在线净化/液相色谱-四极杆/静电场轨道阱高分辨质谱法快速筛查水产品中123种兽药残留

建立了快速筛查水产品中123种兽药残留的在线净化/液相色谱-四极杆/静电场轨道阱高分辨质谱检测方法,兽药涵盖15类123种(20种磺胺类、6种大环内酯类、16种喹诺酮类、12种β-激动剂、17种苯并咪唑类、4种四环素类、2种镇静剂、6种激素、4种β-内酰胺类、1种氨苯砜、2种抗球虫药、2种染料、24种糖皮质激素、1种氯...     

色谱-质谱联用技术在我国3种柚子组分鉴定及指纹图谱建立中的应用

利用色谱-质谱联用技术对我国主要的3个品种柚子果实的不同部位(外表皮、内表皮、内果皮、果肉、种子)的化学组分进行结构鉴定及种类和含量的差异性分析,结果表明,沙田柚、琯溪蜜柚、玉环柚果实5个部位共鉴定出68种不同化学组分物质,包括醇类19种、酯类15种、烯烃类9种、有机酸类8种、酮类7种、烷烃类4种、其他物质6种。其中3个品种柚子外表皮共有的化学组分有7种,含量最高的是柠檬烯(44.03%);内表皮共有的化学组分有6种,含量最高的是油酸酰胺(44.62%);内果皮共有的化学组分有10种,含量最高的是谷甾醇(30.75%);果肉共有的化学组分有11种,含量最高的是软脂酸(20.02%);种子中共有的化学组分有15种,含量最高的是亚油酸(45.83%)。化学组分差异性分析结果表明,沙田柚、琯溪蜜柚、玉环柚3种柚子的外表皮独有的化学组分分别有3种、6种、4种,内表皮分别有3种、4种、8种,内果皮分别有1种、4种、6种,果肉分别有4种、4种、2种,沙田柚、玉环柚种子独有的化学组分均为1种,并对化学组分进行聚类分析和相似度分析。研究结果说明不同品种柚子同一部位的化学组分种类和含量均存在相似性和差异性,特有物质较多,色谱指纹图谱特异性显著,这可为柚类品种鉴定、品质质量控制、原产地溯源等提出一种新的色谱指纹图谱思路。     

合欢鲜花香气挥发物成份研究

采用循环吹气吸附法捕集合欢鲜花头香,经溶剂冼脱后用GC/MS/DS联用技术和气相色谱双柱程序升温保留指数辅助定性分析鉴定出其中的25种成份,它们是单萜烯3种、芳烃1种、烯烃1种、含氮化合物2种、含氧化合物18种(其中醇8种、醛酮3种、酯5种、脂肪酸1种、环醚1种)。主要成份为反-氧化芳樟醇(呋喃型)、α-罗勒烯、顺-氧化芳樟醇(吡喃型)、芳樟醇、异戊醇和4-戊烯-2-酮。嗅觉鉴定的结果表明,合欢鲜花的主要赋香成份为反-氧化芳樟醇(呋喃型)、芳樟醇、异戊醇、α-罗勒烯和2,2,4-三甲基恶丁烷。     

同时蒸馏萃取-气相色谱/质谱法分析烟草中挥发性成分

本文对云南12种烟叶中挥发性成分进行提取分离,气相色谱/质谱测定.系统地对同时蒸馏萃取条件和色谱分离条件进行优化,结合谱库检索和匹配度定性方法鉴定149种化合物,并对其中的35种重要香气成分进行了定量分析,包括酮类7种、醇类6种、烯烃类4种、烟碱类3种、烷烃类2种、醛类2种、酯类2种、呋喃类2种等.该方法具有81.09％～97.45％的高回收率.结果表明,同时蒸馏萃取集采样、萃取、浓缩于一体,操作简单快速,适合于烟草中挥发性成分的提取,结合气相色谱/质谱联用仪(GC-MS)分离测定,能准确对挥发性成分进行定性和定量分析.     

