An iodine-123 generator/iodination kit: A preliminary report

Preliminary results are described of a¹²³Xe filled device to serve as a combination¹²³I generator/iodination kit.¹²³X was produced in the Brookhaven Linac Isotope Producer (BLIP) by the reaction¹²⁷I(p, 5n)¹²³Xe. The device consists of a small glass ampoule containing an internal glass breakseal and a flanged neck on which was crimped a multi-injection type septum. The ampoule contained a hydrogen sulfide atmosphere to assure that the iodine generated from the decay of the xenon was in the form of iodide. Following an adequate period for¹²³Xe to decay (this period can be used for shipment), a needle is forced through the septum breaking the seal and residual gases are pumped off. The¹²³I in the form of iodide can then be rinsed from the ampoule with any desired solvent or reagent added directly to the device to carry out an iodination in an enclosed environment. Preliminary results of both iodine recovery and iodinations have been promising. This research was supported by the US Department of Energy under Contract No. DE-ACO2-76CH0016.     

Use of p-Cresotic acid and its various derivatives for the estimation of thorium and zirconium

Summary p-Cresotic acid and its nitro, bromo, sulfo, acetyl, benzoyl and hydrazine derivatives and 5-methyl salicylic-o-aeetic acid have been used for the estimation of thorium and zirconium. The precipitates obtained have in all cases been ignited and weighed as oxides. These reagents have been found under suitable experimental conditions to effect the separation of Th as well as Zr from cerite earths.     

Copper(II) ion sensor based on electropolymerized undoped conducting polymers

A solid state copper(II) ion sensor is reported based on the application of electropolymerized undoped (neutral) polycarbazole (PCz) and polyindole (PIn) modified electrodes. The new sensor shows high selectivity to Cu²⁺ ions with a detection limit of 10^–5 M. PCz and PIn are formed respectively by the anodic oxidation of 50 mM carbazole and 5 mM indole monomers in dichloromethane containing 0.1 M tetrabutylammonium perchlorate on a platinum electrode using a single compartment cell. Potentiostatic polymerization of both the monomers are carried out at 1.3 V and 1.0 V vs. Ag/AgCl, respectively. Perchlorate ions were electrochemically removed from the polymer films by applying – 0.2 V vs. Ag/AgCl. Polymer-coated electrodes are incubated in 1 M KCl solution for 8 h followed by incubation in distilled water for 2 h before using as a metal ion sensor. The undoped PCz and PIn electrodes were found to be highly selective and sensitive for Cu²⁺ ions with little selectivity for Pb²⁺ and negligible response towards Ag⁺, Hg²⁺, Cu⁺, Ni²⁺, Co²⁺, Fe²⁺, Fe³⁺ or Zn²⁺. Potentiometric responses for Cu²⁺ ions are recorded for both the sensor electrodes together with a double-junction Ag/AgCl reference electrode. Calibration curves for Cu²⁺ are reported for both ion sensors. The polymer-modified electrodes were found to be stable for several weeks. Electronic Publication     

On the estimation of higher order resistance coefficients from electroosmotic transport data

Summary First and second order resistance coefficients between membrane matrix and permeant for the permeation of methanol, acetone and methyl ethyl ketone through pyrex and quartz membranes have been evaluated from the experimental data on electroosmotic effects. Analysis of the data shows that-the following non-linear relationP =R ₁₁ J _v +R ₁₂ I +R ₁₂₂ I ²[1] exists between pressure difference,P, and the fluxes and a linear relation =R ₂₁ J _v +R ₂₂ I [2] expresses the dependence of potential difference,, on the fluxes. The first order cross resistance coefficients have been found to obey theOnsager's reciprocity relation. An attempt has been made to explain the occurrence of higher order resistance coefficients in terms of electrokinetic character of the membrane, permeant interface.

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Zusammenfassung Die Widerstandskoeffizienten 1. und 2. Ordnung zwischen einer Membranmatrix und dem permeierenden Stoff wurden für die Permeation von Methanol, Aceton und Methyläthylketon durch Pyrex- und Quarz-Membranen auf Grund elektroosmotischer Effekte bestimmt. Die Auswertung gibt die nichtlineare BeziehungP =R ₁₁ J _v +R ₁₂ I +R ₁₂₂ I ² [1] zwischen der Druckdifferenz und dem Fließen; die lineare Beziehung =R ₂₁ J _v +R ₂₂ I [2] beschreibt die Abhängigkeit der Potentialdifferenz vom Fließen. Die gekreuzten Widerstandskoeffizienten 1. Ordnung gehorchen dem ReziprozitätsgesetzOnsager. Das Vorkommen von Widerstandskoeffizienten höherer Ordnung wird versuchsweise auf den elektrokinetischen Charakter der Membran-Grenzfläche zurückgeführt.

