硫酸长春地辛及其注射剂有关物质检查方法的改进

以反相高效液相色谱法检测硫酸长春地辛及其注射剂中的有关杂质。分离条件：色谱柱为Ｃ１８柱,流动相为Ｖ（甲醇）Ｖ（体积分数为１．５％的二乙胺溶液,用磷酸调节ｐＨ至７．５）＝７０３０。杂质分离情况良好。     

键合偶联双奎宁手性固定相的制备和手性拆分性能

键合偶联双奎宁手性固定相的制备和手性拆分性能;手性固定相;奎宁;高效液相色谱;拆分     

A new strategy for the discovery of epimedium metabolites using high-performance liquid chromatography with high resolution mass spectrometry

In this paper, a new strategy of drug metabolite discovery and identification was established using high-performance liquid chromatography with high resolution mass spectrometry (HPLC–HRMS) and a mass spectral trees similarity filter (MTSF) technique. The MTSF technique was developed as a means to rapidly discover comprehensive metabolites from multiple active components in a complicated biological matrix. Using full-scan mass spectra as the stem and data-dependent subsequent stage mass spectra to form branches, the HRMS and multiple-stage mass spectrometric data from detected compounds were converted to mass spectral trees data. Potential metabolites were discovered based on the similarity between their mass spectral trees and that known compounds or metabolites in a mass spectra trees library. The threshold value for match similarity scores was set at above 200, allowing approximately 80% of interference to be filtered out. A total of 115 metabolites of five flavonoid monomers (epimedin A, epimedin B, epimedin C, icariin, and baohuoside I) and herbal extract of epimedium were discovered and identified in rats via this new strategy. As a result, a metabolic profile for epimedium was obtained and a metabolic pathway was proposed. In addition, comparing to the widely used neutral loss filter (NLF), product ion filter (PIF), and mass defect filter (MDF) techniques, the MTSF technique was shown superior efficiency and selectivity for discovering and identifying metabolites in traditional Chinese medicine (TCM).     

盐酸特拉唑嗪降解产物的结构鉴定

盐酸特拉唑嗪是一种新型选择性 α₁-肾上腺能受体拮抗剂,用于治疗高血压和良性前列腺增生。采用高效液相色谱-高分辨多级质谱(HPLC-HRMSⁿ)联用法对强氧化条件下盐酸特拉唑嗪原料药的降解产物进行了详细的解析和结构确证。共检测到15种降解产物,其中7种与文献报道的有关物质相同,另外8种为新检测到的降解产物,其主要降解途径为酰胺键水解、羟基化、羰基化及3种途径组合的次级降解途径。     

克拉霉素的合成新方法

以醚化剂1-乙氧基环己烯和硅烷化试剂1,1,1,3,3,3-六甲基二硅氨烷为保护试剂, 采用醚化-硅烷化保护法制备了克拉霉素. 以红霉素A肟为原料计算, 经肟羟基醚化、2',4"-OH硅烷化、6-OH选择性甲基化、脱保护至克拉霉素, 四步反应总收率为49.5%.     

小硅藻光合作用脂13 C稳定同位素定量标记分析

以小硅藻( Nitzschia closterium f. minutissima)作为研究对象,利用超高压液相色谱联用四极杆-静电场轨道阱高分辨质谱技术,研究了处于平台期的小硅藻中的光合作用脂被13 C标记的程度和速度。结果显示：在平台期13 C人工标记的10天内,所有4类光合作用脂均被13 C明显标记,其中二酰甘油双半乳糖脂( DG-DG)、磷脂酰甘油( PG)、二酰甘油硫代糖脂( SQDG)被13 C标记的总量,从刚进入平台期到平台期第8天逐渐增加,此后出现下降趋势,在第8天分别达到最大值(173±24) ng/mg,(473±41) ng/mg 及(1224±21) ng/mg,标记率分别达到56.3%,38.4%和62.6%;而二酰甘油单半乳糖脂(MGDG)被13C标记的总量在整个平台期呈现持续上升趋势,并在第10天达到(956±51) ng/mg,标记率为87.3%。可见,不同脂质在藻体内合成的先后时间有差别,为了清晰地了解生物摄食过程中对微藻中特定脂类的同化机理,需要藻体内被13 C标记的每类脂质含量的最大化,针对DGDG、PG、SQDG,应选取标记了8天的微藻来投喂生物,而针对MGDG,则应选取标记了10天的微藻投喂生物。     

A New Method of Measurement for Elastic Wave Velocities in Minerals and Rocks at High Temperature and High Pressure and Its Significance

We developed a new method of measurement for elastic wave velocity of rocks and minerals at high temperature and high pressure in a wedge-type cubic anvil. The shear-wave and other ultrasonic wave can be identified by full wave phase analysis (FWPA), thus the velocities of compression-wave and shear-wave can be obtained in a single experiment. We have done the measurements of elastic wave velocities on pyrophyllite, etc. at high pressure (0.1—5.5 GPa) and high temperature (ambient temperature 1600℃), the ranges of the pressure and the temperature are in the head among the methods of the wave velocites measurement in laboratory in the world.     

