[Advances in the fiber coating of solid phase micro-extraction]

Solid phase micro-extraction (SPME) is a simple and effective sample preparation technique and fiber coatings play a very important role in SPME process. The discussion begins with a brief historical perspective from the very early work conducted almost a decade ago. At the moment, more than 20 alternatives of fiber coatings and size are available. In this paper, the coatings are divided into two categories: commercial fibers and custom-made fibers. A novel so-gel method has been introduced for the preparation of the coatings.

[Synthesis and application of sulfonated beta-cyclodextrins as chiral additives in capillary electrophoresis]

Three new kinds of the sodium salt of sulfonated beta-cyclodextrins with different degrees of substitution were synthesized and characterized. A simple synthesis method was employed by direct sulfonating reaction with concentrated sulfuric acid. Sulfonated beta-cyclodextrins were used as chiral resolving agents for the capillary electrophoretic separation of enantiomers in high pH and low pH background electrolytes. In different electrophoretic polarity mode, the effects of the type and concentration of sulfonated beta-cyclodextrin were investigated. Sulfonated beta-cyclodextrins were proved to be strong complexing agents for basic and neutral analytes.

[Sample preconcentration technique in capillary electrophoresis]

The methods of improving the detection sensitivity in analysis of trace level components by sample preconcentration technique including sample stacking, field-amplified sample injection, isotachophoresis etc. are reviewed, and 67 references are cited.

[Enantiomeric separation of N-FMOC amino acids with sulfobutyl ether-beta-cyclodextrin as chiral additive by capillary electrokinetic chromatography]

Enantiomeric separation of N-FMOC amino acids by capillary electrophoresis with an anionic chiral resolving agent, sulfobutyl ether-beta-cyclodextrin (SBE-beta-CD) with average substitution degree of 3.8, employed as chiral additive was studied. Chiral separation was achieved with the mode of electrokinetic chromatography due to the electrophoretic mobility and chiral complexing ability of the chiral additive. The effects of pH of background electrolyte, the concentration of sulfobutyl ether-beta-cyclodextrin on enantiomeric separations were investigated. The enantiomeric separations of 8 N-FMOC amino acids were accomplished, among which 5 N-FMOC amino acids could be on baseline separated.

[Separation and determination of nycodenz and its impurities by capillary electrophoresis]

Separation and determination of nycodenz (a new radiography reagent) and its impurities by capillary electrophoresis was investigated. Since the analytes were polyols, Na2B4O7-H3BO3 was chosen as the buffer system. The analytes were negatively charged by complexing with borate. Then cetyltrimethylammonium bromide was used to reverse electroosmotic mobility in order to shorten the analysis time. 2-Propanol was added to optimize the separation further. Acceptable results of linearity, precision of corrected peak area and migration time were obtained. The RSD(n = 6) of corrected peak area and migration time were 0.73% and 1.4% respectively. The results obtained by CE were directly compared to those obtained by high performance liquid chromatography.

[Chemical constituents of Artemisia dalailamae Kraschen]

Five compounds were isolated from Artemisia dalailamae. They were identified as taraxeryl acetate, isofraxidin, scopoletin, scopolin and kumatakenin.