Effect of temperature on the retention of amino acids and carbohydrates in high-performance anion-exchange chromatography.

Effect of temperature on the retention of amino acids and carbohydrates in high-performance anion-exchange chromatography (HPAEC) was investigated. Amino acids retention exhibited both exothermic and endothermic behavior. Significant selectivity variations of some weakly retained amino acids were achieved through changing temperature.

Multi-walled carbon nanotubes as a solid-phase extraction adsorbent for the determination of chlorophenols in environmental water samples.

Multi-walled carbon nanotubes (MWCNs) are used as adsorbent for solid-phase extraction (SPE) of several chlorophenols (CPs). CPs were adsorbed on MWCNs cartridge, then desorbed with pH 10.0 methanol, finally determined by HPLC.

[Investigation of bromate, haloacetic acids and perchlorate in Beijing's drinking water].

Disinfection by-products and perchlorate in the raw water and finished water of Beijing's a drinking water plants were investigated. The results indicated that there was little bromate in the drinking water. Five haloacetic acids (HAAs) were found in the water.

Some factors affecting separation and detection of amino acids by high-performance anion-exchange chromatography with integrated pulsed amperometric detection.

Some factors influencing the separation and detection of amino acids by high-performance anion-exchange chromatography with integrated pulsed amperometric detection were investigated. These factors include eluent concentration, column temperature, and detection waveform. The selectivity changes in weakly retained amino acids are slight with changing sodium hydroxide eluent concentration.

Investigation of interferences caused by extraneous chloride in the analysis of inorganic anions with ion chromatography.

A series of experiments were conducted by adding Cl- to the eluent to simulate the contaminated eluent. It was found that the added Cl- would cause the peak response of the anions increase largely. Because of the introduction of the superfluous H+, the total conductivity of each anion band was enhanced, and it was regarded as the increase of the sample anion.

[Preparation of monodispersed agglomerated pellicular cation exchange resins and its chromatographic properties].

A new and simple method for the preparation of latex-coated pellicular cation exchanger is introduced. Chromatographic stationary phase of monodispersed agglomerated pellicular cation was prepared for the first time. The monodispersed polyvinylbenzene-divinylbenzene (PSTDVB) particles (10 microns) as substrate beads were functionalized with a tertiary amine on the surface at first and then attached with a layer of sulfonated latex particles (0.

[Determination of trace level of bromate and perchlorate in drinking water by ion chromatography with microwave preconcentration].

A simple sample preconcentration technique for the determination of trace level of bromate and perchlorate in drinking water with ion chromatography is presented. With the hydrophobic anion-exchange column and a sodium hydroxide eluent in linear gradient, bromate and perchlorate can be determined in a single injection within 35 min. Prior to ion chromatographic analysis, the drinking water sample was treated with the OnGuard Ag cartridge to remove the superfluous chloride and concentrated in 20-fold with poly(tetrafluoroethylene)(PTFE) beaker in a domestic microwave oven in 15 min.