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With 2 figures and 2 tables     

Mass spectrometric determination of the heats of formation of the silane bromides

The reaction of SiBr₄(g) with H₂(g) in the temperature range 900–1143 K has been studied by a mass spectrometric method. Second and third law reaction enthalpies were obtained for SiBr₄(g) + H₂(g) = SiHBr₃(g) + HBr(g), SiHBr₃(g) + H₂(g) = SiH₂Br₂(g) + HBr(g), and SiH₂Br₂(g) + H₂(g) = SiH₃Br(g) + HBr(g). From the heats of reaction, third-law ΔH_£298 values of ?72.5 ± 1, ?43.2 ± 1.5 and ?15.3 ± 0.5 kcal/mole were obtained for SiHBr₃(g), SiH₂Br₂(g), and SiH₃Br(g), respectively.     

Spectrophotometric Determination of Palladium with Methylthymol Blue

A new, sensitive spectrophotometric method for the determination of palladium(II) with methylthymol blue has been developed. The palladium methylthymol blue complex has an absorption maximum at 530 nm. The colour reaction has a sensitivity of 0.005 µg of palladium/cm² and obeys Beer's Law over the range 0.4 to 3.24 ppm of palladium. The effects of concentration of perchloric acid, reagent, heating, stability of colour and diverse ions have been investigated. The ratio of metal: ligand in the complex is 1:1 and the formation constant was calculated to be 1.18×10⁴.     

Stability of AQUO-organic silver iodide sol

Summary The coagulation concentration for silver iodide sol, both in presence of pyridine and dioxane, increases for mono- and bivalent coagulating electrolyte. In presence of a mixture of pyridine and dioxane in equal volume, the coagulation concentration assumes an intermediate value, which is nearer to dioxane. However, in presence of dioxane more bivalent electrolyte is needed than in presence of pyridine. If a bivalent coagulating electrolyte is added to a sol containing a mixture of pyridine and dioxane, the amount of electrolyte required to coagulate is less than pyridine and greater than dioxane. Thus silver iodide sol is more stable toward mono- and bivalent coagulating electrolytes. The degree of stabilization increases with the decrease of the dielectric constant of the dispersing medium. The intermediate values for dioxane pyridine mixture is accountable by the fact that dioxane acts as a solvent for pyridine. The PH value of the sol increases up to the coagulation point. Beyond this, there is an abrupt decrease. When the particles settle down completely a rise in PH is again noted on the further addition of electrolytes. The increase in the electrical conductance is more significant after coagulation. These changes have been explained by adsorption of the ions and due to the release of ions from the electrical double layer.

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Zusammenfassung Die Koagulationskonzentration für Silberjodidsol in Gegenwart von Pyridin und Dioxan steigt für ein- und zweiwertige Elektrolyte an. In Gegenwart einer Mischung zu gleichen Volumen erh?lt man mittlere Werte, n?her denen zu Dioxan. Für Koagulation in Gegenwart von Dioxan ist jedoch mehr zweiwertiger Elektrolyt notwendig als in Gegenwart von Pyridin. Bei Koagulation mit zweiwertigem Elektrolyt verbraucht ein Sol mit der Mischung von Pyridin und Dioxan weniger als für Pyridin und mehr als für Dioxan. Daher ist das Silbersol gegenüber ein- und zweiwertigen Elektrolyten stabiler. Der Grad der Stabilisierung w?chst mit abnehmender Dielektrizit?tskonstante des Dispersionsmediums. Die Zwischenwerte der Dioxan-Pyridin-Mischungen lassen sich verstehen durch die Tatsache, da? Dioxan als L?sungsmittel für Pyridin wirkt. Der PH-Wert des Sols w?chst bis zum Koagulationspunkt, darüberhinaus erfolgt ein steiler Abfall. Wenn die Teilchen vollst?ndig absetzen, ist bei weiterer Zugabe von Elektrolyt ein erneuter Anstieg im PH feststellbar. Der Anstieg der elektrolytischen Leitf?higkeit wird nach der Koagulation ausgepr?gter. Diese ?nderungen lassen sich durch Ionenadsorption und Freiwerden von Ionen aus der elektrischen Doppelschicht erkl?ren.

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Our thanks are due to Prof. R. C. Mehrotra for providing all the facilities for this work and to Prof. S. Ghosh of Allahabad University for helpful discussions. Thanks are also due to the University Grants Commission, Government of India, for the award of a research scholarship to one of us (V. K. S.).     

Identification of novel alpha-glucosidase inhibitors by screening libraries based on N- [4-(benzyloxy) benzoyl] alanine derivatives

A library of 72 compounds related to N- [4-(benzyloxy) benzoyl]alanine (I) was synthesized, prepared and screened for alpha-glucosidase inhibitory activity. Four compounds showed potent inhibition, six compounds moderate inhibition, and 16 were weak inhibitors. One compound, N- [4-(benzyloxy) benzoyl] serine, was found to be a potent inhibitor of alpha-glucosidase with 100% inhibition at 1 micro M. This inhibitor was at least five times more potent than the lead compound I.