Simultaneous determination of amino acids in different teas using supercritical fluid chromatography coupled with single quadrupole mass spectrometry

Tea is a widely consumed beverage and has many important physiological properties and potential health benefits. In this study, a novel method based on supercritical fluid chromatography coupled with mass spectrometry (SFC-MS) was developed to simultaneously determine 11 amino acids in different types of tea (green teas, Oolong tea, black tea and Pu-erh tea). The separation conditions for the analysis of the selected amino acids including the column type, temperature and backpressure as well as the type of additive, were carefully optimized. The best separation of the 11 amino acids was obtained by adding water (5%, v/v) and trifluoroacetic acid (0.4%, v/v) to the organic modifier (methanol). Finally, the developed SFC-MS method was fully validated and successfully applied to the determination of these amino acids in six different tea samples. Good linearity (r ≥ 0.993), precision (RSDs≤ 2.99%), accuracy (91.95%-107.09%) as well as good sample stability were observed. The limits of detection ranged from 1.42 to 14.69 ng/mL, while the limits of quantification were between 4.53 and 47.0 ng/mL. The results indicate that the contents of the 11 amino acids in the six different tea samples are greatly influenced by the degree of fermentation. The proposed SFC-MS method shows a great potential for further investigation of tea varieties.

Calculating single layer production contribution of heavy oil commingled wells by analysis of aromatic parameters in whole-oil GC-MS

Traditional fluid production profile logging is not usually suitable for heavy-viscous crude oil wells.Biodegradation of heavy oil can lead to the loss of n-alkanes,and the use of chromatogram fingerprint techniques in studying the production contributions of single layers in heavy oil commingled wells has limitations.However,aromatic compounds are relatively well preserved.We took the heavy oil commingled wells of small layers NG55 and NG61 in the ninth area of the Gudong oil field as examples.Based on the principle of chromatography,the whole-oil GC-MS was used,and the aromatic parameters which have a strongly linear relationship with the ratio of mixed two end member oils were verified and selected in laboratory.Studies showed that the ratio of （1,4,6-＋ 2,3,6-trimethylnaphthalene） to 1,2,5-trimethylnaphthalene has a strongly linear relationship with the ratio of the mixed two end member oils （R2=0.992）.The oil contributions from single layers NG55 and NG61 in six commingled heavy oil wells were calculated using established charts and this relationship.The calculated results are consistent with the results of long period dynamic monitoring and logging interpretation in the study area and can provide a scientific basis for monitoring production performance and hierarchical management of reservoirs.The study provides a new geochemical method for calculation of the contributions of single layers in heavy oil commingled wells when conventional fluid production profile logging is not suitable.

Moments of Inertia, Magnetic Dipole Moments, and Electric Quadrupole Moments of the Lithium Isotopes

The single-particle Schrödinger fluid model is designed mainly to calculate the moments of inertia of the axially symmetric deformed nuclei by assuming that each nucleon in the nucleus is moving in a single-particle potential which is deformed with time t, through its parametric dependence on a classical shape variable α(t). Also, the Nilsson model is designed for the calculations of the single-particle energy levels, the magnetic dipole moments, and the electric quadrupole moments of axially symmetric deformed nuclei by assuming that all the nucleons are moving in the field of an anisotropic oscillator potential. On the other hand, the nuclear superfluidity model is designed for the calculations of the nuclear moments of inertia and the electric quadrupole moments of deformed nuclei which have no axes of symmetry by assuming that the nucleons are moving in a quadruple deformed potential. Furthermore, the cranked Nilsson model is designed for the calculations of the total nuclear energy and the quadrupole moments of deformed nuclei which have no axes of symmetry by modifying the Nilsson potential to include second and fourth order oscillations. Accordingly, to investigate whether the six p-shell isotopes 6Li, 7Li, 8Li, 9Li, 10Li, and 11Li have axes of symmetry or not, we applied the four mentioned models to each nucleus by calculating their moments of inertia, their magnetic dipole moments, and their electric quadrupole moments by varying the deformation parameter β and the non-axiality parameter γ in wide ranges of values for this reason. Hence for the assumption that these isotopes are deformed and have axes of symmetry, we applied the single-particle Schrödinger fluid model and the Nilsson model. On the other hand, for the assumption that these isotopes are deformed and have no axes of symmetry, we applied the cranked Nilsson model and the nuclear super fluidity model. As a result of our calculations, we can conclude that the nucleus 6Li may be assumed to be deformed and has an axis of symmetry.

