A Sensitive Reversed-Phase High-Performance Liquid Chromatography Method for the Quantitative Determination of Milk Xanthine Oxidase Activity

A new reversed-phase high performance liquid chromatography method was developed to quantitate the activity of xanthine oxidase involved in milk fat globule membrane with xanthine as the substrate and the separation of product (uric acid). The increment of uric acid in the reaction system was used to calculate the total activity of XO. The optimized assay conditions, linearity of detection, recovery of uric acid and chromatogram were developed in text, indicating this method is simple, rapid and efficient. It is an alternative potential method for the determination of the activity of XO in milk.

变异胰岛素症

变异胰岛素症是在糖尿病患者中发现的分子病。对变异胰岛素的研究是近年在胰岛素结构与功能,临床医学和分子遗传学方面的新课题。本文就变异胰岛素的发现及其特点、变异胰岛素的鉴定技术以及变异胰岛素与糖尿病的关系作一综述。

Isolation and purification of uremic middle molecules by multi-step liquid chromatography

Isolation and comparison of uremic sera and urine and normal sera and urine were performed by gel permeation chromatography, anion exchange chromatography and re-versed-phase high performance liquid chromatography. Two uremic middle molecular fractions (A and B) were obtained from uremic sera and urine and normal urine by gel permeation chromatography, but not from normal sera. The anion exchange chromatographic results of fraction A from different origins demonstrate that subfraction A-3 could be excreted in urine by healthy subject, but accumulated in uremic serum for renal failure of patient with uremia. After desalinization subfraction A-3 was analyzed by MALDI-TOF-MS. The results show that subfraction A-3 consists of six compounds with molecular weight 839, 873, 1007.94, 1106, 1680 and 2015 respectively. Finally, by reversed-phase high performance liquid chromatography, subfraction A-3 was further resolved into six independent fractions. Thus, the isolation and purification of six middle molecular

Separation and Measurement of Three Kinds of Endogenous Hormones in Rhizome of Alhagi sparsifolia

[ Objective] The aim was to establish effective method for endogenous hormone extraction and explore conditions of chromatographic analysis for three endogenous hormones in rhizome of Alhagi sparsifolia. [ Methed ] Activol （GA3 ）, zeatin （ZR） and indole-3-acetic acid （IAA） in rhizome were separated and measured as per RP-HPLC. [Result] The average recovery rates of GA3, ZR and IAA were 98.3%, 90.3% and 101.3%, respectively, indicating that the method is suitable for quantitative analysis with little errors. The chromatographic conditions were as follows： methanol/0. 75% of acetic acid at 45：55 （mobile phase） ; flow speed at 0.7 ml/min; wavelength at 254 nm; column temperature at 25 ℃. [Conclusion] The research preliminarily established HPLC conditions for separation of endogenous hormones in rhizome of Alhagi sparsifolia.

Effects of Different Drying Methods on Content of Paederosidic Acid in Paederia scandens

[Objectives]To establish a method to simultaneously determine the content of paederosidic acid in Paederia scandens dried by four different methods.[Methods]Reversed-phase high performance liquid chromatography(RP-HPLC)was adopted.The chromatographic column:Thermo SCIENTIFIC Hypersil GOLD Dim.(mm);mobile phase:acetonitrile-0.1%phosphoric acid aqueous solution;gradient elution;column temperature:30℃;flow rate:1 mL/min;detection wavelength:236 nm;injection volume:10μL.[Results]The linear range of the detection injection volume of paederosidic acid was 0.64-9.60μg(R=0.9992);the limit of quantity(LOQ)was 5.10 ng,and the limit of detection(LOD)was 1.36 ng;the RSD of the precision,stability and reproducibility test was all less than 3%;the sample recovery rate was 98.87%,RSD<3.00,n=6.The results show that the content of paederosidic acid in the shade-dried P.scandens is the highest,and the order of the content is P.scandens(dry in shade)>P.scandens(dried at 50℃)>P.scandens(dried at 60℃)>P.scandens(dried at 70℃).[Conclusions]This method is sensitive,reliable and reproducible,and can be used to simultaneously determine the content of paederosidic acid in P.scandens dried by four different methods.

反相高效液相色谱法测定淫羊藿中淫羊藿苷的含量

目的建立用于测定淫羊藿中淫羊藿苷含量的反相高效液相色谱法。方法采用ZORBAX Ecilpse XDB-C_(18)(150 mm×4.6 mm,5μm)色谱柱;以水-乙腈(74:26,V/V)为流动相;检测波长270 nm;流速1.0 mL·min^(-1),柱温25℃。结果淫羊藿苷质量浓度在5～50 mg·L^(-1)内与其峰面积之间线性关系良好(r=0.999 9),平均加样回收率为100.32%,RSD为0.44%。结论本方法操作简便、快速,结果准确,可用于淫羊藿中淫羊藿苷的含量测定。