Az ionkromatográfia retenciós elmélete és alkalmazásai a kémiai analízisben = Retention theory of ion chromatography and its applications in analytical chemistry

1. Ivóvizek mikrobiológiai kezelése során a klórozó szer és a gyakran jelenlevő bromid a szerves anyagokkal reakcióba lép és nagy variációjú klór és bróm-tartalmú toxikus haloecetsavak (HAAc) keletkeznek.Érzékeny és szelektiv ionkromatográfiás módszert fejlesztettünk ki polimer alapú makrociklikus állófázis (D222) és vezetőképességi detektálás alkalmazásával nyolc különböző HAAc szimultán meghatározására. 2. A fém-ligandum komplexek kialakítása és kölcsönhatásai szelektív HPLC elválasztásokra adnak lehetőséget. Fém-kelát komplexek ionkromatográfiás meghatározására nagyhatékonyságú módszert fejlesztettünk ki pellikuláris anioncserélő oszlopon. Ligandumok, mint szerves anionok, fémek, mint anionos komplexek szimultán elemezhetők. Ezek a vízoldható komponensek (Zn2+, Cu2+, Fe3+, Al3+, Mg2+, EDTA, DCTA) a talajt és a vizeket szennyezhetik, ezért az eljárás különösen fontos a komplex környezeti minták elemzésében. A komponensek retenciós sorrendjét a különböző fémek ligandumokkal alkotott stabilitási viszonyai és a bázikus eluens pH-ja által szabályozhatjuk. 3. Retenciós modellt vezettünk le egyensúlyi kémiai megfontolások és a sztochasztikus elmélet alapján anionok retenciós adatainak becslésére és a csúcsalakok előzetes leirására. Alkalmazásával fontos gyakorlati problémákat oldottunk meg (pl. nyommennyiségű ionok elúciója nagy koncentrációjú matrixban, egy- és többértékű ionok várható retenciós profiljának leírása). | 1.During the disinfection process in drinking water, chlorine and possible bromine, can also react with organic matter in raw water, producing a wide variety of toxic chlorine- and bromine-containing haloaceticacids.High performance ion chromatographic method was developed for the analytical separation of eight chloro- and bromo-haloacetic acids using macrocycle based anion-exchange column and conductivity detection. Selectivity of the system for components has been increased . 2.Metal-ligand complex formation have great potential for the development of selective separations in HPLC. Ion-chromatography of metal-multidentate agents were performed on pellicular anion-exchange column. In this method, ligands as anions and metals as anionic complexes can be separated in a single run. These species form water soluble complexes (Zn2+, Cu2+, Fe3+, Al3+, Mg2+,EDTA, DCTA), which may result in contamination of soils and waters. Retention of ligands, metal-complexes may be explained by the complex stability and with pH of eluent. 3. Retention model based on ionic equilibrium and stochastic theory has been developed in order to describe retention data of anions and provide peak shape simulation in chromatograms. By simultaneous application of two theories the full chromatograms of known sample mixtures were predicted.Theoretical models were applied to solve practical problems in separation of trace anions in presence of high matrix and to describe of retention profiles of anions

Adsorption of Cr(VI) and Speciation of Cr(VI) and Cr(III) in Aqueous Solutions Using Chemically Modified Chitosan

A new type of grafting chitosan (CTS) was synthesized using 2-hydroxyethyl- trimethyl ammonium chloride (HGCTS). The adsorption of Cr(VI) on HGCTS was studied. The effect factors on adsorption and the adsorption mechanism were considered. The results indicated that the HGCTS could concentrate and separate Cr(VI) at pH 4.0; the adsorption equilibrium time was 80 min; the maximum adsorption capacity was 205 mg/g. The adsorption isotherm and kinetics were investigated, equilibrium data agreed very well with the Langmuir model and the pseudo second-order model could describe the adsorption process better than the pseudo first-order model. A novel method for speciation of Cr(VI) and Cr(III) in environmental water samples has been developed using HGCTS as adsorbent and FAAS as determination means. The detection limit of this method was 20 ng/L, the relatively standard deviation was 1.2% and the recovery was 99%~105%

Prospectus, September 1, 1993

https://spark.parkland.edu/prospectus_1993/1012/thumbnail.jp

Determination of sub-ppb epichlorohydrin levels in water by on-line solid-phase extraction liquid chromatography/tandem mass spectrometry

A new sensitive and selective method based on on-line solid-phase extraction (SPE) coupled to liquid chromatography/electrospray ionization tandem mass spectrometry (LC/ESI-MS/MS) using a triple quadrupole mass spectrometer has been developed for the determination of epichlorohydrin (ECH) in different types of water samples. ECH is not easily determined directly by ESI-MS as it is not readily ionized, and it has a low molecular mass and high polarity. Thus, prior derivatization of ECH was necessary, employing 3,5-difluorobenzylamine as a derivatizing agent with Fe(III) as a catalyst. In order to achieve accurate quantification, correcting for matrix effects, losses in the derivatization process and instrumental deviations, isotope labelled ECH (ECH-d(5)) was added as an internal standard (IS) to the water samples. The method was validated based on European SANCO guidelines using drinking and other types of treated water spiked at two concentration levels (0.1 and 1.0 microg/L), the lower level having been established as the limit of quantification (LOQ) of the method. Satisfactory accuracy (recoveries between 70 and 103%), precision (RSD 0.99) were obtained. The limit of detection (LOD) was set up at 0.03 microg/L. The method was applied to different water samples (drinking water and water samples collected from a municipal treatment water plant). In order to enhance confidence, five selected reaction monitoring (SRM) transitions were acquired, thus obtaining a simultaneous reliable quantification and identification of ECH in water, even at sub-ppb level