Separation selectivity of anionic metal complexes of N,N'-bis(hydroxybenzyl)ethylenediamine-N,N'-diacetic acid in ion and ion electrokinetic chromatography

Synthesis of a polyaminocarboxylate-based aluminum complex and its structural studies using 1H{13C}-HMBC NMR and a Karplus-type function

The HBED chelator is used to stabilize small and hard metal ions such as Fe³⁺, Ti⁴⁺, Ga³⁺ and Al³⁺ in both medicine and industry. While the coordination of hexadentate HBED^4- is known in the case of Fe³⁺, Ti⁴⁺ and Ga³⁺, it is unknown in the case of the small Al³⁺ ion since its corresponding complex has never been fully characterized. Thus, in this work the coordination pattern in a newly synthesized aluminum HBED-based complex ([Al-HBED-NN]^-Na⁺) was determined using 2D NMR in conjunction with DFT calculations.

Spectrophotometric Determination of Trace Amount of Copper(II) Ion Based on Complexation with an Anthraquinone Derivative

The spectrophotometric determination of Cu(II) with an anthraquinone derivative (Alizarin Red S) has been investigated. The experimental conditions, such as the pH of the sample and concentration of ligand, were optimized. This method is simple and sensitive for determination of Cu(II) ion. The interfering effects of diverse ions were investigated. Copper ion was determined by measuring the absorbance of the Cu(II)-ARS complex at 510 nm. Beer's law was obeyed over the concentration range of 0.011 - 0.320 mmol dm(-3) and the detection limit (S/N = 3) was 0.038 microg cm(-3). The relative standard deviation at 20 microg cm(-3) was 1.02% (n = 5). The method was applied for real samples.

Derivatization of inorganic ions in capillary electrophoresis

This review gives a short overview of the main approaches to the derivatization of inorganic ions in capillary electrophoresis (CE) with emphasis on the most recent works. Various derivatization procedures and detection methods are discussed. A brief account of their advantages and limitations is given. More specific areas such as microchip CE, simultaneous separation of anions and cations, and speciation analysis are also briefly discussed.

Modelling and optimization of the electrokinetic chromatographic separation of mixtures of organic anions and cations using poly(diallydimethyl- ammonium chloride) and hexanesulfonate as mixed pseudostationary phases

The separation of a series of aromatic carboxylic acids, sulfonates and opiates using electrokinetic chromatography employing a mixture of the soluble cationic polymer poly(diallydimethylammonium chloride) (PDDAC) and the amphiphilic anion hexanesulfonate as pseudostationary phases is described. In this system, the PDDAC pseudostationary phase interacts with the anionic analytes, whereas the hexanesulfonate pseudostationary phase interacts with the cationic analytes. A migration model has been derived which takes into account the ion-exchange (IE) interactions between the anions and the cationic PDDAC as well as the ion-pair (IP) interactions between the opiates and the hexanesulfonate. A further interaction between the combined PDDAC-hexanesulfonate complex and the more hydrophobic analytes is also evident and is accounted for in the model. Constants obtained by applying the model agreed well with the expected trends in IE affinities of the anions for PDDAC and also corresponded with the hydrophobic natures of the analytes. Optimization of the PDDAC and hexanesulfonate concentrations was performed using the normalized resolution product and minimum resolution product criteria. The minimum resolution product criterion proved to be most successful. An advantage of the described system is the improvement in peak shapes obtained after addition of hexanesulfonate to the electrolyte, resulting in increased plate numbers and better resolution. The system was very robust with mobilities varying by less than 2% over a period of days and on using different capillaries.

Use of ionic polymers as stationary and pseudo-stationary phases in the separation of ions by capillary electrophoresis and capillary electrochromatography

One of the problems with capillary electrophoresis is a lack of versatility regarding manipulation of the separation selectivity. A new and potentially universal concept is to introduce an ion-exchange component into a separation so that the migration of analyte ions is influenced by both their electrophoretic mobilities and their chromatographic properties. This may be accomplished by use of capillaries filled with or coated with solid ion-exchange polymers, or by addition of a soluble ionic polymer to the background electrolyte to create a pseudo-stationary phase. While each of these methods achieves the same result, they are not competitive, but rather complementary as the problems associated by one approach are overcome by the others. Recent highlights in the field are used to illustrate the flexibility that this approach provides to electrophoretic separation of ions.

Recent advances in capillary electrophoresis and capillary electrochromatography of pollutants

An overview of major developments in capillary electrophoresis and capillary electrochromatography systems in the environmental field is presented, covering relevant publications between the second half of 1999 and early 2001. Contributions are reviewed in relation to developments in detection, sample preparation/preconcentration, precision and applications. Many interesting examples are shown and the influence of important parameters on the performance of developed methods is discussed.