Polymeric Functionalized Stationary Phase for Separation of Ionic Compounds by IC

Synthesis and properties are described of multilayered stationary phases containing quaternary amine functional groups used for the analysis of inorganic anions by ion chromatography. The bonded phases were characterized by elemental analysis, solid state 13C NMR spectroscopy and chromatographic methods. The surface of polyhydroxyethyl methacrylate (solid support) was coated with polymeric layers formed by condensation polymerization of primary amine with diepoxide. Each layer of the anion exchange stationary phase consisted of methylamine and 1,4-butanedioldiglycidyl ether copolymer. A series of stationary phases with different number of polymerized layers were tested. Separation of inorganic anions, such as F−, Cl−, NO2−, Br−, NO3−, were performed. Aqueous hydroxide, carbonate and bicarbonate solutions were used as mobile phases

Distribution and statistical correlations for major, minor and trace metals in lake environments of Antarctica

This paper reports the distribution of minor and trace metals determined in water, algae, soil and sediment collected in different lakes in Antarctica, during the Italian Expedition in the austral summer 1993/94. The determination of the total concentration of the following metals was performed: Al, Ba, Ca, Cd, Co, Cr, Cu, Fe, K, Mg, Mn, Na, Ni, Pb, Sr, Zn. These have been determined in Carezza Lake (two temporally separate samplings) in Tarn Flat Lake and in Inexpressible Island Lake. The analytical results have been discussed with reference to their different meaning for matrices such as soil and sediment. Bivariate plots obtained with the factorial analysis for principal components have been obtained and discussed for lake water samples collected in the 1993/94 campaign and the previous ones (1989-1993). In addition a t-test correlation method showed that soil samples collected around the lakes and sediments sampled at the bottom of the lakes have equal composition with a coefficient correlation of 0.988 (95% confidence level)

Ion chromatographic separation of alkylsulphonic acids with conductivity detection

An ion chromatographic (IC) method has been developed for the separation of alkylsulphonic acid. Two different stationary phases, silica-based and polymer-based ion-exchange resins, were studied using pure ion exchange and/or hydrophobic interaction mechanisms. Correlations between analyte hydrophobicity and eluent polarity were made in order to investigate the possibility of changing the dominant separation mechanism by varying the eluent composition. The alkyl chain lengths of the sulphonic acids analysed ranged from C-1 to C-9. Detection limits in the submicromolar range were obtained by suppressed conductivity detection

Theory of bulk and flow electrolysis and approach to parameter optimisation for chromatographic electrochemical detection

The performance and characteristics of an amperometric-coulometric detector for liquid chromatography were investigated as a function of the main chromatographic parameters. Hydroquinone was chosen as reference compound. Starting from the theory of bulk and flow electrolysis, the effect of eluent flow rate on the detector response was investigated and the agreement between experimental and calculated data was verified. The study was preceded by an investigation of the detector behaviour in different chromatographic operating conditions: void volume evaluation, effect of mobile phase composition on baseline behaviour, current/potential curve for analyte and mobile phase, analyte stability, linearity, repeatability of the detector response and electrochemical exclusion from interferences were examined

The retention of metal species by different solid sorbents. Mechanisms for heavy metal speciation by sequential three column uptake

An apparatus consisting of three columns packed with different substrates, namely an anion exchange resin, a reversed phase sorbent and a chelating ion exchange resin, was developed. The retention of cadmium, copper and lead onto the substrates at different pH conditions was investigated, first by considering each column separately, then by connecting them in series. The aim of the study is to distinguish among species with different charge or chemical behaviour. Experiments were performed with the free metal ions, their anionic complexes with EDTA and 8-hydroxyquinoline-5-sulphonic acid, and their neutral complexes with 8-hydroxyquinoline. The results obtained were compared with those computed according to the theoretical species distribution of all species as a function of pH. The applicability of the technique to seawater was demonstrated