ABSTRACT
In this experiment, an ultra-high performance liquid chromatographytandem triple quadrupole mass spectrometry was established for the determination of caffeine in commercially available Ginkgo Folium. The samples were extracted by ultrasonic method with methanol, and separated on Waters CORTECS T3 column(2.1 mm×100 mm, 2.7 μm), with mobile phase of 0.1% formic acid solution-0.1% formic acid acetonitrile solution for gradient elution, at flow rate of 0.3 mL·min~(-1); column temperature of 30 ℃, and injection volume of 2 μL. Mass spectrometry was conducted at ESI~+ multiple reaction monitoring(MRM) mode; quantitative analysis was conducted with external standard method. The results showed that in the range of 0.099 6-9.96 ng·mL~(-1), there was a good linear relationship between the mass concentration of caffeine and the peak area, R~2=0.999; the average recovery was 84.51%, with RSD of 6.2%. The results of precision, repeatability and stability showed that the RSD was 5.1%, 5.9%, 7.2%, respectively. The content range of caffeine in 10 batches of Ginkgo Folium was 1.52-60.86 μg·kg~(-1). In conclusion, this method is accurate, reliable and reproducible, which provides a reference for the safety study of Ginkgo Folium.
Subject(s)
Caffeine , Chromatography, High Pressure Liquid , Ginkgo biloba , Tandem Mass SpectrometryABSTRACT
To analyze the development of coronavirus disease 2019(COVID-19), this study systematically retrieved relevant Chinese and English literatures from both CNKI and Web of Science database platforms by bibliometric research method and CiteSpace 5.5.R2 software to obtain information and visualize relevant literatures. A total of 695 Chinese and 446 English literatures were included in this paper. Statistics showed that China had published most of the literatures and established close cooperation with the United States and the United Kingdom. Through the analysis, Tongji Medical College of Huazhong University of Science and Technology and its affiliated hospitals published the largest number of the publications. Moreover, the highly productive journals including Journal of Traditional Chinese Medicine and The Lancet covered eight major fields, such as medicine, medical virology, radiation medicine, infectious disease, and traditional Chinese medicine. Besides, a total of 35 special COVID-19 funds were recently established to subsidize these studies. The key words and themes analysis indicated that protein structure of COVID-19, receptor targets and mechanisms of action, integration of traditional Chinese and Western medicine, screening and development of antiviral drugs from traditional Chinese medicine and Western medicine, vaccine research as well as epidemiological characteristics and prediction are current study hotspots. This study provides a reference for researchers to rapidly master main study directions of COVID-19 and screen out relevant literatures.