大气压固体分析探针结合单四极杆质谱仪快速检测18种合成大麻素

本研究建立了一种大气压固体分析探针结合单四极杆质谱仪(ASAP-MS)快速检测18种合成大麻素(SCs)的方法。通过优化ASAP-MS锥孔电压,确定4种优化电压为15、25、35和50 V,以提供化合物全面的质谱信息。在优化条件下对一系列SCs标准溶液进行分析,建立了18种SCs的质谱库,并对本方法进行方法学验证,得到18种SCs的检出限为10~20 mg/L。应用该方法对缴获的15批次未知样品进行检测,9批次呈阳性。该方法具有前处理简单、分析速度快、匹配高效精准、定性准确的优势,可用于基层公安禁毒部门的分析检测。

基于四极质谱仪航天器单点检漏应用研究

本文介绍了航天器单点检漏过程中3种常见的单点模型,并依据航天器泄漏设计指标对单点模型的示漏气体浓度进行分析计算。根据现有的四极质谱仪装置GAM500对单点模型进行试验验证,试验说明四极质谱仪可测漏率满足航天器漏率设计指标要求,可以应用在航天器单点检漏工艺中。

铁棍山药和太谷山药代谢成分差异研究

采用代谢组学方法,利用超高效液相色谱-单四极杆-飞行时间质谱仪对铁棍山药和太谷山药的代谢成分进行分析,以期为山药的功能评价提供参考。结果表明,利用Masslynx软件能将铁棍山药和太谷山药正离子模式下检测到的代谢物进行很好的分组,这表明,铁棍山药和太谷山药代谢物差异较大;进一步对其差异代谢物质进行S-Plot分析,发现有8种差异代谢物质,通过数据库比对,其中3种为植酸、麦角甾醇和豆固醇,分别属于酸类和醇类,有5种代谢物需要进一步鉴定。由此可见,通过对山药代谢物的差异化分析,可以对山药的药效属性进行评估,这为保持山药的地道性提供了重要的检测手段。

单四极杆气质联用仪的结构、故障诊断及日常维护

主要介绍了单四级杆气质联用仪的结构,各部件在日常使用中的要求以及容易出现的故障问题,并以Thermo Fisher Trace 2000DSQII为例介绍了对气质联用仪的故障诊断及日常维护工作。

解吸电晕束电离源质谱法快速检测食品包装材料中的双酚A

采用解吸电晕束电离源（DCBI）与质谱联用法测定食品包装材料中的双酚A。优化了萃取溶剂和离子源等参数。DCBI优化后，甲醇为萃取溶剂，检测模式为负离子模式，电离电压为-2kV，离子传输管温度225℃，He气体流速1．0L/min。当选用全扫描的模式时，单个样品测定时间小于30s，对双酚A的检出限为0．1mg／L，在1—100mg／L浓度范围内线性良好，相关系数达到0．98，直接检测食品包装材料中的双酚A时，平均回收率为94％～125％，测定结果的相对标准偏差（RSD）小于17％。本方法分析速度快，灵敏度高，基体影响小，适用于大量样品快速检测。

血清中尿酸和尿素含量测定的超高效液相色谱–单四级杆质谱法国际比对

基于单四极杆质谱建立了血清中尿酸、尿素含量准确测定的同位素稀释超高效液相色谱–质谱方法,并以该方法参加了国际物质量咨询委员会(CCQM)组织的"血清中尿酸尿素含量测定"的K、P国际比对。血清样品用乙腈除去蛋白质,分别采用C18反相柱和电喷雾(ESI)负离子模式检测尿酸、CN正相柱和ESI正离子模式检测尿素,同位素稀释的单点校准法进行定量,用3种标准物质(GBW 09157,GBW 09169,NIST SRM 909c)进行方法验证,测量比对血清样品(Ⅰ,Ⅱ)获得国际等效一致性。该方法操作简单、快速准确,适用于血清中尿酸尿素的定量分析。

Single-particle resonances in a deformed relativistic potential

The positive-parity single-neutron levels in an axially-deformed relativistic quadrupole Woods-Saxon potential are analyzed. Neutron states are obtained as the solutions of the corresponding single-particle Dirac equation, using the coupled-channels method in the coordinate space. The evolution of the levels close to the continuum threshold and, in particular, the occurrence of singleneutron resonant states as the functions of the axial deformation parameter 0 β 0.5, are examined using the eigenphase representation. Calculations are performed for different values of the radius of the potential (R/r 0 ) 3 , corresponding to a variation of the mass number A.