基于高分辨质谱的甲基化心磷脂高通量分析方法的建立和应用

该文基于心磷脂标准品的甲基化反应,建立了高灵敏度高通量分析甲基化心磷脂的液相色谱 - 高分辨质谱方法。由于甲基化后的心磷脂具有特征性的碎片,因此建立了包含780个分子特征片段的模拟数据库用于脂质鉴定。衍生化后,CL（14∶0/14∶0/14∶0/14∶0）信号提高了10倍,定量下限（LOQ）达到10 ng/mL。将该方法应用于小鼠衰老过程中心磷脂的调控研究,通过Tracefinder本地二级数据库共鉴定了43个心磷脂分子,其中21个心磷脂在衰老的大脑中有差异变化。结果发现：含有FA（20∶4）、FA（22∶6）长链多不饱和脂肪酸的心磷脂在衰老过程中呈下降趋势。高分辨质谱平台为甲基化的心磷脂分析提供了一种高通量筛选方法,对于低丰度心磷脂的检测具有很大潜力。     

The Influence of the Exchange-Correlation Functional on the Non-Interacting Kinetic Energy and Its Implications for Orbital-Free Density Functional ApproximationsSCI北大核心CSCD

In this work it is shown that the kinetic energy and the exchange-correlation energy are mutual dependent on each other.This aspect is first derived in an orbital-free context.It is shown that the total Fermi potential depends on the density only,the individual parts,the Pauli kinetic energy and the exchange-correlation energy,however,are orbital dependent and as such mutually influence each other.The numerical investigation is performed for the orbital-based non-interacting Kohn-Sham system in order to avoid additional effects due to further approximations of the kinetic energy.The numerical influence of the exchange-correlation functional on the non-interacting kinetic energy is shown to be of the orderof a few Hartrees.For chemical purposes,however,the energetic performance as a function of the nuclear coordinates is much more important than total energies.Therefore,the effect on the bond dissociation curve was studied exemplarily for the carbon monoxide.The data reveals that,the mutual influence between the exchange-correlation functional and the kinetic energy has a significant influence on bond dissociation energies and bond distances.Therefore,the effect of the exchange-correlation treatment must be considered in the design of orbital-free density functional approximations for the kinetic energy.     

Stability and degradation products of imipenem applying high‐resolution mass spectrometry: An analytical study focused on solutions for infusion

Carbapenems show recognized instability in aqueous solutions; therefore some care must be taken in their handling and preparation and their use in the hospital environment. The stability and degradation products of imipenem were investigated from conditions that simulate its clinical use. For this, a simple stability‐indicating method by HPLC‐DAD was validated with a focus on the quantitation of drug concentration remaining from infusion solutions (sodium chloride 0.9% and glucose 5%). The degradation products formed were identified by high‐resolution mass spectrometry (ESI‐Q‐TOF‐MS/MS), with detection of the [M + H]⁺ ions at m/z 318 (DP‐1), m/z 599 (DP‐2) and m/z 658 (DP‐3). The most probable elemental compositions were obtained with a high degree of confidence, where the error between the masses observed and calculated was 1.25 ppm for DP‐1, ?0.33 ppm for DP‐2 and 1.82 ppm for DP‐3. The DP‐1 degradation product resulted from cleavage of the β‐lactam ring; DP‐2 corresponded to the drug dimer; and DP‐3 was generated from the interaction between imipenem and cilastatin. The proposed method provides a safe and reliable alternative for the quantitation of imipenem, and the stability data obtained by ESI‐Q‐TOF help in understanding the drug behavior under the conditions of clinical use.     

Development and validation of a high‐resolution LTQ Orbitrap MS method for the quantification of isoflavones in wastewater effluent

Isoflavones and coumestranes are the most important classes of compounds among phytoestrogens; by binding to estrogen receptors, they mimic or modulate the effect on the endogenous receptors. Little information can be found in literature about the presence of isoflavones and coumestrol in the environment, even if it is known that this may have significance, being these substances classified as endocrine disrupting compounds. In this research, we aim to explore the capabilities of the LTQ Orbitrap Discovery hybrid MS in full‐scan acquisition mode, with high resolution, to validate an analytical method for the quantification of nine isoflavones (genistein, genistin, glycitein, daidzein, daidzin, (R,S)‐equol, biochanin A, formononetin and coumestrol) in wastewater samples. The correlation coefficients of calibration curves of the nine analyzed compounds were in a range of 0.996–0.999; recoveries at two different levels of concentration (0.05 and 0.5 µg/l) were in the range 73–98%, and the limits of detection ranged between 0.0014 and 0.017 µg/l, proving that this method is sensitive enough in comparison with other methods available in literature. This method has been applied for the analysis of 20 wastewater treatment plants in County Cork, Ireland. Copyright © 2015 John Wiley & Sons, Ltd.     

