Fluoride-selective polymeric membrane electrodes based on Zr(IV)- and Al(III)-salen ionophores of various structures

Fabrication and Applications of Potentiometric Membrane Sensors Based on γ-Cyclodextrin and Calixarene as Ionophores for the Determination of a Histamine H1-Receptor Antagonist: Fexofenadine

Supramolecular fexofenadine sensors have been constructed. Although noncovalent intermolecular and intramolecular interactions, which are far weaker than covalent contacts, are the main focus of supramolecular chemistry, they can be used to create sensors with an exceptional affinity for a target analyte. The objective of the current research study is to adapt two PVC membrane sensors into an electrochemical approach for the dosage form determination of histamine H1-receptor antagonists: fexofenadine. The general performance characteristics of two new modified potentiometric membrane sensors responsive to fexofenadine hydrochloride were established. The technique was based on the employment of γ-cyclodextrin (CD) (sensor 1), 4-tert-butylcalix[8]arene (calixarene) (sensor 2) as an ionophore, potassium tetrakis (4-chlorophenyl) borate (KTpClPB) as an ion additive, and (o-NPOE) as a plasticizer for sensors 1 and 2. The sensors showed fast responses over a wide fexofenadine concentration range (1 × 10^-2 to 4.5 (4.7) × 10^-6 M), with detection limits of 1.3 × 10^-6 M and 1.4 × 10^-6 M for sensors 1 and 2, respectively, in the pH range of 2-8. The tested sensors exhibit the fexofenadine near-Nernstian cationic response at 56 and 58 mV/decade for sensors 1 and 2, respectively. The sensors exhibit good stability, fast response times, accuracy, precision, and longer life for fexofenadine. Throughout the day and between days, the sensors exhibit good recovery and low relative standard deviations. Fexofenadine in its pure, dose form has been identified with success using the modified sensors. The sensors were employed as end-point indications for the titration of fexofenadine with NaTPB.

Portable fluoride-selective electrode as signal transducer for sensitive and selective detection of trace antibiotics in complex samples

Ion-selective electrodes (ISE) can rapidly, sensitively detect their corresponding ions and are suitable for field testing. However, most ISE methods cannot detect other targets directly which limits their practice application. Herein, we established an aptamer-sensing platform to detect organic small molecule using a portable fluoride-selective electrode (FSE). To achieve the purpose, novel signal tags were fabricated based on nano metal-organic frameworks (NMOF) encapsulating F- and labeling aptamers. They were then immobilized on one stir-bar. Subsequently, a double stir-bars (bar-a and b) assisted target recycling strategy was designed to convert organic small molecular target to F- for signal development and amplification. The movement of tags from bar-a to b can be triggered by the analytes. After reaction, the transferred signal tags in bar-b were washed and released F- which can be measured by FSE for qualification of the target. The assay was evaluated to detect kanamycin or chloramphenicol which was employed as the representatives of organic small molecular with a low detection limit of 0.35 nmol L^-1 or 0.46 nmol L^-1, respectively. Satisfactory performance was observed in complex sample analysis of kanamycin (milk, fish, urine and serum) with a recovery of 91-108% and an RSD (n = 6) <5%. The proposed method broadens the application of traditional FSE to the detection of organic small molecule. And the employment of NMOF which has higher encapsulating capacity of F- for preparing signal tags can be extended to FSE based aptasensors.

Binding studies and anion-selective electrodes with neutral isophthalamide-based receptors

The incorporation of neutral and structurally simple isophthalamide-based receptors into plasticised polymeric membrane anion-selective electrodes has afforded devices with a good sensing ability.

Electrochemical study of ivabradine hydrochloride ion selective electrodes using different ionophores

Development of novel sensors for the determination of ivabradine hydrochloride using sulphonated calix-8-arene and cyclodextrin derivatives as neutral ionophores.

Comparative study of normal, micro- & nano-sized iron oxide effect in potentiometric determination of fluconazole in biological fluids

Three novel fluconazole (FLU) selective electrodes were investigated with di-octyl phthalate as a plasticizer in a polymeric matrix of polyvinyl chloride and 2-hydroxypropyl-β-cyclodextrin as an ionophore.