 35.9% polyvinyl chloride (PVC). The developed silver(I)-selective sensor exhibited a linear response (E = −51,57 (−log[Ag+]) + 1690,6 and R2 = 0,9986) in the varying concentration range of 1.0 × 10−1 to 1.0 × 10−5 mol L−1 silver ions. The limit of detection of the sensor was calculated as 1.9 × 10−6 mol L−1. The silver(I)-selective sensor exhibited good selectivity towards some alkali, alkali earth and heavy metal ions. The sensor can be used in the pH range from 4.0 to 10.0. The sensor has been shown to have good reusability and response time less than 8 s. The sensor was used as an indicator electrode in titrations of silver nitrate with sodium chloride solution and was successfully applied for the determination of the different water samples. In this study, all-solid-state contact PVC membrane silver(I)-selective sensor has been developed. The developed silver(I)-selective sensor exhibited a linear response in the varying concentration range of 1.0 × 10−5 to 1.0 × 10−1 mol L−1 silver ions. The sensor was successfully applied for the determination of the different real samples.

A novel silver(I)-selective PVC membrane sensor and its potentiometricapplications

Silver(I)-selective sensors were prepared from a solid-state contact polyvinyl chloride (PVC) membrane. ($Z)$-2-(2-((3-(2-hydroxyphenyl)-5-(p-tolyl)-1$H$-pyrrol-2-yl)imino)-5-(p-tolyl)-2$H$-pyrrol-3-yl)phenol was synthesized as an ionophore molecule and embedded in the silver(I)-selective PVC membrane composition. The optimum membrane composition was determined as 2.5% ionophore, 61.7% bis-(2-ethylhexyl)sebacate, 1.0% potassium tetrakis (p-chlorophenyl) borate, and 34.8% PVC. The developed sensor exhibited a linear potential change $E$ = 67.42 (-log [Ag$^{+}$]) $+$ 1152.9 and $R^{2}$ = 0.9960) in the varying concentration range of 1.0 $\times $ 10$^{-1}$ to 1.0 $\times $ 10$^{-5}$ mol L$^{-1}$ silver ions. This sensor shows a detection limit of 7.3 $\times $ 10$^{-7}$ mol L$^{-1}$. The proposed sensor showed a good potential change with high sensitivity even in a wide range of pH values (2.0-11.0). The proposed sensor had a quick electrochemical response of less than 3 s with good selectivity and repeatability. The sensor was also successfully applied in the analysis of real water samples. In real water samples prepared by standard addition method, recoveries in the range of 82.30%-95.15% were obtained.

Ion selective PVC membrane electrodes for the determination of trazodone hydrochloride in pharmaceutical formulation

The electrochemical response characteristics of poly(vinyl)chloride (PVC) based membrane electrodes for determination of trazodone hydrochloride (TZH) is described. The membranes of these electrodes consist of trazodone-phosphomolybdate (TZH-PMA) ion pair in a PVC matrix with di-butyl phosphate (DBP) or dioctyl pthalate (DOP) as a plasticizers. The influences of membranes composition, response time, pH of the test solution, and foreign ions on the electrodes performance were investigated. The electrodes exhibited mean slopes of calibration graphs of 56.25 and 58.55 mV per decade of trazodone concentration at 25.0 °C for the optimum electrode 6.0% with DBP (electrode I) and 10.0% with DOP (electrode II) plasticizers respectively. The electrodes were successfully applied to the determination of trazodone hydrochloride and its pharmaceutical preparation with good precision and accuracy.

Fabrication of an iron(III)-selective PVC membrane sensor based on a bis-bidentate Schiff base ionophore

A Fe3+ ion-selective membrane sensor was fabricated from polyvinyl chloride (PVC) matrix membrane containing bis-bidentate Schiff base (BBS) as a neutral carrier, sodium tetraphenyl borate (NaTPB) as anionic excluder, and o-nitrophenyloctyl ether (NPOE) as a plasticizing solvent mediator. The effects of the membrane composition, pH, and additive anionic influence on the response properties were investigated. The best performance was obtained with a membrane containing 32% PVC, 62.5% NPOE, 3% BBS, and 2.5% NaTPB. The electrode shows a Nernstian behavior (slope of 19.3 ± 0.6) over a very wide iron ion concentration range (1.0 × 10−7–1.0 × 10−2 M) and has a low detection limit (7.4 × 10−8 M). The potentiometric response of the sensor is independent of pH of the solution in the pH range 1.9–5.1. The proposed sensor has a very low response time (<15 s) and a good selectivity relative to a wide variety of other metal ions including common alkali, alkaline earth, heavy, and transition metal ions. The electrode can be used for at least 60 days without any considerable divergence in potentials. The proposed sensor was successfully applied as an indicator electrode for the potentiometric titration of 1.0 × 10−2 M Fe3+ ions with a 1.0 × 10−4 M EDTA and the direct determination of Fe3+ in mineral water and wastewater samples.