Salman M. Saadeh

New room temperature ionic liquids with interesting ecotoxicological and antimicrobial properties.

A new set of room temperature ionic liquids (RTIL), tetrabutylammonium (TBA) salts: formate, acetate, propionate, butyrate, benzoate, nitrobenzoate, cinnamate, salicylate, sulfanilate, linoleate, and oleate, were prepared by neutralization of tetrabutylammonium hydroxide (TBA OH) and the corresponding acid. The compounds showed interesting chemical and biological properties. They are soluble in water and organic solvents producing conducting solutions and are effective against certain Gram-negative as well as Gram-positive bacteria. Notably, they affected some proteins such as bovine serum albumin (BSA) and catalase (CAT) as inferred by following the fluorescence emission spectra.

Enhanced sensitivity for Cu(II) by a salicylidine-functionalized polysiloxane carbon paste electrode

A new approach for decreasing the detection limit for a copper(II) ion-selective electrode (ISE) is presented. The ISE is designed using salicylidine-functionalized polysiloxane in carbon paste. This work describes the attempts to develop the electrode and measurements of its characteristics. The new type of renewable three-dimensional chemically modified electrode could be used in a pH range of 2.3-5.4, and its detection limit is 2.7 x 10(-8)mol L(-1) (1.2 microg L(-1)). This sensor exhibits a good Nernstian slope of 29.4+/-0.5 mV/decade in a wide linear concentration range of 2.3 x 10(-7) to 1.0 x 10(-3)mol L(-1) of Cu(II). It has a short response time (approximately 8s) and noticeably high selectivity over other Cu(II) selective electrodes. Finally, it was satisfactorily used as an indicator electrode in complexometric titration with EDTA and determination of copper(II) in miscellaneous samples such as urine and various water samples.

Development of novel potentiometric sensors for determination of tartrazine dye concentration in foodstuff products

Tartrazine dye Na(3)TZ in foodstuff products was determined by a new modified carbon paste electrode, encoded sensor A, and a coated silver wire electrode, encoded sensor B, based on tartrazine TZ- cetryltrimethyl ammoniumbromide CTAB as a chemical modifier TZ-CTA. The electrodes exhibit the following characteristics listed respectively: a Nernstian slope of 17.9±0.5 and 19.4±0.2 mV/decade for tartrazine ion over a wide concentration range from 4.3×10(-7) to 1.0×10(-2) and 1.1×10(-7) to 1.0×10(-2) M. The lower detection limits: 3.2×10(-7) and 5.5×10(-8) M. Short response time (5-8 s) over the pH range 3.8-7.7 and 4.2-8.1. The proposed sensors display significantly high selectivity for TZ ion over a wide variety of sugars, some anions, common organic, inorganic compounds and additives. The developed electrodes were applied to the potentiometric determination of tartrazine ion in different kinds of foodstuffs: solid jelly (strawberry and custard) powder samples and soft drink (orange) samples with satisfactory results.

A comparative study of chromium(III) ion-selective electrodes based on N,N-bis(salicylidene)-o-phenylenediaminatechromium(III)

A comparative study was made between three types of Cr(III) ion-selective electrodes: PVC membrane electrode, silver coated electrode and modified carbon paste electrode based on N,N-bis(salicylidene)-o-phenylenediaminatechromium(III) complex (Crsalophen). As anticipated, electrodes with a solid contact, rather than a traditional liquid inner contact, give lower detection limits because of diminished ion fluxes. Often, however, ill-defined solid contact gives rise to instabilities and interferences by oxygen gas. The carbon paste electrode provides a more sensitive and stable device than that afforded by PVC and coated electrodes. The best performance was obtained by an electrode based on the paste containing 3.5 wt% Cr-complex, 48.5% graphite plasticized with a mixture of 24.0 wt% tris(2-ethylhexyl) phosphate (DOPh) + 24.0 wt% dioctyl sebacate (DOS). The sensor has a linear dynamic range of 7.5 × 10-6 to 1.0 × 10-2 M, with a Nernstian slope of 20.1 ± 0.6 mV decade-1, and a detection limit of 1.8 × 10-6. It has a short response time of a bout 8 s and is applicable in a pH range of 4.5-7.7. It was successfully used as an indicator electrode in potentiometric titration of Cr(III) with EDTA and in determination of Cr(III) in water samples and chromium in (Crsalophen).