干黄芪中挥发性成分的提取与分析

为了确定干黄芪的特征香气成分,采用同时蒸馏萃取法对干黄芪中的挥发性成分进行提取,并考察了原料用量、浸泡时间和提取时间三个因素对结果的影响。在较优条件下对干黄芪中的挥发性成分进行提取,提取物通过GC-MS分析,结合计算保留指数和NIST11谱库检索,共鉴定出65种挥发性成分,其中包括醛类20种、醇类9种、烃类7种、酚类5种、酯类5种、杂环类5种、酮类4种、酸类2种、其他类8种。其中正己醛、2-戊基呋喃、丁香酚、正己醇、1-辛烯-3-醇、糠醛等挥发性成分对干黄芪的特征香气贡献较大。     

固相微萃取结合气-质联用分析侧柏叶中的挥发性成分

以产自河北的侧柏叶为原料,采用四种固相微萃取纤维对其中的挥发性成分进行提取,用气质联用进行分析,共分离出112种成分,采用质谱与保留指数进行定性,鉴定出87种成分(四种萃取纤维的提取物中都鉴定出的成分有59种),其中烯烃类51种(以单萜和倍半萜为主),烷烃类4种,芳香烃类3种,醇类18种,醛酮类3种,酯类4种,醚类3种,吡嗪类1种;另外采用质谱初步定性出12种。采用面积归一化法确定了它们的相对含量,含量较高的有(1R)-(+)-α-蒎烯、(+)-3-蒈烯、D-柠檬烯、β-水芹烯、δ-松油烯、β-榄香烯、石竹烯、顺式-罗汉柏烯、葎草烯、大根香叶烯D、δ-杜松烯、柏木脑等。对比所得结果可以发现,CAR/PDMS(85μm)的萃取纤维对侧柏叶中挥发性成分的提取效果较好。     

萝卜炖牛腩挥发性风味成分的分离与鉴定

采用固相微萃取(solid-phase micro extraction,SPME)法和溶剂辅助蒸发(solvent-assisted flavor evaporation,SAFE)法提取萝卜炖牛腩中的挥发性风味成分,利用气相色谱-质谱联用(gas chromatography-mass spectrometry,GC-MS)技术对其挥发性风味成分进行分析。对影响固相微萃取的操作条件萃取头纤维种类、样品量、吸附温度以及萃取时间进行了优化,结果表明当选择65μm PDMS/DVB(粉色)萃取头、样品量为8 g、吸附温度为60℃、萃取时间为40 min时,萃取效果最佳。两种方法共鉴定出98种挥发性成分,包括烃类11种、醛类13种、酮类11种、酸类7种、醇类22种、酯类12种、醚类4种、酚类6种、含硫含氮及其他杂环化合物12种。其中,醛类、醚类和含硫含氮及其他杂环化合物可能对萝卜炖牛腩特征风味的形成有着重要的影响。     

固相萃取-气相色谱-质谱联用同时测定河水和海水中87种农药

采用固相萃取-气相色谱-质谱联用技术,建立了河水和海水中87种农药(24种有机磷、15种有机氯、12种唑类、9种拟除虫菊酯类、5种氨基甲酸酯类、7种酰胺类及15种其他新型农药)的多残留同时分析方法。优化了影响分离效果和灵敏度的仪器参数,考察了固相萃取柱柱型及水样体积、pH、盐度的影响,采用NH2柱优化了净化效果,内标法和替代物法用于数据的质量控制。结果表明: 在最佳条件下,各目标农药的方法检出限为0.1～6.6 ng/L;以实际河水和海水为基底,在5 ng/L和20 ng/L的加标水平下,绝大多数目标农药的回收率为60%～120%,相对标准偏差(n=4)为0.01%～9.7%。该法灵敏、准确,已成功地应用于福建九龙江河口区表层水样中多种类农药的复合污染监测,检出包括5种有机磷类、3种酰胺类、4种唑类、3种氨基甲酸酯类、2种拟除虫菊酯类等农药20种。     

火焰原子吸收法测定三种天然色素中的八种无机元素

用火焰原子吸收光谱法测定了三种色素中常见的八种微量无机元素Zn、Fe、Ca、Cu、K、Na、Mn、Mg的含量。结果表明，三种色素中K、Mg、Ca含量较高，Cu含量较低。讨论了几种无机元素与健康的关系，对开发这三种天然色素提供了有用的参考数据。     

张裕XO级白兰地挥发性成分的提取分离与鉴定

建立了一套对白兰地挥发性物质进行预处理的方法,并采用气相色谱-质谱法(GC-MS)较全面地鉴定了白兰地的挥发性成分。实验先采用液-液萃取方法提取张裕XO级白兰地的挥发性成分,然后将酸性成分与碱性和中性成分分离,再采用柱色谱分离手段将其分离为若干个级分并浓缩,采用气相色谱-质谱、标准品比对、保留指数(RI)值比较等方法对分离得到的各级分中的成分进行了鉴定,在白兰地中共鉴定出302种挥发性成分,包括醇30种、醛酮类35种、酸类20种、酯类104种、苯同系物及其衍生物24种、酚类14种、缩醛14种、呋喃类16种、萜烯类22种和其他物质23种。结果表明,采用这套预处理方法能将白兰地的挥发性成分较有效地分组和浓缩。     

国内光催化研究进展简述

分1975~1985, 1985~1995和1995~2012三个时期简要介绍了国内光催化研究进展, 主要侧重于光催化材料及其改性、应用和反应机理方面的研究进展, 并指出了当前光催化领域存在的一些重要问题和未来的发展趋势, 涉及到光解水、CO₂还原、环境净化和选择性有机合成等方面.     