QuEChERS-四极杆/静电场轨道阱高分辨质谱测定动物性食品中氟虫腈及其代谢物残留

基于低温处理和QuEChERS方法,采用超高效液相色谱-四极杆/静电场轨道阱高分辨质谱建立了动物性食品中氟虫腈及其代谢物残留的分析检测方法。样品采用乙腈提取,经低温处理,N-丙基乙二胺(PSA)和C18粉分散固相萃取(d-SPE)净化,以BEH C18色谱柱为分析柱,乙腈-0.1%乙酸溶液为流动相进行梯度洗脱分离,外标法定量。采用高分辨质谱平行反应监测(PRM)扫描模式,以负离子采集进行定性筛查和定量分析。氟虫腈及其代谢物在0.02~2μg/L和0.2~20μg/L质量浓度范围内均呈良好的线性关系,相关系数(r2)大于0.992。对液体或半液体样品(如牛奶和鸡蛋)和固体样品(如鸡肉),方法的定量下限分别为0.1μg/kg和0.2μg/kg。在不同浓度的加标水平下,氟虫腈及其代谢物在鸡蛋中的平均回收率为81.6%~96.9%,相对标准偏差(RSD)为1.3%~11.5%;在鸡肉中的平均回收率为81.2%~96.0%,RSD为3.4%~11.4%;在牛奶中的平均回收率为79.1%~100.1%,RSD为1.5%~10.7%。该方法简单、灵敏、准确,适用于动物性食品中氟虫腈及其代谢物的快速筛查和定量检测,方法的灵敏度满足欧盟的残留限量要求。     

Anomalous intensities of local mode vibrational absorption of germane and a new theoretical explanation

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An improved SPE method for fractionation and identification of phospholipids

This work reports an efficient and universal SPE method developed for separation and identification of phospholipids derived from complex biological samples. For the separation step, sequential combination of silica gel‐aminopropyl‐silica gel SPE cartridges is applied. This setup enables separation of phosphatidylcholine, lysophosphatidylcholine, phosphatidylethanolamine, phosphatidylglycerol, phosphatidic acid, phosphatidylinositol, phosphatidylserine, cardiolipin, and sphingomyelin into four fractions according to the polarity of their headgroups. Sample acquisition of the SPE fractions is performed by a high‐resolution LC‐MS system consisting of a hybrid linear IT Fourier transform ion cyclotron resonance mass spectrometer coupled to RP‐HPLC. The unequivocal advantage of our SPE sample preparation setup is avoidance of analyte peak overlapping in the determination step done by RP‐HPLC. Overlapping phospholipid signals would otherwise exert adverse ion suppression effects. An additional benefit of this method is the elimination of polar and nonpolar (e.g. neutral lipids) contaminants from the phospholipid fractions, which highly reduces contamination of the LC‐MS system. The method was validated with fermentation samples of organic waste, where 78 distinct phospholipid and sphingomyelin species belonging to six lipid classes were successfully identified.     

Refinement of the inversion‐transfer NMR experiment for faster characterization of chemical exchange

It is shown theoretically that the inversion‐transfer experiment used to estimate the value of unidirectional rate constants in chemical exchange systems can be performed faster via a reduction of the recovery delay. The chemical exchange rate constants can then be estimated accurately with a formula close to that of standard inversion transfer and easy to use, after a justified approximation. A function was developed to determine the optimal value of the recovery delay for an optimal inversion‐transfer sequence. The validity of these theoretical results was checked experimentally with a solution of N,N‐dimethylacetamide in which chemical exchange arises from internal hindered rotation. Copyright © 2015 John Wiley & Sons, Ltd.     

超高效液相色谱-静电场轨道阱高分辨质谱法测定法莫替丁及其制剂中的痕量N-亚硝基二甲胺

建立了测定法莫替丁及其制剂中N-亚硝基二甲胺(NDMA)含量的超高效液相色谱-静电场轨道阱高分辨质谱法(UHPLC-Orbitrap HRMS)。样品以甲醇作为提取溶剂,经涡旋混匀、恒温振荡、高速离心、微孔过滤后进行液相色谱-质谱(LC-MS)分析。采用ACE EXCEL 3 C₁₈-AR(150 mm×4.6 mm,3μm)色谱柱,以0.1%甲酸水溶液和0.1%甲酸乙腈为流动相梯度洗脱分离,流速为0.50 mL/min,柱温为30℃,自动进样器温度为4℃,设置六通阀切换保护质谱系统。质谱分析采用ESI离子源,正离子平行反应监测(PRM)扫描模式,外标法定量。NDMA在1.00～100.00 ng/mL范围内线性良好,相关系数(r)为0.999 7,检出限和定量下限分别为0.20 ng/mL和1.00 ng/mL,在法莫替丁及其制剂中的平均回收率为98.5%～108%,相对标准偏差(RSD)为2.3%～6.7%。将该法用于47批供试品中NDMA的测定,在1批法莫替丁原料和2批制剂中检出NDMA,其含量超过限度规定。该方法灵敏、准确、操作简便,可用于法莫替丁及其制剂...