A new potentiometric sensor for the determination of ketamine hydrochloride in ampoules and urine

Ketamine drug in urine and pharmaceutical preparations was determined by a new chemically modified carbon paste electrode (CMCPE) based on an ion-exchanger of ketamine hydrochloride with sodium tetraphenylborate (KT-TPB) as a chemical modifier. The best performance was exhibited by the electrode having a paste containing 0.5 wt% ion-exchanger (KT-TPB), 54.3 wt% graphite, 45.0 wt% tris(2-ethylhexyl) phosphate (TEPh) and 0.2 wt% sodium tetraphenylborate (Na-TPB). The prepared electrode showed a Nernstian slope of 58.9 ± 0.3 mV per decade for ketamine ions in the concentration range of 9.0 × 10−6 M to 1.0 × 10−2 M with a limit of detection of 7.3 × 10−6 M. The electrode has a short and stable response time of 8 s and good reproducibility, and it can be used in a pH range of 3.7–6.6. The selective coefficients were determined in relation to several inorganic and organic ions, sugars and some common drug excipients. Ketamine is determined successfully in ampoule and urine using the standard addition and the calibration curve methods.

Synthesis and characterization of new NNO ligands and some metal(II) complexes: crystal structures of (BBH)2Co and (BIH)2Ni

The ligands 2-acetylbenzimidazole benzoylhydrazone (HBBH) and 2-acetylbenzimidazole isonicotinoylhydrazone (HBIH) were prepared and characterized by elemental analysis, IR, NMR, and mass spectra. The complexes of these ligands with Co(II), Ni(II), Cu(II), and Zn(II) were prepared by the reaction of methanolic acetate salts with the ligands in methanol in a 1 : 2 metal : ligand mole ratio. M(II)L2 were characterized based on elemental analysis, IR, NMR, MS, conductance, and electronic spectral measurements. Co(BBH)2 and Ni(BIH)2 were crystallographically characterized. They consist of two ligands that give six coordinate bonding to Co(II) and Ni(II) on a meridional plane through benzimidazole ring nitrogen, azomethine nitrogen, and benzoyl or isonicotinoyl oxygen, respectively. Co(BBH)2 crystallizes in the triclinic space group P and Z = 2 at 150 K with a = 9.9010(3) Å, b = 9.9705(4) Å, c = 15.8141(6) Å, α = 96.424(2)°, β = 94.1580(10)°, and γ = 92.153(2)°. Ni(BBH)2 crystallizes in the monoclinic space group P21/n and Z = 4 at 100 K with a = 14.3156(2) Å, b = 24.7402(4) Å, c = 19.8215(3) Å, α = 90°, β = 98.7761(7)°, and γ = 90°. The metal centers in these complexes have two ligands in a meridional, slightly distorted octahedron.

A new approach for decreasing the detection limit for a ketamine(I) ion-selective electrode

Our endeavors of lowering the detection limit for a ketamine(I) ion-selective electrode were described. The paper stresses the electrode which showed best results for determination of ketamine ion. The present electrode incorporates ketamine-phosphomolybdate (KT-PM) as ion-exchanger combined with the lipophilic anionic additive (Na-TPB) dissolved in dibutyl phthalate (DBP) as a plasticizer. The characteristics of the electrode were elaborately measured and its performance was tested in various samples and urine. It has favorable features as it provides measurements of the potential with a near-Nernstian slope of 56.6±0.3mV/decade over the concentration range of 1.5×10(-6)-1.0×10(-2)M over the pH range 3.0-6.8 in a short response time (7s). Importantly, it has a low detection limit of 1.2×10(-7)M and its life-span is 22days. Moreover, it displayed notable selectivity for ketamine ion over other species such as inorganic and organic cations and different excipients which may be present in pharmaceutical preparations. The sensor was applied for determination of KT ions in urine and pharmaceutical preparations using potentiometric determination, standard addition and the calibration curve methods. The standard deviation computed on the results indicated excellent repeatability of the measurements. Overall, it showed satisfactory results with excellent percentage recovery comparable to and sometimes better than those obtained by other routine methods for the assay.

Coated-Wire and Coated-Disc Cu(II) Ion-Selective Electrodes Based on Cu(II) Complex with Cyclized Salophen

Abstract Coated-wire and coated-disc ion selective electrodes (ISE) based on cyclized N,N ′-bis(salicylidene)-o-phenylenediamine (salophen) complex with Cu(II) were fabricated for determination of Cu(II) in aqueous solutions. The response of the ISE was optimized by variation of membrane composition and evaluation of the various experimental conditions. Near Nernstian slopes (˜28 mV/decade) were obtained. The linear range of the ISE ranged from 5 × 10−5 to 1 × 10−2 M Cu(II).The potentiometric selectivity coefficients (K ij ) were determined for , Ca2+, Mg2+, Ni2+, Pb2+, Zn2+, Cd2+, Co2+, Fe3+, Hg2+, , CH3COO−, Br−, I−, , and SCN−. The selectivity coefficients were in the range from 10−2 to 10−3 for all ions tested except Hg2+, I−, and to less extent Fe3+. The fabricated ISE using the Cu(II)-salophen complex are reliable and stable.