Interpretation of inorganic arsenic metabolism in humans in the light of observations made in vitro and in vivo in the rat

The toxicity of inorganic trivalent arsenic for living organisms is reduced by in vivo methylation of the element. In man, this biotransformation leads to the synthesis of monomethylarsonic (MMA) and dimethylarsinic (DMA) acids, which are efficiently eliminated in urine along with the unchanged form (As_i). In order to document the methylation process in humans, the kinetics of As_i, MMA and DMA elimination were studied in volunteers given a single dose of one of these three arsenicals or repeated doses of As_i. The arsenic methylation efficiency was also assessed in subjects acutely intoxicated with arsenic trioxide (As₂O₃) and in patients with liver diseases. Several observations in humans can be explained by the properties of the enzymic systems involved in the methylation process which we have characterized in vitro and in vivo in rats as follows: (1) production of As_i metabolites is catalyzed by an enzymic system whose activity is highest in liver cytosol; (2) different enzymic activities, using the same methyl group donor (S-adenosylmethionine), lead to the production of mono- and di-methylated derivatives which are excreted in urine as MMA and DMA; (3) dimethylating activity is highly sensitive to inhibition by excess of inorganic arsenic; (4) reduced glutathione concentration in liver moderates the arsenic methylation process through several mechanisms, e.g. stimulation of the first methylation reaction leading to MMA, facilitation of As_i uptake by hepatocytes, stimulation of the biliary excretion of the element, reduction of pentavalent forms before methylation, and protection of a reducing environment in the cells necessary to maintain the activity of the enzymic systems.     

Reactions in droplets in microfluidic channels

Fundamental and applied research in chemistry and biology benefits from opportunities provided by droplet-based microfluidic systems. These systems enable the miniaturization of reactions by compartmentalizing reactions in droplets of femoliter to microliter volumes. Compartmentalization in droplets provides rapid mixing of reagents, control of the timing of reactions on timescales from milliseconds to months, control of interfacial properties, and the ability to synthesize and transport solid reagents and products. Droplet-based microfluidics can help to enhance and accelerate chemical and biochemical screening, protein crystallization, enzymatic kinetics, and assays. Moreover, the control provided by droplets in microfluidic devices can lead to new scientific methods and insights.     

Recent Advances in Analytical Methodology for in vivo Electrochemistry in Mammals

Electrochemistry is one of the most advanced techniques for monitoring neurochemical activities in the living brain because electrochemical approaches bear the advantageous features of high spatial and temporal resolutions, which facilitate its tremendous potential in investigating the highly spatially heterogeneous brain system and the fast dynamics of neurochemical activities. On the other hand, since brain is the most complicated organ in the sense of its numerous kinds of neurochemical species, high selectivity is always required for any analytical methods that approach the brain. In this review, we will discuss various electrochemical methodologies to achieve selective detection of neurochemicals in mammalian brain and the strategies developed mainly by our group towards selective monitoring of both electrochemically active and inactive neurochemicals. At the end, we will discuss possible solutions towards brain mapping of neurochemical species and combination of neurochemical detection strategy with electrophysiology as the direction of future development of electroanalysis in living brain.     

青蒿素研究进展

青蒿素是目前治疗疟疾的特效药。本文对自青蒿素发现以来的最新研究进展进行了比较详尽的综述。内容包括: 青蒿素的发现及历史, 青蒿素的来源, 青蒿素的全合成,青蒿素的生物合成, 青蒿素衍生物以及植物组织培养生产青蒿素。     

