Optimization of Response Surface of Ultrasonic-assisted Extraction of Rizhao Black Tea

[Objective] The aim was to determine the optimal technology for ultrasonic-assisted extraction of black tea was determined. [Method] Taking Black Tea as materials, the Box-Behnken response surface design method of tea polyphenols ultrasonic-assisted extraction process optimization was applied. The regression optimization model of the ethanol volume fraction, ultrasonic time, and ultrasonic temperature, ethyl acetate extract stalling time and tea polyphenols was established. [Result] The influence of four factors on the black tea polyphenol solvents affecting size was as follows: ultrasonic time > ethanol volume fraction > stalling extraction time > ultrasound temperature. The best extraction process was ultrasonic time 80 min, volume fraction of 88.99% ethanol, extraction time 89.97 min, ultrasonic temperature of 80 ℃. At the optimized technical parameters, the black tea phenolic extraction yield can be as high as 73.50%. [Conclusion] The study provided theoretical basis for the development of tea leaves and black tea.

电子传递链功能缺陷相关线粒体疾病的治疗进展

线粒体疾病(mitochondrial diseases, MDs)与电子传递链功能缺陷密切相关。电子传递链上的五种复合物共同维持电子传递链的正常功能,从而确保ATP的产生。电子传递链上任何一种复合物的功能缺陷都会损伤线粒体功能,导致线粒体疾病的发生。因此,针对不同的复合物功能缺陷,可以采取相应的治疗措施来挽救其功能,达到缓解或治愈线粒体疾病的目的。本文以电子传递链上五种复合物为研究对象,阐述不同复合物功能缺陷导致的线粒体疾病以及相应的治疗措施。

气相色谱-质谱联用法测定不同厂家盐酸二甲双胍缓释片中N-亚硝基二甲胺的含量

目的:建立气相色谱-质谱联用(gas chromatography-mass spectrometry,GC-MS)法测定不同厂家盐酸二甲双胍缓释片中N-亚硝基二甲胺(N-nitrosodimethylamine,NDMA)的含量。方法:采用GC-MS法,标准曲线法计算盐酸二甲双胍缓释片中NDMA的含量。色谱柱为Agilent VF-WAXms(30 m×0.25 mm,0.25μm),程序升温,以多反应监测(MRM)模式进行离子检测。结果:该方法线性范围为0.25~50.00 ng·mL-1,r=0.999 9;平均加标回收率为107.79%,RSD为3.53%;检出限为0.25 ng·mL-1。采用该方法对市面上31家企业共75批次的盐酸二甲双胍缓释片进行NDMA含量测定,2018年、2019年和2020年批次中均存在一定比例的超限。结论:该方法操作简单、灵敏、准确,适用于盐酸二甲双胍缓释片中NDMA的检测,可为其质量控制提供参考。