Cu(I) assisted radioiodination of hippuran with no carrier added131I

A study on the labeling of hippuran with no-carrier-added¹³¹I assisted by Cu(I) and excess of ascorbic acid is described. The role of ascorbic acid is to prevent the oxidation of Cu(I) to Cu(II) which activates the hydrolysis of o-iodohippuric acid to o-iodobenzoic acid. The use of Cu(I) allows an almost quantitative (97–99%) labeling yield to be obtained within 10–15 minutes at 100°C. The reaction is assumed to take place via the formation of an organocopper complex favoring the exchange reaction between radioiodine and inactive iodine in the hippuran molecule. The activation energy of the reaction was calculated to beE=12.2 kcal/mol.     

A coulometric method for the assay of some easily oxidized organic substances with iodine as an oxidizing agent

A coulometric method for the assay of easily oxidized organic substances, using iodine as an oxidizing agent, has been developed. The principle of the method is to oxidize the substance with an excess of iodine in a water-acetic acid medium and then titrate the iodide formed, with anodically generated silver ion. The titration is followed by dead-stop indication using two platinum electrodes. The method has been applied to the assay of dihydric phenols with hydroxyl groups in the ortho or para positions and to the determination of ascorbic acid in various pharmaceutical preparations. The absolute relative error varied between 0.2 and 2.8% for the 8 phenols investigated and the relative standard deviation between 0.2 and 1%. For standard solutions of ascorbic acid the absolute relative error was 0.9% and for the 6 pharmaceutical preparations investigated the relative standard deviation lay in the range 0.3-0.9%. The method is easy to apply and has a number of advantages over current iodimetric methods.     

Production of no carrier added residue free22Na

A method for the production of no carrier added and residue free²²Na, was developed via the²⁴Mg/d, /²²Na nuclear reaction applying 14 MeV deuterons and a high current Mg–Cu target. The yield for the reaction target. The yield for the reaction was measured and the chemical separation performed using a Dowex 50WX8 resin in H⁺ form. The overall yield was higher than 98%. Residue could not be detected. All experiments were carried out at IEN's CV-28 cyclotron.     

Iodine monochloride in anhydrous acetic acid as an oxidizing agent

A systematic study of the redox reactions of iodine monochloride with various inorganic ions in glacial acetic acid medium is described. Sodium sulphite, mercury(I) perchlorate, antimony trichloride, arsenic trichloride and iron(II) perchlorate were examined. Potentiometric and amperometric methods were used to follow the reduction of iodine monochloride, which yields different products according to the type of reductant.     

2-Iodylbenzoic acid as an oxidizing agent for the determination of certain thioxanthene derivatives

An indirect titrimetric method is described for the determination of chlorprothixene, methixene and thiothixene. A known and excessive volume of 2-iodylbenzoate is added and after a specified time the surplus is determined iodometrically. The method has been applied to the analysis of pharmaceutical preparations containing these drugs and the results obtained compare favourably with those from the pharmacopoeial methods. The method is simple, accurate and precise.     

A condition variation study for radioiodination via triazene intermediates

Pyrrolidyl triazenes prepared by interception of the diazonium transient in the Sandmeyer reaction of amines can serve as useful intermediates in the iodination and radioiodination of aryl rings. Decomposition of such triazenes in the presence of iodide is acid-catalyzed and is sensitive to choice of solvent, acid, and triazene structure. A condition variation study by HPLC of four different solvent systems and two non-nucleophilic acids was carried out on the¹²³I iodination of the triazenes of p-nitroaniline, p-anisidine and p-toluidine. This method has proven useful in radiolabeling of two pharmaceutical analogs which were not amenable to labeling through the classic Sandmeyer method.     

