Simultaneous identification of the three active constituents in Lung-Ventilating-Regulating Oral Liquid by RP-HPLC.

The study aimed to develop a HPLC method for ephedrine, hesperidin, and baicalin in Lung-Ventilating-Regulating Oral Liquid. The three active constituents were identified in an Agilent TC-C18 (2) chromatographic column (250mm × 4.6mm, 5µm), with 0.2% phosphoric acid solution - methyl cyanides as mobile phase, which was performed at a gradient elution column temperature of 25oC and a flow rate of 0.8 mL•min-1. Then the eluate was detected at detection wavelengths of 207 nm (for ephedrine) and 278 nm (for hesperidin and baicalin). Under the chromatographic conditions, ephedrine, hesperidin, and baicalin were well separated, which showed good linear relationships at 0.158-2.370, 0.164-4.100 and 0.160-4.000µg, respectively. The coefficients of recovery of these three kinds of samples showed 100.2%, 98.7% and 97.8%, respectively. The developed method is convenient, accurate and well repeatable, and consequently can be applied for the quality control of Lung-Ventilating-Regulating Oral Liquid.

Genesis analysis of high-gamma ray sandstone reservoir and its log evaluation techniques: a case study from the Junggar basin, northwest China.

In the Junggar basin, northwest China, many high gamma-ray (GR) sandstone reservoirs are found and routinely interpreted as mudstone non-reservoirs, with negative implications for the exploration and exploitation of oil and gas. Then, the high GR sandstone reservoirs' recognition principles, genesis, and log evaluation techniques are systematically studied. Studies show that the sandstone reservoirs with apparent shale content greater than 50% and GR value higher than 110API can be regarded as high GR sandstone reservoir. The high GR sandstone reservoir is mainly and directly caused by abnormally high uranium enrichment, but not the tuff, feldspar or clay mineral. Affected by formation's high water sensitivity and poor borehole quality, the conventional logs can not recognize reservoir and evaluate the physical property of reservoirs. Then, the nuclear magnetic resonance (NMR) logs is proposed and proved to be useful in reservoir recognition and physical property evaluation.

[Fast determination of andrographolide and dehydroandrographolide in Xiaoyanlidan Tablets by microemulsion electrokinetic chromatography].

A microemulsion electrokinetic chromatography (MEEKC) method for the determination of andrographolide and dehydroandrographolide in Xiaoyanlidan Tablets was established. The MEEKC method involved the use of sodium dodecyl sulfate (SDS) as surfactant, ethyl acetate as organic solvent and 1-butanol as co-surfactant. The effects of several factors such as the acidity and concentration of borate buffer, SDS and 1-butanol contents were investigated. The optimized composition (by mass) of microemulsion system are 0.5% ethyl acetate--0.6% SDS--6.0% 1-butanol--92.9% 30 mmol/L sodium tetraborate buffer (pH 9.5). This system allowed a useful and reproducible separation of the analytes to be achieved in less than 6 min. The proposed method is a simple, fast and sensitive method for the determination of andrographolide and dehydroandrographolide in Xiaoyanlidan Tablets.

Rapid separation and determination of resibufogenin and cinobufagin in toad venom and Liushen tablet by beta-cyclodextrin modified micellar electrokinetic chromatography.

A rapid cyclodextrin modified micellar electrokinetic chromatography (CD-MEKC) method was proposed for the determination of resibufogenin and cinobufagin in the Chinese herbal extracts from toad venom and its medicinal preparation (Liushen tablet). The two components have the close structural similarity and similar hydrophobicity, which result in poor resolution in normal MEKC. The addition of neutral beta-CD to the MEKC system was found to improve the separation of the studied compounds. The effects of several CD-MEKC parameters on the resolutions were evaluated systematically. Based on the investigation, a background electrolyte solution consisting of 10 mM borate buffer adjusted to pH 8.5, 40 mM sodium dodecyl sulfate (SDS), 12 mM beta-CD and 10% (v/v) of methanol was found to be optimal conditions for the fast separation. The contents of resibufogenin and cinobufagin were successfully determined within 5 min, with satisfactory repeatability and recovery.