162.5MHz RFQ加速器的单束团选择

CiADS加速器装置核物理实验终端提出了单束团的需求,为此在CiADS超导直线加速器原型样机II的低能传输段上展开了单束团筛选的计算与模拟。原型样机Ⅱ的射频四极场(Radio-Frequency Quadrupole,RFQ)加速器采用的频率是162.5 MHz,对应单束团脉宽6.15 ns。加载常规常电压的斩波器下降沿接近20 ns,无法做到6.15 ns的稳定无场区域,因此采用在斩波器的偏转板上加载正负交替变化的线性电压设计方法来筛选单束团。计算结果表明:当电压变化斜率为201.8 V·ns^(−1)时,对于20 keV的质子束,可以筛选出6.15 ns的单束团进入RFQ加速器进行下级传输。多粒子模拟结果表明:实现了低能段传输效率为80.7%,RFQ传输效率为54.4%,整体传输效率为43.9%。

利用核电四极矩检测含氮爆炸物

介绍了利用核电四极矩检测含氮爆炸物的理论、系统组成及工作原理，并把多单脉冲用于含氮爆炸物的检测。

气相色谱–质谱法快速测定客家黄酒中的醇类物质

建立一种无需样品前处理,直接进样快速测定客家黄酒中醇类物质的方法。将样品溶液用0.22μm滤膜过滤后,直接进样到单四极杆气相色谱–质谱仪中,采用全扫描模式测定。结果在客家黄酒中鉴定出醇类化合物9种,采用外标法建立标准曲线对其中的甲醇、丙醇、异戊醇、异丁醇进行定量分析,4种醇的质量浓度在1~100μg/mL范围内与对应的色谱峰面积均呈良好的线性,线性相关系数为0.9527~0.9969,检出限为0.5~2μg/mL。6次重复测定结果的相对标准偏差为0.4%~3.1%,加标回收率为94.3%~99.8%。该方法简便快速,满足客家黄酒中醇类物质日常快速检测的要求。

液相色谱-单四级杆法检测奶粉中泛酸的应用

随着水解乳清蛋白原料在婴幼儿食品中的开发利用,给奶粉中泛酸检测造成了巨大的困难。开发本方法旨在解决水解蛋白对检测的干扰问题。奶粉样品经温水溶解、调节pH值、沉淀蛋白后,采用HSS T3液相色谱柱法分离,以10 mmol/L乙酸铵溶液(含0.5%甲酸)和甲醇为流动相进行梯度洗脱,电喷雾离子化后由单四极杆质谱检测,同位素内标法定量。结果表明:方法定量限为0.0141 mg/100 g,线性范围内低、中、高3个标准添加水平的回收率为92.0%~102.7%,相对标准偏差在0.31%~2.23%;本检验方法与国标法对于羊奶粉、牛奶粉基质样品中泛酸成分的测定结果无显著差异。该方法操作过程简单、分析周期短、灵敏度高、重复性好,适用于特殊医学配方奶粉、婴幼儿配方奶粉中泛酸的测定,尤其对添加水解蛋白的奶粉样品具有理想的定量效果,具有极大应用前景。