Recent Advances in Polymer Flooding in China

Polymer flooding is drawing lots of attention because of the technical maturity in some reservoirs. The first commercial polymer flooding in China was performed in the Daqing oilfield and is one of the largest applications in the world. Some laboratory tests from Daqing researchers in China showed that the viscoelasticity of high molecular weight polymers plays a significant role in increasing displacement efficiency. Hence, encouraged by the conventional field applications and new findings on the viscoelasticity effect of polymers on residual oil saturation (ROS), some high-concentration high-molecular-weight (HCHMW) polymer-flooding field tests have been conducted. Although some field tests were well-documented, subsequent progress was seldom reported. It was recently reported that HCHMW has a limited application in Daqing, which does not agree with observations from laboratory core flooding and early field tests. However, the cause of this discrepancy is unclear. Thus, a systematic summary of polymer-flooding mechanisms and field tests in China is necessary. This paper explained why HCHMW is not widely used when considering new understandings of polymer-flooding mechanisms. Different opinions on the viscoelasticity effect of polymers on ROS reduction were critically reviewed. Other mechanisms of polymer flooding, such as wettability change and gravity stability effect, were discussed with regard to widely reported laboratory tests, which were explained in terms of the viscoelasticity effects of polymers on ROS. Recent findings from Chinese field tests were also summarized. Salt-resistance polymers (SRPs) with good economic performance using produced water to prepare polymer solutions were very economically and environmentally promising. Notable progress in SRP flooding and new amphiphilic polymer field tests in China were summarized, and lessons learned were given. Formation blockage, represented by high injection pressure and produced productivity ability, was reported in several oil fields due to misunderstanding of polymers’ injectivity. Although the influence of viscoelastic polymers on reservoir conditions is unknown, the injection of very viscous polymers to displace medium-to-high viscosity oils is not recommended. This is especially important for old wells that could cause damage. This paper clarified misleading notions on polymer-flooding implementations based on theory and practices in China.     

Advances in passive sampling in environmental studies

Passive sampling is based on the phenomenon of mass transport due to the difference between chemical potentials of analytes in a given environmental compartment and the collection medium inside a dosimeter. The subsequent laboratory procedure (i.e. extraction, identification and determination of analytes) is the same as in the case of classic sampling techniques.Passive sampling techniques are characterized by simplicity with regard to the dosimeter's construction as well as its maintenance. Therefore, they find ever increasing application in the field of environmental research and analytics. When choosing a passive sampling method, one should not forget that some passive samplers require the time-consuming calibration step before being used in the field.Novel solutions and modifications of existing sampler designs have been presented. Practical application of passive dosimetry in environmental analytics, including sampling of water, soil, air and other atypical media are discussed. Some aspects of calibration methods in passive dosimetry are also described. The latest trends in the application of passive sampling are highlighted.     

我国化学生物学研究新进展

作为化学领域的一门新兴二级学科,化学生物学已经成为具有举足轻重作用的交叉研究领域,是推动未来生命和化学学科发展的重要动力。近年来,我国的化学生物学研究正在以前所未有的速度蓬勃发展,在基础建设、人才培养、研究经费支持等方面都有了长足的进步。尤其是以国家自然科学基金委"基于化学小分子探针的信号转导过程研究"重大研究计划为依托,我国的化学生物学工作者以小分子探针为工具,充分发挥化学与生命科学等多学科综合交叉的优势,对细胞信号转导中的重要分子事件和机理进行了深入的探索,在一些前沿方向上取得了突出的成绩,相关研究结果多次发表在顶级的国际期刊上。本文对近两年来我国化学生物学领域取得的突出进展加以归纳和介绍:(1)基于小分子化合物及探针的研究。利用有机化学手段,通过设计合成一系列多样化的小分子化合物,以这些探针为工具深入开展了细胞生理、病理活动的调控机制、细胞关键信号转导通路及重要靶标、抑制剂和标记物的发现、基于金属催化剂的活细胞生物分子激活等方面的研究;(2)以化学生物学技术为手段,着重发展了针对蛋白质、核酸和糖等生物大分子的合成、特异标记与操纵方法,用以揭示这些生物大分子所参与的生命活动的调控机制;(3)采用信号传导过程研究与靶标发现相结合,以实现"从功能基因到药物"的药物研发模式,发展了药物靶标功能确证与化合物筛选的联合研究策略;(4)以化学分析为手段,发展了在分子水平、细胞水平或活体动物水平上,获取生物学信息的新方法和新技术。这些研究成果极大地推动了我国化学生物学的进步。共引用63篇参考文献。     

我国理论化学2008年研究进展简述

2008年中国大陆理论化学工作者在多个领域的研究都取得了新进展. 这些领域包括密度泛函理论的方法和应用、化学动力学和反应势能面的构造、光化学反应动力学、生物分子及生命现象、立体化学等. 本文简述了2008年中国大陆理论化学方面的研究工作进展, 重点突出了几个引起国际同行广泛关注的亮点.     

水相中金属有机化学反应的研究进展

本文综述了近年来水相中金属有机化学反应的研究进展, 讨论了该类反应在反应机理、试剂及立体化学等方面的特点, 以及在天然产物全合成和工业生产等方面的应用。