Synthesis of Mn(Ⅲ) Complexes of New "Tailed" Porphyrins and Their Application as Carriers for PVC Membrane SCN-Anion-Selective Electrode

Three new 'tailed' porphyrins and their corresponding Mn(Ⅲ) metalloporphyrins were synthesized and characterized. The potentiometric response characteristics of the PVC membrane electrode based on the Mn(Ⅲ) complexes of the three new 'tailed' porphyrins toward SCN- have been studied.

Electrochemical Detection of the Different Species of Levofloxacin Using PVC,Carbon Paste and Screen‑Printed Electrodes:Effect of pH

The zwitterionic compound,levofloxacin,was determined for the first time at different pH values in pure samples,pharmaceutical preparations and spiked serum and urine samples.Different types of potentiometric sensors including poly(vinyl chloride)membrane electrode,carbon paste electrode and screen printed electrode,containing the ion pair levofloxaciniumphosphomolybdate as the electroactaive species,were used for this purpose.The effect of pH is the key factor in determining the ratio of the different species that can exist in the medium(zwitterionic,monocationic,dicationic,anionic and neutral),and so it is the controller of the electrochemical performance.The different sensors were fully characterized and optimized in terms of composition,pH effect,selectivity,response and lifetimes.The different sensors showed reliable reversibility and could be utilized for the determination of the drug in real spiked physiological fluids with reliable recovery values.

A novel Ce(Ⅳ)ion-selective polyvinyl chloride membrane electrode based on HDEHP and HEH/EHP

A novel Ce（Ⅳ） ion-selective polyvinyl chloride（PVC） membrane electrode based on HDEHP and HEH/EHP as ionophore was successfully prepared. The factors affecting the response of Ce（Ⅳ） ion were investigated, such as membrane composition, internal solution, concentration of SO_4^（2–）, and acidity in test solution. The best performance was obtained using the membrane with PVC：DBP：HDEHP：HEH/EHP：OA mass ratio of 75：175：5：5：5. The proposed electrode exhibited a Nernstian slope of 30.44 mV/decade for Ce（Ⅳ） ion over a linear concentration range of 1×10^（–5）–1×10^（–1） mol/L with the detection limit of 9.0×10^（-6） mol/L. The electrode showed stable response within the SO_4^（2–） concentration range of 0.1–1 mol/L and the acidity range of 0.25–1.2 mol/L H＋. The proposed electrode showed high selectivity for Ce（Ⅳ） over a wide variety of interfering ions and a fast response time. It was used as an indicator in the potentiometric titration of Ce（Ⅳ） solution with H_2O_2 solution, and could also be used for the determination of Ce（Ⅳ） in real Ce（Ⅳ）-containing aqueous samples.

Thiocyanate ion selective electrode based on bis(N-3-methylphenyl salicylidenaminato)copper(Ⅱ) ionophore

In this work a PVC membrane electrode based on bis（N-3-methyl phenyl salicylidenaminato）copper（II）as ionophore was prepared.The electrode was tested by inorganic anions and showed good selectivity for thiocyanate ion.This sensor showed Nerstian behavior with a slope of a-59.3 mV per decade at 25℃.The proposed electrode exhibited a wide linear range from 1.0 × 10^-6 mol/L to 1.0× 10^-1 mol/L with a detection limit of 5.0×10^-7 mol/L.The electrode response was independent of pH in the range of 4.0-10.0.The response time is about 9-21s,and the electrode can be used for over 60 days without considerable deterioration.The prepared sensor was applied as an indicator electrode in potentiometric titration of SCN^- with Ag^＋ ion and to determine the thiocyanate in samples of urine and saliva.

Development of new potentiometric sensors for the determination of proguanil hydrochloride in serum and urine

Potentiometric electrodes were developed for the rapid determination of proguanil hydrochloride in pure samples, pharmaceutical preparations and spiked serum and urine samples using PVC membrane,screen printed（SPE）, coated wired（CWE）, carbon paste（CPE） and modified carbon paste（MCPE）electrodes based on the ion-exchanger of proguanil with phosphotungestic acid（Pr-PT） as a chemical modifier. The prepared electrodes showed Nernestian slopes of 59.7, 58.1, 58.5, 58.5 and 57.0 for the PVC,SPE, CWE, CPE and MCPE for the proguanil ions in a wide concentration range of 1.0 ＊ 10^-5–1.0 ＊ 10^-2mol L^-1 at 25°C with detection limits of 7.94 ＊ 10^-6, 1.0 ＊ 10^-5, 1.0 ＊ 10^-6, 7.07 ＊ 10^-6 and 2.5 ＊ 10^-6 mol L^-1, respectively. The prepared electrodes exhibited high proguanil selectivity in relation to several inorganic ions and sugars and they could be successfully utilized for its determination in pure solutions, pharmaceutical preparations and serum and urine samples using the direct potentiometry and standard addition methods with very good recovery values.