ICP-MS/MS测定镍基高温合金中痕量金、汞和硒的质谱干扰消除

采用单四极杆质谱(ICP-MS)无法消除第二代镍基单晶高温合金CMSX-4中合金元素Ta,W,Ni及载气Ar所形成的多原子离子对痕量杂质元素Au,Hg和Se产生的质谱干扰。本研究基于三重四极杆-电感耦合等离子体质谱(ICP-MS/MS)技术,通过考察不同碰撞/反应模式(No Gas模式、He模式、O_(2)原位质量模式、O_(2)质量转移模式)下的质谱干扰消除效果,建立了CMSX-4中痕量杂质元素Au,Hg和Se的测定方法。结果表明,采用O_(2)原位质量模式能够有效消除Ta O^(+)对Au^(+)和WO^(+)对Hg^(+)的质谱干扰;采用O_(2)质量转移模式能够消除Ni O^(+)和ArAr^(+)对Se^(+)的质谱干扰。综合考虑3种待测元素的信号强度及背景等效浓度,确定O_(2)流速为0.60 m L/min。通过考察内标元素对基体效应的校正效果,选择^(133)Cs为测定Au和Hg的内标元素、^(103)Rh为测定Se的内标元素。在优化条件下,建立了Au,Hg和Se的工作曲线,线性相关系数均为0.9991,方法检出限为0.11~0.29 ng/m L。分别对3个添加水平的镍基高温合金样品独立测定9次,相对标准偏差(RSD)为2.0%~9.5%。Au和Hg的加标回收率为96.1%~107.2%。采用本方法对镍基高温合金有证标准物质中的Se的质量浓度进行测定,经t检验表明测定结果与标准值无显著性差异。

探索四极形变和单粒子共振态在N=28壳闭核^(40)Mg中的作用

共振在许多物理现象的形成中起着至关重要的作用.本文首先介绍了单粒子共振态的研究意义和研究方法,其次详细阐述了复动量表象(CMR)方法在研究奇特核方面的优势,最后介绍了极其丰中子核^(40)Mg的研究意义.^(40)Mg的基态表现得像一个单中子晕.为了弄清导致这种晕现象的原因,如大的形变或零势能面附近的共振态等.本文采用CMR方法探讨了^(40)Mg的弱束缚结构,计算了随四极形变演化的束缚态与共振态的能量及宽度.结果显示,p-f轨道反转、幻数N=28消失和一定的形变存在.本文还进一步分析了价中子所占能级主要组分的占比、密度分布和波函数,发现^(40)Mg是一个由p-波配置主导的长椭晕核.这一晕现象可能源自强的四极相关和混合p-f轨道驱动的长椭形变,使得具有低-l组分的单粒子态数量增加.这些发现揭示了弱束缚态或连续谱中的低-l组分轨道有助于晕的形成.本发现对进一步探索更多奇特核中晕特征与形变效应和连续谱耦合之间的关系是必要的.

利用场发射显微镜研究O_2对单壁碳纳米管场发射的影响

利用场发射显微镜和四极质谱计研究了充入高纯O2 的四极质谱和O2 对单壁碳纳米管场发射的影响 .单壁碳纳米管经过约 10 0 0℃的热处理得到清洁态场发射像后 ,充入O2 ,分别测量了O2 吸附和脱附后场发射的I V特性 .实验观测到在单壁碳纳米管上O2 的吸附使场发射电流减小 ,说明逸出功增加 .在 10 - 4 Pa的O2 压强下对单壁碳纳米管进行约 10 0 0℃的热处理 ,可以产生氧化刻蚀作用 ,观测到场发射像的变化 ,并测量了氧化刻蚀产生的I

Revisiting the sex pheromone of the fall armyworm Spodoptera frugiperda,a new invasive pest in South China

The fall armyworm Spodoptera frugiperda is a worldwide serious agricultural pest,and recently invaded South China.Sex pheromone can be employed to monitor its population dynamics accurately in the field.However,the pheromone components previously reported by testing different geographic populations and strains are not consistent.On the basis of confirming that the S.frugiperda population from Yunnan Province belonged to the com strain,we analyzed the potential sex pheromone components in the pheromone gland extracts of females using gas chromatography coupled with electroan-tennographic detection(GC-EAD),gas chromatography coupled with mass spectrometry(GC-MS)and electroantennography(EAG).The results show that(Z)-9-tetradecenal acetate(Z9-14:Ac),(Z)-11-hexadecenyl acetate(Z11-16:Ac),(Z)-7-dodecenyl acetate(Z7-12:Ac)or(E)-7-dodecenyl acetate(E7-12:Ac)with a ratio of 100:15.8:3.9 induced EAD responses to varying degrees:Z9-14:Ac elicited a strong EAD response,Z7-12:Ac or E7-12:Ac elicited a small but clear EAD response,while Z11-16:Ac elicited a weak EAD response.Further single sensillum recording(SSR)showed that Z9-14:Ac and Z7-12:Ac induced dose-dependent activities in two types(A and B)of sensilla in male antennae,respectively,while the sensilla in response to E7-12:Ac and Z11-16:Ac was not recorded.Finally,wind tunnel tests reveal that Z9-14:Ac and Z7-12:Ac are two principal sex pheromone components of the tested population.

