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Yiping Liao

Publications and source records attributed to Yiping Liao.

5 recordsLinked to original sources
PubMed2004

Determination of dissociation constants of pharmacologically active xanthones by capillary zone electrophoresis with diode array detection.

In this article, the dissociation constants (pKa) of 10 pharmacologically active xanthones isolated from herbal medicine Securidaca inappendiculata were determined by capillary zone electrophoresis with diode array detection. The pKa values determined by the method based on the electrophoretic mobilities (calculated from migration times) have been proved by the method based on UV absorbance calculated from the online spectra corresponding peaks. No conspicuous difference was observed between the two methods with acceptable reproducibility. Two pKa values (pKa1 and pKa2) were found for four xanthones while generally the 10 compounds possess the pKa values ranging from 6.4 to 9.2.

Electrophoresis, Capillary↗
PubMed2004

Rapid determination of aristolochic acid I and II in Aristolochia plants from different regions by beta-cyclodextrin-modified capillary zone electrophoresis.

Chinese herbs nephropathy (CHN) is a kind of severe kidney disease caused by excessively taking aristolochic acid (AA). Hence, it is essential for health security and quality control of related herbal medicines to develop an efficient method for separation and determination of these two important components in Traditional Chinese Medicines. In this study, a rapid capillary zone electrophoresis (CZE) method using 120 mM sodium borate buffer containing 10 mM beta-cyclodextrin (beta-CD) as modifier was firstly developed for the analysis of AA-I and AA-II within 4min in some medicinal plant samples. The separation conditions including pH of running buffer, CD content in the buffer system, applied voltage and capillary temperature were systematically optimized, and two kinds of aristolochic acids in 37 herbal samples of Aristolochia plants were successfully determined with high separation efficiency, satisfactory sensitivity, repeatability and recovery. The result indicated high variability in the contents of aristolochic acids due to different species and regions. The comparison of CZE method with high performance liquid chromatography (HPLC) was also discussed.

Algorithms↗
PubMed2004

[Study on thermostability and photo-isomerization of trans-resveratrol by high performance liquid chromatography and liquid chromatography-electrospray ionization-mass spectrometry].

The thermostability and photo-isomerization reaction mechanism of trans-resveratrol were studied by using high performance liquid chromatography (HPLC) and liquid chromatography-electrospray ionization-mass spectrometry ( LC-ESI-MS). A reversed-phase Hypersil-ODS column was used with the mobile phase consisting of 60/40 methanol-water, with addition of 0.05% trifluoroacetic acid for HPLC, and 0.1% formic acid and 5 mmol/L ammonium formate for LC-ESI-MS, at a flow rate of 0.5 mL/min. Diode array detection was set at 300 nm and the injection volume was 20 or 10 microL. Mass spectrometric conditions were in the negative mode. The results of thermostability test under 4, 20 and 40 degrees C indicated that the concentration of trans-resveratrol, after storage for 600 h, was decreased slightly under 4 degrees C, decreased by 5% under 20 degrees C, and 10% under 40 degrees C. In addition, the photo-isomerization reaction of trans- and cis-resveratrol under 254 nm and 365 nm UV irradiation was investigated by LC-ESI-MS, showing that the isomerization is based on p-status, and that some secondary reactions are radical induced.

Chromatography, High Pressure Liquid↗