Novel Metronidazole Membrane Sensor Based on a 2,6‐(p‐N,N‐Dimethylaminophenyl)‐4‐Phenylthiopyrylium Perchlorate

A novel PVC‐based membrane sensor based on 2,6‐(p‐N,N‐dimethylaminophenyl)‐4‐phenylthiopyrylium perchlorate (DAPP) is described. The electrode exhibits a sub‐Nernstian response to 1‐(beta‐hydroxyethyl)‐2‐methyl‐5‐nitroimidazole (metronidazol) over a relatively wide concentration range (1.0 × 10^?1 to 1.0 × 10^?5 M) with a detection limit of 8.0 × 10^?6 M. The best performance was obtained with the membrane containing 30% poly (vinyl chloride), 50% dibutyl phthalate, 7% DAPP and 13% oleic acid. It has a fast response time (< 30 s) and can be used for at least four weeks without any major deviation. The proposed sensor revealed very good selectivity for metronidazole over a wide variety of common cations, anions and amino acids and could be used in the pH range of 6.0–7.5. It was successfully used for direct determination of metronidazole in an oral synthetic antiprotozoal as an antibacterial agent, in metronidazole tablets, and metronidazole injections and metronidazole gels.     

Fluorescence “turn-on” chemosensor for the selective detection of zinc ion based on Schiff-base derivative

N,N′-phenylenebis(salicylideaminato) (L) has been used to detect trace amounts of zinc ion in acetonitrile–water solution by fluorescence spectroscopy. The fluorescent probe undergoes fluorescent emission intensity enhancement upon binding to zinc ions in MeCN/H₂O (1:1, v/v) solution. The fluorescence enhancement of L is attributed to the 1:1 complex formation between L and Zn(II), which has been utilized as the basis for selective detection of Zn(II). The linear response range for Zn(II) covers a concentration range of 1.6 × 10^?7 to 1.0 × 10^?5 mol/L, and the detection limit is 1.5 × 10^?7 mol/L. The fluorescent probe exhibits high selectivity over other common metal ions, and the proposed fluorescent sensor was applied to determine zinc in water samples and waste water.     

Liquid membrane potentiometric sensor for determination of Fe3+ ion

Solution studies showed a selective interaction between the new synthesized ionophore, 2-[(thiophen-2-yl)methyleneamino]isoindoline-1,3-dione (TMID) and Fe(III) ion. Therefore, TMID was used as an iron selective ion-carrier in a plasticized liquid membrane sensor. The linear response range of the proposed electrode was 1.0 × 10^?6–1.0 × 10^?2 M. The Nernstian slope of 20.1 ± 0.3 mV/decade, and a detection limit of 5 × 10^?7 M was obtained. The sensor could be used in the pH range of 2.3–4.8, and the response time was about 10 s. The lifetime of the electrode was at least 7 weeks. The sensor accuracy was investigated in two ways: (i) with the potentiometric titration of a Fe³⁺ solution with EDTA and (ii) with Fe(III) monitoring in some cationic mixtures. Finally, the newly fabricated electrode was effectively applied as an indicator electrode for the direct Fe³⁺ determination in real samples.     

Ion recognition: application of symmetric and asymmetric schiff bases and their complexes for the fabrication of cationic and anionic membrane sensors to determine ions in real samples

Schiff base compounds refer to the branch of supra-molecules and can be used as sensing material in the construction of potentiometric ion selective electrodes (ISEs). This relatively modern field has been subject to extensive research in the period of 1999-2007 when more than 100 ISEs employing Schiff bases were constructed. The quantitative high-throughput detection of 29 cations and 7 anions has been demonstrated in various scientific branches, such as biomedicine, pharmacy, biochemistry, pharmacology, environmental chemistry, food technology, and agriculture. This review discusses Schiff base compounds and their applications in the design and development of ion selective sensors and microsensors.     

Thiomorpholine-functionalized nanoporous mesopore as a sensing material for Cd2+ carbon paste electrode

A new thiomorpholine-functionalized nanoporous mesopore Mobil Composition of Matter No. 41 (MCM-41), abbreviated as TMMCM-41, was synthesized and applied as a sensing material in construction of a cadmium carbon paste electrode. The electrode composition of 20.1%wt TMMCM-41, 54.0% graphite powder, 25.9% paraffin oil showed the stable potential response to Cd²⁺ ions with the Nernstian slope of 28.6 mV decade^?1 (±1.8 mV decade^?1) over a wide linear concentration range of 10^?6 to 10^?2?mol L^?1 with a detection limit of 6?×?10^?7 mol L^?1. The electrode has fast response time and long-term stability (more than 4 months). The proposed electrode was used to determine the concentration of cadmium in tap water contaminated by this metal and cadmium electroplating waste water samples.     

Design of an Imipramine‐Selective Electrode Based on an Ion‐Pair and its Application to Pharmaceutical Analysis

Ion‐selective electrodes play an important role in pharmaceutical analysis due to their simplicity, rapidity and accuracy over some other analytical methods. This research introduces the design of an ion‐pair of imipramine‐tetraphenyl borate (IMP‐TPB) based PVC membrane sensor for IMP hydrochloride determination. Effect of the membrane composition, the pH influence and the effect of lipophilic anionic additives on the response characteristics of the electrode were investigated. After a series of experiments, the best electrode performance was accomplished with a membrane composition of 30% PVC, 63% DBP, 5% (IMP‐TPB) and 2% (NaTPB). This electrode illustrated a fast (15 s), stable and Nernstian response across a relatively wide IMP hydrochloride concentration range (10^?5 to 10^?5 M), in the pH range of (3.0–8.0), and it can be used for at least two months without any measurable change in sensitivity. Additionally, the interference between IMP and several drugs and common inorganic anions was negligible as shown by the potentiometric selectivity coefficient data. The membrane sensor was successfully applied to the determination of IMP in tablets and human urine samples, and very good recovery results were obtained.     

Zinc-Promoted Reduction of 1,2-Diketones: A Simple, Efficient, and Mild Approach to a-Hydroxy Ketones

Summary.  1,2-Diketones were readily converted to α-hydroxy ketones in high to excellent yields using zinc in saturated ammonium chloride solution. Received June 7, 2001. Accepted (revised) August 7, 2001     

One decade of research on ion-selective electrodes in Iran (1996–2006)

This review presents a general overview about the development of ion-selective electrodes in Iran during the past decade (1996–2006). All of the reported ion-selective sensors (for cations, anions and organic species) are cited in this review. Sensors for 39 cations, 12 anions, and 23 organic compounds and drugs have been reported in this reivew. Some of the main group cations (e.g. beryllium) as well as most of the lanthanide ion (i.e., presidium, erbium, lutetium, cerium, neodymium, europium, gadolinium, terbium, dysprosium, holmium, ytterbium, and thulium) sensors have been reported for the first time. It is noticable that the best reported sensors for HPO₄ ^2?, SO₄ ^2?, Cl^?, ClO₄ ^?, Br^?, and I₃ ^? have been designed and constructed by the Iranian researchers.     

WET ALUMINA-SUPPORTED CHROMIUM (VI) OXIDE: A MILD,EFFICIENT, AND INEXPENSIVE REAGENT FOR OXIDATIVE DEOXIMATION

A mild, efficient, [7.6pc] and inexpensive method for the direct conversion of oximes to carbonyl compounds upon treatment with wet alumina-supported chromium (VI) oxide is described.