Ring statistics of silica bilayers.

The recent synthesis and characterisation of bilayers of vitreous silica has produced valuable new information on ring sizes and distributions. In this paper, we compare the ring statistics of experimental samples with computer generated samples. The average ring size is fixed at six by topology, but the width, skewness and other moments of the distribution of ring edges are characteristics of particular samples.

BZT: A Soft Pseudospin Glass.

In an attempt to understand the origin of relaxor ferroelectricity, it is shown that interesting behavior of the onset of nonergodicity and of precursor nanodomains, found in first-principles simulations of the relaxor alloy Ba(Zr(1-x)Ti(x))O(3), can easily be understood within a simple mapping to a soft pseudospin glass.

Hypercrosslinked strong anion-exchange resin for extraction of acidic pharmaceuticals from environmental water.

Two novel high-specific surface area polymeric sorbents (HXLPP-SAXa and HXLPP-SAXb) were synthesised and evaluated as solid-phase extraction sorbents. The novel sorbents under study are based on hypercrosslinked polymer microspheres and designed specifically to offer ion-exchange properties; the specific polymers of interest in the current work have been chemically modified in such a way as to impart a tuneable level of strong anion-exchange character onto the sorbents. The novel sorbents were applied as strong anion-exchange sorbents in solid-phase extraction studies, with the goal being to selectively extract a group of acidic compounds from complex environmental samples in an efficient manner.

Affinity chromatography in dynamic combinatorial libraries: one-pot amplification and isolation of a strongly binding receptor.

We report the one-pot amplification and isolation of a nanomolar receptor in a multibuilding block aqueous dynamic combinatorial library using a polymer-bound template. By appropriate choice of a poly(N,N-dimethylacrylamide)-based support, nonselective ion-exchange type behaviour between the oppositely charged cationic guest and polyanionic hosts was overcome, such that the selective molecular recognition arising in aqueous solution reactions is manifest also in the analogous templated solid phase DCL syntheses. The ability of a polymer bound template to identify and isolate a synthetic receptor via dynamic combinatorial chemistry was not compromised by the large size of the library, consisting of well over 140 theoretical members, demonstrating the practical advantages of a polymer-supported DCL methodology.

Weak anion-exchange hypercrosslinked sorbent in on-line solid-phase extraction-liquid chromatography coupling to achieve automated determination with an effective clean-up.

A mixed-mode polymeric sorbent was on-line coupled to liquid chromatography (LC) for the first time and applied to the selective solid-phase extract a group of pharmaceuticals in complex environmental water samples. The mixed-mode polymeric sorbent is a high-specific surface area hypercrosslinked polymer resin (HXLPP) in the form of monodisperse microspheres further modified with 1,2-ethylenediamine (EDA) moieties. These properties allow its application as a weak anion-exchange (WAX) sorbent in the on-line solid-phase extraction (SPE) coupling.