Rapid determination of 90Sr in urine samples using AnaLig® Sr-01

This paper describes the use of IBC’s AnaLig^® Sr-01 molecular recognition technology product to effectively and selectively pre-concentrate, separate, and recover strontium from urine samples. This method uses two-stage columns separation consisting of two different commercial products Eichrom’s Pre-filter Material and AnaLig^® Sr-01 column from IBC Advanced Technologies. This method does not involve co-precipitation of strontium as phosphates and oxalates from urine samples. The new rapid method separates strontium-90 with high chemical recovery.     

A simple,efficient, regioselective and one-pot preparation of N-hydroxy- and N–O-protected hydroxyindoles via cycloaddition of nitrosoarenes with alkynes. Synthetic scope,applications and novel by-products

The thermal reaction between nitrosoarenes and alkynes under alkylating conditions produces N-alkoxyindoles as the major products in moderate to good yields and excellent regioselectivity. Various electrophiles are used affording different N–O-protected hydroxyindoles in a multi-component fashion. Privileged acetylenic substrates used in reactions with substituted nitrosoarenes are arylalkynes or propiolates. Potentially bioactive compounds and other classes of highly functionalizable indole products were prepared. Reactions between o-carbomethoxy-nitrosoarenes and arylacetylenes provided tricyclic compounds containing an acylaziridine indoline skeleton.     

Hydrogen bonding in macrocyclic receptor systems

Abstract

The interactions of macrocyclic polyethers with alkali and alkaline earth cations have been well studied and much about their chemistry is now well understood. Less well examined or comprehended are hydrogen bond interactions. A combination of ion selective electrode binding constant determination techniques and fast atom bombardment mass spectrometry are brought to bear on this problem. It is found that all-oxygen crown ethers and their derivatives exhibit quite different complexation behaviour with ammonium salts than do their various azacrown counterparts.     

How do we know who to include in collaborative research? Toward a method for the identification of experts

Collaborative research, defined as research involving actors participating in the problem situation under study, has an important role in operational research, strategic management and systems thinking. In a recent study, we found that a strong organizational focus incorporated into many soft operational research (OR) approaches is inadequate for studying societal problem situations, which are fragmented and have no clear boundary. Specifically, we failed to find a process of identifying individuals that is capable of representing the perspectives of actors and sufficient for research into societal problem situations. We found no clear terminology accounting for ontological differences between actors, individuals representing them and conceptual representations of acting entities. In response to this gap in the literature, we propose terminology that differentiates among actors (individuals or collective entities in the real world), experts (individuals capable of representing the perspective of an actor) and agents (ideal-typical representations of actors). Based on this terminology, we propose an iterative method to guide the assembly of an expert group to undertake collaborative research into societal problem situations. To demonstrate the application of our method, we present selected insights from our study in an electronic supplement.     

Determination Of Formaldehyde And Acetaldehyde Associated To Atmospheric Aerosols By HPLC

Abstract

A rapid new analytical protocol was developed for the determination of formaldehyde and acetaldehyde associated to atmospheric particulate matter, at ng/m³ levels. The aerosols were collected on glass fiber filters (8″×10″) at face velocities ranging from 15 m/min to 23 m/min. Aliquots of 15.4 cm² were sonicated, for 20 min, with 5.0 mL of 0,01% 2,4-dinitrophenylhydrazine (DNPH), 1 % phosphoric acid. The liquid phase was then filtered and the separation and quantification of the corresponding 2,4-dinitrophenylhidrazone (DNPHo) derivatives carried out by reverse phase HPLC. Acetonitrile:water (57:43, v/v) as mobile phase at 1.0 mL/min and absorbance detection at 350 nm and 365 nm for, respectively, formaldehyde-DNPHo (0.04 AUFS) and acetaldehyde-DNPHo (0.01 AUFS) were used. The precision for four different aliquots, from a 8″×10″ glass fiber filter, were under 0.04% for formaldehyde and 14.16 % for acetaldehyde. In Salvador, Bahia, Brazil, formaldehyde and acetaldehyde were determined, respectively, in the range of 6.8 ng/m³ to 27.3 ng/m³ and 9.1 ng/m³ to 54.6 ng/m³.     

Introduction of C-Sulfonate Groups into Disaccharide Derivatives

To prepare C-sulfonate derivatives of disaccharides two different strategies were followed. Thus 6- and 6′-C-sulfocellobiosides 4 and 10–12 were prepared starting from a suitably protected cellobioside. The 6′-C-sulfoaminocellobioside 18 was prepared by construction of the molecule through a glycosylation reaction. In both cases, the synthetic pathway involves regioselective tosylation, introduction of a sulfur atom by nucleophilic displacement with potassium thioacetate and oxidation with hydrogen peroxide.