气相色谱-质谱法分析木屑浸提物

提出了气相色谱-质谱法分析木屑浸提物。将所选取的58种树种的木屑样品经甲醇提取,所得提取液分别用DB-FFAP色谱柱分离,在全扫描模式下作质谱分析。试验结果表明:根据TIC色谱图的特征峰中相对含量最高的组分的碳链结合方式的不同,可将上述树种分为开链烃、环烃、杂环三大类化合物。此外,对58种树种木屑样品中含量较高的5个组分的质谱分析结果的研究,发现其中有13种常见的化合物,有24种化合物为不同树种的特征组分。在此基础上,根据某树种相对含量较高的组分的碳链结合方式的不同,可对其树种作出鉴别。     

PC/ABS共混物的PGC-MS定量分析

采用裂解/气相色谱-质谱联用方法(PGC-MS)对制备的一系列已知配比的PC/ABS共混物进行分析。实验比较了650、750℃裂解温度下共混物的裂解质谱总离子流图,选择PC/ABS共混物的快速鉴定的裂解温度为750℃;通过对已知PC/ABS配比的共混物的特征裂解碎片进行定量分析,发现当共混物中ABS和PC的质量比不大于20∶100时,特征裂解碎片苯乙烯与苯酚的峰面积之比与共混物中ABS/PC的配比呈线性关系,该现象可作为PC/ABS共混物定量分析的依据。     

文物中多糖类胶结材料的热裂解-气相色谱/质谱识别

热裂解-气相色谱/质谱(Py-GC/MS)技术能够实现微量样品中有机组分的准确、快速检测,非常适用于文物中各类天然有机材料的定性分析。该研究以中国古代书画、建筑、器物等文化遗产中常用的淀粉、桃胶,以及西方文化遗产中常用的阿拉伯胶等多糖类胶结材料为研究对象,系统分析并总结各类材料的Py-GC/MS特征裂解组分及辨别方法。研究发现,淀粉、桃胶、阿拉伯胶在色谱保留时间前段的裂解产物基本一致,主要是小分子呋喃、酮类组分;在保留时间中段3类材料的裂解产物主要是呋喃型酮等组分,但不同材料的具体裂解组分差异明显;在保留时间后段,3类材料检出多种单糖衍生物以及单糖低聚体衍生物,其中桃胶与阿拉伯胶裂解组分较为接近,但与淀粉完全不同。因此,可根据不同保留时间段淀粉、桃胶、阿拉伯胶裂解产物的差异实现3类材料的辨别,其中1,6-脱水-β-D-吡喃葡萄糖只在淀粉中检出且色谱峰强度高,可以作为识别淀粉的特征组分;此外,可根据桃胶、阿拉伯胶在保留时间后段的裂解产物主要质谱碎片离子m/z 60、m/z 101的提取离子流图分布特征实现其辨别。基于所建立的Py-GC/MS方法,研究推断故宫旧藏清代剔红云龙纹天球瓶瓶口部位黏结材料含有面粉,旻宁御笔并蒂含芳贴落画心纸所用黏结材料为面粉糨糊。该研究所建立方法及所总结的数据易于推广,适用于我国文物中多糖类材料的准确、快速识别,研究结果能为相关文物材质工艺的研究以及保护修复方案的制定提供科学依据。     

乙二醇醇解松木屑反应特征及机理分析

利用酸化的乙二醇作溶剂对松木屑进行醇解,探讨了温度和时间对醇解转化率的影响。利用热重分析、红外光谱分析、扫描电镜及X射线衍射考察了醇解残渣的性质。分别利用傅里叶变换红外光谱及色质联用分析了正己烷不溶物和可溶物中组分的分布及特征。结果表明,松木屑转化率在90 min、160℃达到最大值95.3%。松木屑中纤维素无定形区的组分和木质素发生了解离,醇解残渣的表面结构被破坏;正己烷不溶物是含有羟基、甲氧基及醚键等含氧官能团的化合物;正己烷可溶物主要由苯二甲酸酯、硬脂酸甲酯、2-甲基己酸丙酯、2-甲基丙酸、聚乙二醇及未反应的乙二醇组成。乙二醇与松木屑解离的羧酸发生酯化反应,对液相产物具有稳定作用,促进了松木屑的醇解反应;醇解过程中乙二醇自缩聚生成聚乙二醇,增大了乙二醇的消耗。     

