Showing papers by "Jian Ni published in 2016"

Chemical Constituents from Daphne giraldii Nitsche and Their Contents Simultaneous Determination by HPLC.

Abstract: Daphne giraldii Nitsche (Thymelaeaceae) is widely distributed in the Chinese provinces of Shaanxi, Gansu, and Qinghai, which has been used in Chinese folk medicine to treat ache and rheumatism. Pharmacologic tests have revealed that the plant has anti-inflammatory, analgesic, and anticancer activities. However, there is still not enough systemic investigation on the chemical constituents and the method for the contents simultaneous determination in D. giraldii. Therefore, the isolation and characterization of the compounds from the stem barks of this plant were reported. Moreover, a facile, accurate, and reliable method has been developed and validated for their simultaneous determination using HPLC-DAD.

Simultaneous Analysis of Quercetin and Naringenin in Rat Plasma by Liquid Chromatography–Tandem Mass Spectrometry: Application to a Pharmacokinetic Study After Oral Administration

Abstract: A rapid and specific LC-MS-MS method has been developed for simultaneous analysis of quercetin and naringenin in rat plasma. The method was applied to the pharmacokinetics studies of quercetin and naringenin after oral administration of Pollen Typhae extract. The samples were prepared by the protein precipitation method. The analysis was carried out on an ACQUITY UPLC™ BEH C18 column with gradient elution using mobile phase, which included acetonitrile and water (containing 0.1% formic acid). The flow rate was 0.4 mL/min. All analytes including internal standard (IS) were monitored by selected reaction monitoring with an electrospray ionization source. Linear responses were obtained for quercetin ranging from 0.5 to 100 ng/mL and naringenin ranging from 5 to 1000 ng/mL. The intra- and interday precisions (RSD) were less than 10.78 and 11.20%. The extraction recovery of the analytes was acceptable. Stability studies showed that quercetin and naringenin were stable in the preparation and analytical process. The validated method was successfully used to determine the concentration-time profiles of quercetin and naringenin.

Types, Principle, and Characteristics of Tandem High‐Resolution Mass Spectrometry and Its Applications

Abstract: Tandem high-resolution mass spectrometry (THRMS) is an analytical technique that has arisen in recent years and is now widely used in pharmaceutical research and development (RD for example, for the identification of constituents in herbs and formulae, pharmacokinetics, omics, and drug degradation), food safety, environmental contamination and other research fields. Time of Flight (TOF) and Orbitrap are the most widely used mass analysers in THRMS, and the technical specifications vary among the different types of THRMS and even among the different manufacturers for a given type of analyser. In this article, we review the principle and functional characteristics of different types or models for THRMS and provide a brief description of its applications in the medical research, food safety, and environmental protection fields.