The production of no carrier added arsenic radioisotopes in nuclear reactors

The comparative advantages and drawbacks of some reactor-produced arsenic radioisotopes having favourable characteristics for their use as tracers are discussed. The study comprises their preparation based on: (a) capture reactions on germanium; (b) threshold reactions on germanium, selenium and bromine; (c) secondary reactions on germanium, induced by recoil protons and tritons produced by the action of neutrons on lithium. The recommended options for the production of relatively short half-life radionuclides are ⁷⁷As by capture on germanium or ⁷⁶As via (n,α) reaction on bromine, while two different ways are applicable for the production of ⁷⁴As, longer-lived radioisotope.

     

Phase state stabilization of ammonium nitrate for creating an oxidizing agent for smokeless gas-generating formulations yielding no toxic combustion products

Methods for phase stabilization of ammonium nitrate were sought for in order to considerably expand the application area of this oxidizing agent in various-purpose self-combustible formulations, including that in a new generation of gas-generating formulations for automobile air bags. New methods for stabilization of ammonium nitrate were studied and, in particular, a search was made for organic compounds that can stabilize ammonium nitrate even at their low content. The mechanism of phase state stabilization of ammonium nitrate by compounds of this kind was examined.     

Irradiation methods for production of high specific activity radionuclides in no carrier added form

High Specific Activity Radio-Nuclides (HSARN) are a powerful tool to label a large range of chemical species at very low concentration levels. In order to obtain these radiotracers in a very high specific activity form, it is necessary to optimize the production methods, to separate and purify them from the irradiated target without the addition of inactive carrier, to carry out a series of analytical and radioanalytical tests to determine their true specific activity and to verify a series of purity parameters. A review of irradiation methods and nuclear parameters adopted in our laboratories for the preparation of some tens of radiotracers are presented.     

Use of Dacron as an alternative carrier for evaluating oxidizing sterilants in the AOAC sporicidal test

The AOAC sporicidal method (966.04) recommends the use of porcelain penicylinders and black waxed silk sutures as carriers for demonstrating the sporicidal activity of sterilants. However, the silk carriers are not suitable for evaluating the sporicidal efficacy of oxidizing agents, and an inert polyester material (Dacron) is recommended as an alternative. Dacron provides an equivalent microbial and physical challenge to silk. Microbiologically, both materials demonstrated similar HCI resistance, which is required by the AOAC test, as well as equivalent spore loading and spore wash-off. Electron microscopy showed that both materials present the same braided microstructure, providing an equivalent physical challenge to the test sterilant. Dacron was more consistent than silk, and did not require extraction prior to spore loading. The extraction method for black waxed silk was variable and incomplete, which may compromise the activity of oxidizing sterilants and add to method variability. Silk was also structurally altered in the presence of oxidizing sterilants and increased sterilant degradation. Dacron did not affect the sterilant and was inert in the presence of oxidizing agents. Dacron sutures are proposed as inert alternatives to silk for evaluating the sporicidal efficacy of oxidizing agents.     

Trivalent molybdenum as volumetric reducing agent for admixed oxidizing agents

Summary The aim of this study was to test the applicability of trivalent molybdenum as a volumetric reducing agent for mixtures of two and three oxidizing agents. The oxidizing agents used were ceric, vanadate dichromate and ferric solutions. All possible combinations of two and three ions were attempted. With the exception of a few cases, successful results were obtained with mixtures of two ions. Accurate determinations with three ions admixed could not be achieved; however, a close estimation was possible in some cases.     

A rapid method for the estimation of glutamic acid with chloramine-T

Chloramine-T (added in excess) oxidizes glutamic acid in various solvent media and the reaction is rapid and stoichiometric with a 4-electron change in buffers of pH 1-6, in 0.01 M sulphuric and perchloric acids and in 0.1M hydrochloric acid. A back-titration procedure using a pH-4 buffer or 0.1M hydrochloric acid as reaction medium has been developed. rho-Toluenesulphonamide and a nitrile have been identified in the reaction products. The effect of other species on the oxidation has been investigated.     

