A sample-pretreatment method using a chitosan-based chelating resin, ethylenediamine-N,N,N'-triacetate-type chitosan (EDTriA-type chitosan), was developed for the preconcentration of trace metals in seawater and separation of the seawater matrix prior to their determination by inductively coupled plasma-mass spectrometry (ICP-MS). The resin showed very good adsorption for transition metals and ...

Peroxide bleaching is significantly affected by transition and alkaline earth metals. Isolating the effects of different transition and alkaline earth metals on the reactions of peroxide with different representative lignin structures allows the separation of the positive from the negative contributions of these metal ions. In this work, five monomeric or dimeric phenolic lignin model compounds...

alkali and alkaline earth metals hydrogen sulfate catalyzed the one-pot three component condensation reactions of aldehydes, 1,3-dicarbonyl compounds and urea or thiourea under solvent-free conditions leading to 3,4-dihydropyrimidin-2(1h)-ones in high yields at 80 °c. our results showed that biginelli reaction not only is ph dependent, but the cation of catalyst plays an important role.

INTRODUCTION In 1975, Small and coworkers first introduced the concept of ion chromatography (IC) that allowed the sensitive detection of ions using suppressed conductivity detection. A significant portion of this work was dedicated to cation analysis. The original components described by Small et al. for the separation of cations included a low-capacity, sulfonated polystyrene/ divinylbenzene ...

The ability of dead cells of endophytic Drechslera hawaiiensis of Morus alba L. grown in heavy metals habitats for bioremoval of cadmium (Cd2+), copper (Cu2+), and lead (Pb2+) in aqueous solution was evaluated under different conditions. Whereas the highest extent of Cd2+ and Cu2+ removal and uptake occurred at pH 8 as well as Pb2+ occurred at neutral pH (6-7) after equilibrium time 10 min. Ini...

A database of 1470 collision cross sections (666 doubly- and 804 triply-charged) of alkaline-earth-coordinated tryptic peptide ions [where the cation (M(2+)) correspond to Mg(2+), Ca(2+), or Ba(2+)] is presented. The utility of such an extensive set of measurements is illustrated by extraction of general properties of M(2+)-coordinated peptide structures. Specifically, we derive sets of intrins...

We present the use of hydrazone dynamic combinatorial libraries (DCLs) to identify macrocyclic receptors that are selective for alkaline earth metal ions over alkali metal ions. In particular, the toxic heavy metal ions Sr(2+) and Ba(2+) induce characteristic changes in the DCLs. Four macrocycles were isolated and characterised by LCMS, HRMS, NMR and X-ray crystallography; binding studies by UV...