大气CH_4中碳稳定同位素组成的PreCon-GC/C-IRMS系统测定

利用预浓缩装置-气相色谱/燃烧-同位素比值质谱仪(PreCon-GC/C-IRMS)联用系统,建立了就采样、浓缩和在线质谱分析大气CH4中稳定碳同位素组成的测定方法。通过多组试验对比,分析并讨论了利用PreCon-GC/C-IRMS联用技术测定大气CH4中碳稳定同位素比值的试验条件、系统线性、稳定性及准确度和精密度等。结果表明,在本研究方法条件下,当离子流强度在1.0~20 V时,系统线性良好(斜率S=0.04‰/V),在4.0~15 V内其线性(斜率S=0.03‰/V)优于总体线性;系统测量稳定性可靠,δ13C值的测定结果的S.D<0.3‰,最大偏差<0.5‰,回收率达99.99%,准确度和精度均符合分析与研究要求。利用该系统对室内和室外草坪地空气中CH4的碳稳定同位素组成做初步测试,其碳同位素的平均值分别为-31.358‰和-33.085‰,且相同地点区域空气中CH4的1δ3C值,在1 d内和不同日期间的变化均在0.5‰以内,重现性良好。

水、土壤及植物样品中1,2,4-三氯苯的提取和GC测定

<正> 1 引言三氯苯(1,2,4-TCB)是化学工业和合成农药的重要原料,但同时也是环境中广泛存在的污染物。早在1979年,1,2,4-TCB就被美国环保局列入129种优先控制的污染物之一。在我国1,2,4-TCB也是常见的一种有机污染物。水体和土壤中1,2,4-TCB的分析方法国内已见报道。但这些方法大多步骤复杂、操作困难,而且费时、试剂消耗量大。另外,目前尚没有植物样品中1,2,4-TCB分析方法的报道。本文建立了步骤简单、易操作、节约试剂的水、土壤、植物和作物籽实中1,2,4-TCB的提取和分析方法。

Studies on alkaloids binding to GC-rich human survivin promoter DNA using positive and negative ion electrospray ionization mass spectrometry

Electrospray ionization mass spectrometry (ESI-MS) was used to investigate the binding of 13 alkaloids to two GC-rich DNA duplexes which are critical sequences in human survivin promoter. Negative ion ESI-MS was first applied to screen the binding of the alkaloids to the duplexes. Six alkaloids (including berberine, jatrorrhizine, palmatine, reserpine, berbamine, and tetrandrine) show complexation with the target DNA sequences. Relative binding affinities were estimated from the negative ion ESI data, and the alkaloids show a binding preference to the duplex with higher GC content. Positive ion ESI mass spectra of the complexes were also recorded and compared with those obtained in negative ion mode.

Studies of the intermolecular DNA triplexes of C+center dot GC and T center dot AT triplets by electrospray ionization Fourier-transform ion cyclotron resonance mass spectrometry

Formation and stabilities of four 14-mer intermolecular DNA triplexes, consisting of third strands with repeating sequence CTCT, CCTT, CTT, or TTT, were studied by electrospray ionization Fourier-transform ion cyclotron resonance mass spectrometry (ESI-FTICR-MS) in the gas phase. The gas-phase stabilities of the triplexes were compared with their CD spectra and melting behaviors in solution, and parallel correlation between two phases were obtained. In the presence of 20 mm NH4+ (pH 5.5), the formation of the TTT triplex was not detected in both solution and the gas phase.

哈士蟆油中脂肪酸的GC、GC-MS分析

用气相色谱(GC)与气相色谱—质谱(GC-MS)联用技术对哈士蟆油中的脂肪酸组成进行了定性与定量分析，共鉴定出10种脂肪酸并用气相色谱法作了定量，对所得的结果进行了讨论。

单叶蔓荆子挥发油成分的GC/MS分析

采用气相色谱／质谱（ＧＣ／ＭＳ）联用技术对山东泰山产单叶蔓荆子挥发油的化学成分进行了分析，分离出３０多个峰，确认了其中２８种成分，占总离子流的９５％以上，并对挥发油的主要化学成分Δ３－蒈烯，用气相色谱／傅里叶红外光谱（ＧＣ／ＦＴＩＲ）法进行了验证。

INVESTIGATION OF METALLOPORPHYRIN MODIFIED HOPG AND GC ELECTRODES BY SCANNING TUNNELING MICROSCOPE

HOPG and GC electrode surface feature modified with Cobaltmethyltetraphenylorphyrins (CoTPP) was investigated by scanning tunneling microscope combined with cyclic voltammograms. The effect of electrode surface morphologie

二甲基乙氧基乙烯基硅烷等离子体聚合物的的GC/MS研究

本文应用色谱—质谱(GS/MS)及裂解色谱质谱(Py/GC/MS)研究了二甲基乙氧基乙烯基硅烷(VDMES)等离子体聚合的气体冷凝物及聚合物膜。鉴别出多种化合物,并推导了等离子体聚合的反应历程,进而得到了气相反应与表面反应的实验依据。

INVESTIGATION OF ELECTROCHEMICAL-BEHAVIOR OF ARS ON GC ELECTRODE BY SPECTROELECTROCHEMISTRY WITH LOPTLC

The electrochemical behavior of Alizarin Red S(ARS) on GC electrode has been studied in acidic condition by spectroelectrochemistry with LOPTLC. It was found that there are three electrochemical reactions and followed by a chemical reaction of ARS in the potential range of 1.00——0.60V. The mechanism of electrode reactions has been studied and suggested based on the informations obtained from electrochemical and insitu spectroelectrochemical experiments.

