Potentiometric Determination of Prednisolone in Pharmaceutical Formulations

In this present work, a prednisolone ion selective electrode (PRED-ISE) has been developed. The electrode shows linear response towards prednisolone in the range 3.0×10−6 – 8.6×10−3 M with a detection limit of 2.5×10−6. PRED-ISE was used as an indicator electrode for the potentiometric titration of different concentrations of standard prednisolone against standardized sodium tetraphenyl borate solution and in tablets. The electrode manifests advantages of low resistance, fast response and, most importantly, good selective relativity to a variety of other cations.

Novel Aminoacridine Sensors Based on Molecularly Imprinted Hybrid Polymeric Membranes for Static and Hydrodynamic Drug Quality Control Monitoring

Novel biomimetic potentiometric ion-selective electrodes (ISEs) were fabricated and designed for the assessment of aminoacridine (ACR) based on newly synthesized imprinted polymer (MIP) membranes. Thermal polymerization of methacrylic acid (MAA) or acrylamide (AM) as function monomer, aminoacridine as a template and ethylene glycol dimethacrylate (EGDMA) as across-linker, were utilizedto give the molecular recognition part. The membranes of sensors I andII consist of MIP based MAA and AM, respectively, dispersed in a poly(vinyl chloride) membrane plasticized with dioctyl phthalate (DOP) in the ratio of 3.0 wt%, 32.2 wt% and 64.8 wt%, respectively. Sensors III and IV were similarly prepared with added 1.0 wt% tetraphenyl borate (TPB−) as an anionic discriminator. Sensors I and II exhibited near-Nernstian potential response to ACR+ with slopes of 51.2 ± 1.3 and 50.5 ± 1.4 mV/decade in a 0.01 M phosphate buffer of pH 6.0. The linear response coversthe concentration range of 5.2 × 10−6 to 1.0 × 10−3 M with a detection limit of 0.05 and 0.17 μg/mL for sensors I and II, respectively. The performance characteristics of these sensors were evaluated under static and hydrodynamic mode of operations. They were used for quality control assessment of aminoacridine in some pharmaceutical preparations and biological samples.

Gadolinium(III) Ion-Selective Electrode Based on 3-Methyl-1H-1,2,4-triazole-5-thiol

The 3-methyl-1H-1,2,4-triazole-5-thiol (MTH) was used as a suitable ionophore for fabrication of a new gadolinium(III) ion selective potentiometric sensor. Nitrobenzene (NB) was used as plasticizing solvent mediator and sodium tetraphenyl borate (NaTPB) as an anion excluder. It displays a Nernstian response (19.8± 0.4 mV/decade) in the concentration range of 1.0×10-7to 1.0×10-2M with the detection limit of 7.3×10-8M. The sensor has a very short response time (<10s) and can be used the pH range of 2.9-8.4. electrode was successfully applied as an indicator for gadolinium determination in titration with EDTA.

A polyvinylchloride-based cadmium ion-selective electrode using [Mo2(OAc)2(H2-calix[4]arene)] as an electroactive material

A highly electroactive material Mo2[(OAc)2(H2-calix[4]arene)] is used as a neutral carrier for Cd2 + ions in this paper. The membrane is fabricated by using ionophore [Mo2(OAc)2(H2-calix[4]arene)]:poly(vinyl chloride) (PVC): dibutylphthalate(DBP):sodium tetraphenyl borate (NaTPB) in the ratio of 40:300:470:5 respectively and tetrahydrofuran (THF) used as a solvent. The membrane electrode performed in the concentration range of 9.9 × 10−8–1.0 × 10−1 M (2.34 × 10−5–23.64 mg/mL) having the Nernstian slope of 30.0±1.0 mV and the best detection limit was observed at 9.8 × 10−8 M (2.31 × 10−5 mg/mL). The proposed membrane electrode has the response time of 12 s and a useful working pH range of 1.0–7.0, and used over a period of 10 months and work satisfactorily in the test solution having 30% (v/v) non-aqueous content. Electrode sensor has distinguishable ability for Cd2 + ion with regard to several alkali, alkaline earth, transition and heavy metal ions. It was used in direct potentiometry as an indicator electrode, in the potentiometric titration of 10−3 M Cd2 + solution against 10−2 M of ethylenediaminetetraacetic acid (EDTA).

Conductometric Studies of Tetraphenyl Arsonium Chloride and Sodium Tetraphenyl Borate in Different Nonaqueous Media

The possibility of ion-pair formation of Ph