一测多评法同时测定没食子药材及制剂西帕依固龈液中5个没食子鞣质

目的:建立同时测定没食子药材及制剂西帕依固龈液中没食子酸(GA)、1-没食子酸酰葡萄糖(1-GG)、没食子酸甲酯(MG)、1,2,3,6-四没食子酰葡萄糖(TeGG)和1,2,3,4,6-五没食子酰葡萄糖(PGG)5个没食子鞣质的一测多评方法(QAMS)。方法:采用超高效液相色谱-四极杆-飞行时间质谱(UPLC-Q-TOF MS)法,对没食子药材的主要没食子鞣质进行定性鉴别,并确定待测成分;采用HPLC建立多成分同步测定方法,色谱柱为Phenomenex C_(18)柱(250 mm×4.6 mm,5μm),流动相为乙腈(A)-0.2%磷酸溶液(B),梯度洗脱(0~20 min,3%A→8%A;20~30 min,8%A→10%A;30~70 min,10%A→15%A;70~100 min,15%A→18%A;100~120 min,18%A→30%A),流速1.0 mL·min^(-1),柱温35℃,检测波长275 nm。以GA为内参物,采用斜率法,分别建立1-GG、MG、TeGG、PGG的相对校正因子(RCFs),并考察其耐用性。采用QAMS法和外标法(ESM)分别计算和比较9批次没食子药材和3批次西帕依固龈液中上述没食子鞣质的含量,以验证QAMS法的准确性和可行性。结果:从没食子中定性鉴别出GA、1-GG、MG、TeGG和PGG 5个含量较高且具有良好生物活性的没食子鞣质,选择作为HPLC定量分析的指标性成分。GA、1-GG、MG、TeGG和PGG的线性范围分别为8.13~520、6.25~400、8.28~530、9.00~576、9.00~576μg·mL^(-1)。1-GG、MG、TeGG和PGG的RCFs分别为1.75、0.95、1.12、1.25,对不同HPLC仪、色谱柱、流速和柱温的耐用性良好(RSD≤5.00%)。采用QAMS法测得9批次没食子药材中GA、1-GG、MG、TeGG和PGG的含量范围分别为3.69%~5.07%、1.26%~1.98%、14.0%~17.4%、19.8%~25.3%、5.93%~9.24%,3批次西帕依固龈液中GA、1-GG和MG的含量范围分别为1.89~2.40、0.0750~0.105、0.874~1.12 mg·mL^(-1)。QAMS法和ESM法测定的含量结果的相对误差均小于3.5%,无显著性差异。结论:以GA为内参物,建立的上述5个没食子鞣质的QAMS法,简便、准确、可靠,节省大量对照品,可用于没食子药材及制剂西帕依固龈液的定量分析及质量控制。

Recent advances in proteomics and metabolomics in plants

Over the past decade,systems biology and plant-omics have increasingly become the main stream in plant biology research.New developments in mass spectrometry and bioinformatics tools,and methodological schema to inte-grate multi-omics data have leveraged recent advances in proteomics and metabolomics.These progresses are driv-ing a rapid evolution in the field of plant research,greatly facilitating our understanding of the mechanistic aspects of plant metabolisms and the interactions of plants with their external environment.Here,we review the recent progresses in MS-based proteomics and metabolomics tools and workflows with a special focus on their applications to plant biology research using several case studies related to mechanistic understanding of stress response,gene/protein function characterization,metabolic and signaling pathways exploration,and natural product discovery.We also present a projection concerning future perspectives in MS-based proteomics and metabolomics development including their applications to and challenges for system biology.This review is intended to provide readers with an overview of how advanced MS technology,and integrated application of proteomics and metabolomics can be used to advance plant system biology research.