Determination of pentoxifylline in pharmaceutical formulations using iodine as oxidizing agent

Simple, selective and sensitive spectrophotometric methods are described for the determination of pentoxifylline, based on the haloform reaction with a known and excess of standard iodine solution under alkaline conditions. The excess of iodine is determined at pH 3.0 with metol–isoniazid (λ_max=620 nm; method A) or wool fast blue BL (λ_max=540 nm, method B). All the variables have been optimised and the reaction mechanisms presented. Regression analysis of Beer's law plots showed good correlation in the concentration ranges 4.0–24.0 and 0.4–2.4 mg ml⁻¹ for methods A and B respectively. No interferences were observed from excipients and the validity of the methods was tested by analysing pharmaceutical formulations. Recoveries were 99.0–100.0%. The concentration measurements were reproducible within a relative standard deviation of 1.0%.     

钒酸铵氧化-分光光度法测定盐酸氯丙嗪

在磷酸介质中,钒酸铵与盐酸氯丙嗪反应生成红色氧化产物,其最大吸收波长为524nm;据此建立了测定盐酸氯丙嗪含量的钒酸铵氧化-分光光度法,并将其用于直接测定药物制剂中的盐酸氯丙嗪.结果表明,当盐酸氯丙嗪的浓度处于10.0～100mg/L和100～360mg/L范围内时,被测定体系的吸光度与盐酸氯丙嗪的浓度之间呈良好的线性关系;线性回归方程分别为A=-0.061 69+0.010 05c(mg/L,r=0.998 8)、A=0.494+0.004 43c(mg/L,r=0.998 8),检出限为1.96mg/L,相对标准偏差为0.29%,回收率为94.9%～102.9%.     

A high-yielding, one-pot preparation of unsymmetrical glycosyl disulfides using 1-chlorobenzotriazole as an in situ trapping/oxidizing agent

A high-yielding, one-pot methodology for preparing unsymmetrical glycosyl disulfides derived from sugar, alkyl/aryl or cysteine thiols is reported using 1-chlorobenzotriazole (BtCl) as the oxidant. The highlight of the method is the low temperature of coupling (−78 °C) as well as the in situ trapping of the sulfenyl intermediate, which ensures that no homodimer of R¹SH (R¹SSR¹) is formed. The coupling efficiency is independent of sugar type, thiol position in the sugar, sugar-protecting groups, and the various products serve to illustrate the rapid synthetic access to a number of model systems in glycobiology.     

Titrimetric microdetermination of chromotrope 2R: Ceric sulfate as oxidizing agent

Chromotrope 2R has been quantitatively determined in micro amounts by oxidizing with ceric sulfate in highly acidic medium. The reaction is completed at 40 equivalence; and the rupture of the molecule results in the formation of formic acid as the main oxidation product. Maximum error observed is 1.0%. The method is simple, accurate, and reproducible.     

Titrimetric microdetermination of solochrome black T: Ceric sulfate as oxidizing agent

Solochrome black T has been quantitatively determined in micro amounts by oxidizing with ceric sulfate in highly acidic medium. The reaction between solochrome black T and ceric sulfate is completed at 16 equivalence resulting in the formation of p-nitrophthalic acid and 1,2-dihydroxy naphthalene as main oxidation products. Maximum error in these experiments has been observed as 1.6%. The method is accurate, gives reproducible results, and is less time consuming.     

Epoxy resin modified with amine as an effective complexing agent of metal cations

A simple synthesis of a material capable of metal cation removal is proposed. The material was a derivative of epoxy resin containing amine groups. It is insoluble in water and in this study it was characterized by elemental analysis and infrared spectroscopy. The sorbent obtained was tested for its ability to remove coper(II), cadmium(II) and lead(II) from water solutions. The tests were performed for different concentrations of metal ions (10–200 mg L^?1) and at different pH (2.0–9.0). The effects of temperature and stirring time, as well as reusability of the sorbent were also studied in batch experiments. In the optimum conditions, the decrease in the cation concentration in aqueous solutions was observed in the order Cu>Pb>Cd but for each ion the decrease was at least 50% of the initial concentration. The sorbent has demonstrated high effectiveness in cation sorption and after regeneration it can be applied repeatedly in the process described.