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1

A validated RP-HPLC method for quantitative determination of related impurities of cholic acid bulk drugs

Sheng Z., Ye R., Ge S., Wang C., Xu X., Zhang G., Luo P.

Acta Chromatographica

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2018

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Vol. 30, no. 2

114--118

EN

An efficient and convenient reversed-phase high-performance liquid chromatography method has been developed and validated for the quantitative determination of cholic acid bulk drugs and their related impurities. Chromatographic separation was performed on a YMC-Pack ODS-AQ column (250 mm × 4.6 mm, S-5 μm, 12 nm), and the mobile phase consisted of acetonitrile, methanol, and diluted formic acid solution (pH 2.5) at a flow rate of 1.0 mL/min. The analytes were monitored using a refractive index detector at 30 °C, and the column temperature was 30 °C. Under the above chromatographic conditions, the method has good specificity and specified impurities can be effectively separated. The proposed method is found to have linearity in the 2.0–80.0 μg/mL concentration range with correlation coefficients of not less than 0.9999. The compounds analyzed in the solutions are stable for at least 7 days, and spike recoveries for all specified impurities range from 91.3% to 109.3% with relative standard deviations (RSDs) not more than 7.3%. The limit of detection and the limit of quantification for the analytes are 0.060 μg/mL and 2.0 μg/mL, respectively. The proposed method can be applied in the quality control assay of cholic acid bulk drugs, with the advantages of simplicity, accuracy, robustness, good selectivity, and high sensitivity.

2

High genetic diversity in the naturally rare plant Taihangia rupestris Yu et Li (Rosaceae) dwelling only cliff faces

Tang M., Yu F., Jin X., Ge S.

Polish Journal of Ecology

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2010

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Vol. 58, nr 2

241-248

EN

Cliffs are the primary habitat of many rare and endangered plant species, but few studies have investigated the genetic diversity of these species. Taihangia rupestris Yu et Li (Rosaceae) is the only species of the genus Taihangia, which occurs exclusively in small crevices on the faces of north-facing vertical cliffs at altitudes ranging from 600 to 1500 m above sea level. It is a perennial herb endemic to the southern part of the Taihang Mountains in northern China. We sampled fresh leaves from 11 to 38 individuals of T. rupestris in each of eight cliff-face populations located in the provinces of Hebei, Shanxi and Henan in China. The leaves were dried by silica gel and DNA was extracted. We then assessed the genetic variability within and among the eight populations of T. rupestris using random amplified polymorphic DNA (RAPD). Within the 150 plants sampled, 81.2% of the 117 RAPD markers detected were polymorphic, and Nei.s diversity (H) was on average 0.21 in the eight populations and 0.28 in the species as a whole. The grouping of the eight populations by clustering analysis agreed with their pattern of geographical distribution and with the separation of the species into two varieties (T. rupestris var. ciliata and T. rupestris var. rupestris). Genetic distances ([Phi]st) were significantly correlated with geographic distances. Although significant genetic differentiation existed between groups (varieties) and among populations, a high proportion (65.4%) of the total genetic variation was maintained within populations. Therefore, high genetic diversity is preserved in the cliffdwelling populations, and in situ protection of T. rupestris should focus on the protection of the habitat of both varieties, which may be of particular importance for the long-term survival of this species.

3

Novel method for sensitive determination of Pd2+ and its selective extraction based on Pd2+ - calcein complex

Sun X., Ge S., Li B.

Chemia Analityczna

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2009

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Vol. 54, No. 4

761-771

EN

A fluorescence quenching method for sensitive determination of Pd2+ based on complex formation between Pd2+ and calcein (Cal) was developed. The influence of surfactants and inorganic salts on the fluorescence intensity of Cal-Pd2+ complex was examined. It was found that the change in the fluorescence intensity of Cal before and after interaction with Pd2+ was linearly related to Pd2+ concentration in the range 0.0001-0.08 μg mL2+ with detection limit of 0.0001 &mu g mL-1. In the presence ofphosphate. Pd2+-Cal complex could be extracted from a liquid to solid phase using a liquid-solid extraction system comprising Tween 80 and brine, so that Pt4+ were left in brine. K2+HPO2KH2PO4 concentration ratio, pH, and concentrations of Cal and Tween 80 were adjusted to assure selective extraction. Practical applications of the method were demonstrated by successful extraction of Pd2from waste catalyst solution in the presence of high concentration of Pt(IV).

PL

Opracowano czułą metodę oznaczania Pd2+ opartąna tworzeniu kompleksu z kalceiną (Cal) i pomiarze tłumienia fluorescencji tego kompleksu. Badano wpływ związków powierzchniowo czynnych i soli nieorganicznych na natężenie fluorescencji kompleksu Cal-Pd2ł. Stwierdzono, że zmiana fluorescencji Cal zależy w sposób liniowy od stężenia Pd2+ w roztworze w zakresie stężeń palladu 0,0001-0,08 ugmL-1, 7. granicą detekcji 0,0001 μ g mL-1. W obecności fosforanów można było wyekstrahować kompleks Pd2+-Cal z fazy ciekłej do fazy stałej przy zastosowaniu układu ekstrakcyjnego ciecz-ciało stałe, zawierającego Tween 80 i solankę, tak że Pt(IV) pozostawała w solance. Selektywną ekstrację uzyskano przez odpowiednie dobranie stosunku 2HPO4KH2PO4, pH, oraz stężeń Cal i Tween 80. Praktyczne zastosowanie metody zademonstrowano poprzez skuteczne wyekstrahowanie Pd2 z roztworu odpadowego z produkcji katalizatorów w obecności dużych stężeń Pt(IV).