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ABSTRACT: 3', 5' Reversed-sequence oligonucleotides are isomers with the same length and base composition, except with reversed base sequence. In the current work, 6 oligonucleotide model samples were designed to study chromatographic behaviour of 3',5' reversed-sequence isomers by optimizing effects on retention and separation. The retention factor and resolution of isomers were investigated under triethylamine-acetic acid (TEAA) concentrations of 0.025 - 0.15 mol/L, pH values of 5.0 - 6.8, temperatures of 25 - 45 degrees C and flow rates of 0.3 - 0.7 mL/min by reversed-phase ion-pair chromatography (RP-IPC). The best resolution was observed under TEAA concentration of 0.05 mol/L, pH 6.8 and flow rate of 0.4 mL/min. While the effect of temperature on the separation was not apparent, effect of initial organic strength was stronger than that of the elution gradient. The retention and separation trends of the model samples were different, and weak retention of the samples on the solid phase contributes to good separation. It is concluded that 5' end of oligonucleotide sequence showed stronger interactions with the stationary phase than the 3' end did. This research might help to understand the retention mechanism of oligonucleotides by RP-IPC.
Se pu = Chinese journal of chromatography / Zhongguo hua xue hui 12/2007; 25(6):814-9.
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ABSTRACT: Two novel neophysalins, named physalin W (1) and physalin X (2), were isolated from the EtOH extract of the aerial parts of Physalis alkekengi L. var. franchetii (Solanaceae). Their structures were determined mainly by spectroscopic techniques including 2D-NMR (HMBC, HSQC, 1H,1H-COSY, NOESY) and MS experiments.
Helvetica Chimica Acta 05/2007; 90(5):963 - 966. · 1.48 Impact Factor
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ABSTRACT: Oligodeoxynucleotides (ODNs) may possess biological activity in vivo, and are used for the cancer therapeusis. Synthesized ODNs contains many by-products, and so their purity check and resolution of single-base, i. e., the separation of ODNs differing by one nucleotide in length, become necessary. In this study, capillary zone electrophoresis (CZE) method was developed for the separation of two sets of model compounds of single-stranded oligodeoxynucleotide mixtures (18 - 20 mers), phosphodiester oligodeoxynucleotides (PO-ODNs) and their phosphorothioate modifications (PS-ODNs), with equal sequences differing in a single base. The effects of the CZE operating parameters on the separation were investigated and optimized to further improve the resolution, such as the pH values and the concentrations of running buffer, the varieties and concentrations of additives, the separation voltage as well as the temperature. It was confirmed that the pH value of the buffer played the most important role in the separation, and the urea used as the additive in the system improved significantly the resolution of PS-ODNs. Consequently, the PO-ODNs and PS-ODNs mixtures could be single-based separated on a fused-silica capillary of 50 microm x 49.0 cm (40.7 cm of effective length) under the optimum conditions: the running buffer system of 50 mmol/L NaH2PO4-H3PO4 (pH 2.24)-7 mol/L urea, the pressure injection of 2 kPa x 10 s, the separation voltage of -20 kV, the column temperature of 25 degrees C, and the ultraviolet (UV) detection at 260 nm. The average resolutions for the separation of 18 - 19 mers and 19 - 20 mers of PO-ODNs were 4.68 and 3.20, respectively; and the average resolutions for the separation of 18 - 19 mers and 19 - 20 mers of PS-ODNs were 1.23 and 0.81, respectively. The relative standard deviations of the migration time and the resolution were all less than 5%. This method will be useful for the qualification of PO-ODNs and PS-ODNs samples as they are used in antisense drug development due to the relatively easy operation and good reproducibility of the method in comparing with the capillary gel electrophoresis.
Se pu = Chinese journal of chromatography / Zhongguo hua xue hui 02/2007; 25(1):101-6.
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ABSTRACT: A replaceable capillary gel electrophoretic (replaceable CGE) method was developed for the separation of two sets of model compounds of single-stranded oligodeoxynucleotide mixtures (18-20 mers), phosphodiester oligodeoxynucleotides (PO-ODNs) and their phosphorothioate modifications (PS-ODNs), with equal sequences differing in a single base. Polyethylene glycol (PEG) 35000 was chosen as the sieving matrix. It was confirmed that PEG polymer solution less influenced resolutions of the PS-ODNs compared with those of the PO-ODNs, while acetonitrile used as an additive in the system improved the separation significantly. It was also noticed that the effect of temperature on separation was much larger than that of denaturant urea.
Journal of Chromatography B 12/2006; 843(2):334-8. · 2.89 Impact Factor
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ABSTRACT: The contents of cytidine, adenosine, guanosine and uridine in Banlangen Injections were determined by capillary zone electrophoresis. Shorter fused silica capillary (32.5 cm x 50 microm i. d. with effective length of 23.5 cm) was used. The samples were analyzed with 60 mmol/L borate-10% (v/v) 2-propanol-20% (v/v) acetonitrile running buffer at 20 kV voltage (25 degrees C capillary temperature). Pressure injection of 1 kPa x 10 s was employed, and the detection wavelength was 254 nm. Factors of the electrophoresis condition were investigated, such as the kinds and concentration of the electrolyte, buffer pH value, the type and concentration of organic modifier, separation voltage and temperature. The samples were filtered through 0.45 microm membrane, then direct injection was employed. External calibration of peak area versus concentration was used in the determination. Linear calibrations of four nucleosides were obtained within 12.5 - 250 mg/L (r > 0.999 1). The limits of detection (mg/L) were 6.2 of cytidine, 4.6 of adenosine, 6.7 of guanosine, and 9.0 of uridin. The average recoveries of the four nucleosides were between 95.1% - 102.3% with RSDs of 0.3% - 4.9%. The method is simple, rapid, reproducible and accurate. It can be used for the routine analysis of the four nucleosides in Banlangen Injections.
Se pu = Chinese journal of chromatography / Zhongguo hua xue hui 10/2004; 22(5):539-42.
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ABSTRACT: The Pearson product-moment correlation coefficient is being used to evaluate the similarity of the high-performance liquid chromatographic fingerprints of traditional Chinese medicine (TCM) in China. It is confirmed that a large range of peak areas produced the wrong results. A new algorithm concerning weighted Pearson product-moment correlation coefficient is proposed in this article. The results for both real cases and simulated data sets show that the weighted Pearson product-moment correlation coefficients allow relatively larger differences for large values, smaller differences for small values, and more reliable results than the unweighted Pearson product-moment correlation coefficients. Weight selection depends on the specific scientific problem.
Journal of chromatographic science 42(10):545-50. · 0.88 Impact Factor