Cloning and sequence analysis of the partial sequence of the rbcL from Bryopsis hypnoides

The partial sequence of the rbcL from Bryopsis hypnoides, including the sequences of the upstream, extron and partial intron, was amplified by PCR and their sequences were determined. With Spinacia oleracea as the outgroup, neighbor-joining method and maximum parsimony method were used respectively to build phylogenetic trees according to the rbcL exon sequence among 13 species that were the typical species of six phyla. Two kinds of trees showed clearly that there were two groups among those species, the green lineage and the non-green lineage. And the relationships of algae in the green lineage were similar in the two trees but those in the non-green lineage were not consistent. Analysis of codon preference indicated that the codon preference of the rbcL exon of Bryopsis hypnoides distinctly differed from that of the relevant sequence of photosynthetic bacteria.

Concentrations and distribution of organochlorine pesticides in shellfish from Changjiang estuary

To analyze and evaluate the status of organochlorine pollutants in the Changjiang (Yangtze River) estuary and adjacent waters, the concentrations of hexachlorocyclohexane (HCHs) and dichlorodiphenyltrichloroethane (DDTs) in shellfish collected in study area from 2006 to 2007 were determined with gas chromatography (GC). The concentration range of HCHs was (ND-12.13)x10(-3) mg/kg wet weight and averaged at 0.54x10(-3) mg/kg while the concentration of DDTs was in the range of (4.06-281.73) x10(-3) mg/kg with a mean of 57.52x10(-3) mg/kg in the survey areas. The concentrations of DDTs in the shellfish were higher than HCHs', so that DDTs could be considered as typical organochlorine pollutants in the areas. The concentrations of DDTs in the shellfish were higher than HCHs', so that DDTs could be considered as typical organochlorines pollutants. The HCHs in all the shellfish conformed to the first level of criterion (0.02 mg/kg) of the Marion Biology Quality (GB 18421-2001), and that of DDTs in most samples were beyond the first level (0.01 mg/kg) but conformed to the second level (0.10 mg/kg). On average, alpha-HCH and delta-HCH occupied the most part of HCHs, while O,P'-DDT and P,P'-DDT occupied the most part of DDTs. The concentrations of organocholorine pesticides in shellfish samples varied in site and in species. The highest level occurred at the Shengsi (SS), followed by Yangkougang (YKG), Lvsi (LS), Dongyuan (DY) and Beibayao (BBY), low concentrations were observed at Changsha (CS), Beidaodi (BDD), and Gouqi (GQ). The concentration of HCHs and DDTs in most sites decreased clearly from 2006 to 2007 except for YKG, DY, BDD, LYS, and SS. All of above results suggested that the study area was slightly affected by organochlorine pesticide, special by DDTs.

GC-MS法测定藏木香栽培品种挥发油的化学成分

[目的]基于气相色谱-质谱（GC-MS）法测定藏木香栽培品种挥发油的化学成分。[方法]采用水蒸气蒸馏法从藏木香栽培品种中提取挥发油,并用GC-MS联用仪对其挥发油的化学成分进行研究。[结果]分离并确认了37种成分,其主要成分是桉叶油二烯5,11（13）-内酯-8,12,异-榄香烯,异-喇叭烯,桉叶油二烯4,11（13）-内酯-8,12。[结论]分析获得的主要化学成分及其功效为藏木香这一天然药用植物资源的人工规范化栽培和进一步综合开发利用提供了科学依据。

藏药帕朱胶囊超临界CO_2萃取成分的GC-MS分析

目的：分析治疗胃病常用的藏成药帕朱胶囊（寒水石,诃子,石榴子,胡椒,荜拔等）的主要化学成分。方法：采用超临界CO_2萃取方法提取帕朱胶囊的可溶性成分,并用气相色谱-质谱联用法对提取部位进行化学成分分析,峰面积归一化法计算各组分的相对含量。结果：共分离鉴定了22种化合物,主要成分含量为胡椒碱44.2%、亚油酸21.1%、甲基-甲撑基奥-异丙烯内酯10.5%、棕榈酸4.8%和γ-羟基-榄香烯酸内酯3.5%等。结论：藏药帕朱胶囊的主要化学成分为胡椒碱和亚油酸,两者含量共占全部提取物的65.3%

藏药材石榴籽超临界CO_2萃取成分的GC-MS分析

目的：用新方法提取藏药材石榴籽油,并对其进行化学成分分析,为石榴籽的药理研究和应用提供实验依据。方法：采用超临界CO_2萃取方法提取石榴籽的可溶性成分,并用气相色谱-质谱联用法对提取部位进行化学成分分析,峰面积归一化法计算各组分的相对含量。结果：共分离鉴定了10种化合物,主要成分含量为亚油酸40.0%、油酸22.7%、棕榈酸17.5%、硬脂酸9.0%及共轭亚油酸5.7%。结论：藏药材石榴籽的主要化学成分为亚油酸和油酸,两者含量共占全部提取物的62.7%。