Hazem M. Abu Shawish

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.

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 solid and liquid inner contact benzalkonium chloride ion-selective electrode membranes

A comparative study was made between two designs of benzalkonium ion (Bz)-selective electrodes: a silver-coated (solid contact) called electrode A and a PVC membrane (liquid inner contact) called electrode B based on benzalkonium-phosphomolybdate (Bz-PM) as ion-exchanger complex. Electrode A has a linear dynamic range from 2.0×10(-8) to 1.0×10(-2) mol L(-1), with a Nernstian slope of 60±0.3 mV/decade and a detection limit of 2.0×10(-8) mol L(-1). Electrode B shows linearity over the concentration range from 2.0×10(-7) to 1.0×10(-2) mol L(-1), with a Nernstian slope of 55±1.2 mV/decade and a limit of detection of 1.5×10(-7) mol L(-1). Electrode A showed better performance than electrode B. The detection limit of benzalkonium chloride (BzCl) was effectively improved by a solid contact ion-selective electrode (SC-ISE), rather than the traditional liquid inner contact electrode that gives lower detection limits because of diminished ion fluxes. The present electrodes show clear discrimination of BzCl from several inorganic, organic ions, sugars and some common drug excipients. The sensors were applied efficiently for determination of BzCl in its pharmaceutical preparations (eye, ear and nasal drops) using standard addition and the calibration curve methods.

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.

Potentiometric Sensor for Determination of Tramadol Hydrochloride in Pharmaceutical Preparations and Biological Fluids

A potentiometric tramadol-selective electrode based on the ion-association of tramadol hydrochloride (TDCl) with phosphomolybdic acid (TD-PM) is developed. The electrode exhibits a Nernstian slope of 58.3±0.7 mV/decade for tramadol ions in the concentration range 2.0 × 10 -6 - 1.0 × 10 -1 M with the limit of detection of 1.3 × 10 -6 M. The electrode has a fast and stable response time 5-8 s, good reproducibility and it can be used in pH range of 1.8-6.1. The present electrode show good discrimination of tramadol hydrochloride from several inorganic, organic ions, sugars and some common drug excipients. These characteristics of the electrode enable it to be used successfully for determination of tramadol hydrochloride in its pharmaceutical preparations and biological fl uids (urine and milk).

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.

Nanomolar Detection of Alkyl Dimethyl Hydroxyethyl Ammonium Surfactant by a Lipophile-doped Solid Contact Electrode

Various methods for improving the lower detection limit of polymeric membrane ion-selective electrodes have been approached recently. The ion-selective electrode with solid-state membrane is described. Tetraphenyl borate as a lipophilic anion, is incorporated into the membrane of the electrode to improve its detection limit and selectivity. The detection limit was significantly lowered where nanomolar quantities were traced. Other favorable characteristics of the electrode are noticeably short response time of 5 seconds and good selectivity over the common interfering chemical species as well as its proven usefulness for determination of the surfactant in miscellaneous samples.