Biomedical subjects

S L Da

Publications and source records attributed to S L Da.

4 recordsLinked to original sources

PubMed2001

[Advances in solid phase microextraction coupled with high performance liquid chromatography].

Solid phase microextraction (SPME) is a solvent-free technique with high extraction efficiency and easy to perform automatically. It can be coupled with high performance liquid chromatography to perform efficient analysis of compounds with high polarity. The advances in solid phase microextraction coupled with high performance liquid chromatography, including its theory, interfaces, coating materials and applications, are reviewed with 36 references.

Chromatography, Gas↗

PubMed2000

[Retention behavior of some polycyclic aromatic hydrocarbons on alkylphosphonate-modified magnesia-zirconia composite stationary phase for reversed-phase liquid chromatography].

An alkylphosphonate-modified magnesia-zirconia composite stationary phase (PZMS) for reversed-phase liquid chromatography was prepared. The reversed-phase chromatographic performance of the new packing material was investigated with some polycyclic aromatic hydrocarbons (PAHs) as solutes. The effect of the methanol content in the mobile phase on the retention of PAHs was examined. The logarithmic capacity factor of PAHs was decreased linearly with increasing volume percent of the methanol in the mobile phase, which is similar to that observed on Zorbax ODS. The capacity factor of PAHs on the new stationary phase was also correlated to their partition coefficient between n-octanol and water (log P). A good linear relationship between them was obtained. These results show that the new material can behave as a reversed-phase packing. The separations of phenanthrene and anthracene, and terphenyl isomers were investigated on the new stationary phase and the Zorbax ODS, respectively. The retention of the solutes on the Zorbax ODS is greater than that on the new stationary phase, but the separation selectivity of the solutes on the new stationary phase is better than that on the Zorbax ODS. The better separation selectivity on the new stationary phase may be contributed from the Lewis acid-base interaction between the solutes and the residual Lewis acid sites on the stationary phase.

Alkylation↗

PubMed2000

[Preparation and evaluation of glycine derivatized beta-cyclodextrin bonded silica for high performance liquid chromatography].

Glycine derivatized beta-cyclodextrin bonded silica (GCDS) has been prepared for high performance liquid chromatography through the reactions of beta-cyclodextrin bonded silica with tosyl chloride and glycine in sequence. The separation performance of GCDS for positional isomers, dansyl amino acids and phenylpropionic acids was investigated. It was found that nitrophenols could not be eluted with methanol as mobile phase, but could be eluted with methanol-phosphate buffer solution within appropriate time, which was much different from the behavior observed on native beta-cyclodextrin bonded silica. The effect of column temperature on the enantio-separation of dansyl D,L-Phe with GCDS was examined. The results show that the enantio-separation ability of the GCDS decreases with the increase of the column temperature. Other factors such as methanol concentration and pH of the mobile phase influencing the retention behavior of solutes on the GCDS are also discussed.

Amino Acids↗

PubMed2000

[Advances of capillary electrophoresis and capillary electrochromatography using ionic coating column].

Capillary electrochromatography (CEC) is a promising micro-separation technique, which combines the high selectivity of HPLC and the high efficiency of HPCE. In comparing to CE with fused silica capillary and CEC with ODS stationary phase, capillary electrophoresis and capillary electrochromatography with ionic coating columns can cause EOF more controllable, and provide an alternative separation mechanism. Therefore, the new CEC and CE modes are in favor of optimizing the separation and broadening the range of samples for analysis. The development of capillary electrophoresis and capillary electrochromatography using ionic coating column is reviewed with 48 references.

Amino Acids↗