化妆品痕迹物证差异性的比对分析

本文以口红和指甲油为研究对象,共收集了21个同一品牌不同型号颜色相近的口红样本和30个三种颜色、不同品牌不同型号的指甲油样本。使用显微分光分光度计测定样本的色度数据并结合色度学理论计算色差;使用气质联用法对色差很小样本的总离子流图进行比对分析和结构解析,并进一步对总离子流图差异较小的样本选择邻苯二甲酸酯这类特定杂质结构差异进行比对分析。实验结果表明:210份口红样本的色差数据,色差小于1.5的数据为5份,占总比对样本数的2.38%;147份指甲油样本的色差数据,色差小于1.5的数据为6份,占总比对样本数的4.08%。大部分色差很小的样本之间总离子流图谱有较大差别,少部分色差和总离子流图差异均较小样本的特定杂质邻苯二甲酸酯的结构式和质谱图存在明显差异,从而可将口红、指甲油样本分别加以区分,为口红、指甲油的比对分析提供了新思路和新手段。     

不同涤纶绳索纤维的PY-GC/MS定性分析

利用裂解-气相色谱/质谱联用法对9个不同产地、不同规格的涤纶绳索样品进行鉴别分析.首先通过优化选择,确定试验条件,即裂解温度为550℃、裂解时间为6 s时,柱程序升温条件为50℃(1 min)20℃/min→250℃(10 min).在此条件下可最大限度的显示涤纶裂解产物的特征.9个样品的裂解分析结果显示,涤纶的主要裂解产物有13种,其中特征裂解产物为苯甲酸(相对强度100%)、苯甲酸乙烯酯、联苯、苯等.虽然9个涤纶绳索有相同的裂解特征,但个别裂解产物及各特征裂解产物的相对含量有所不同.这一差异可以作为不同规格、不同产地涤纶绳索分析鉴别的依据.     

沙门氏菌全细胞的热裂解气相色谱-质谱分析

本研究探讨了一种新型的快速检测食源性病原菌的方法。该方法应用热裂解气相色谱-质谱技术(pyrolysis-gas chromatography-mass spectrometry,Py-GC-MS)对食源性致病菌沙门氏菌进行了分析。通过对影响总离子流色谱图条件(热裂解条件、色谱条件、质谱条件)的研究,得到了满意的实验结果。结果表明:沙门氏菌全细胞在裂解温度600℃,时间为10s,离子源温度220℃,电离方式为EI,电离能为60eV的条件下可得到清晰的总离子流色谱图,同时对部分裂解产物的结构进行了鉴定。该方法快速、简便,可为研究快速鉴定致病菌提供新的技术手段。     

反相高效液相色谱分析种子醇溶蛋白表征燕麦种质

〕用反相高效液相色谱技术分析了17个不同倍性水平的燕麦种质收集物的种子醇溶蛋白,发现其色谱组分峰数随燕麦倍性水平的增加而有所增多,且宜所有不同收集物的色谱图型差异显著,并均表现出各自明显的特异性。因此,应用此技术分析燕麦种子醇溶蛋白可以对燕麦种质进行染色体倍性水平鉴定和收集物鉴定。     

基于分布活化能模型法的农林生物质热解动力学对比研究

采用热重质谱（TG-MS）联用技术,考察杏壳、小麦秸秆与杨树木屑等典型农林生物质的热解行为及动力学。结果表明,组分差异使得三种生物质在主要反应区间内（200–450℃）表现出不同的特征。采用等转化率法计算发现,杏壳平均活化能为188.22 kJ/mol,秸秆平均活化能为220.77 kJ/mol,木屑平均活化能为175.87 kJ/mol。利用分布活化能模型（DAEM）法计算生物质中各组分的平均活化能,发现三种生物质中存在平均活化能较高的第四组分（杏壳297.44 kJ/mol、秸秆284.35 kJ/mol和木屑309.96 kJ/mol）,而半纤维素与纤维素呈现“秸秆<杏壳<木屑”规律。各类动力学计算方法能够互为补充,等转化率方法的整体计算结果与单组分分布活化能模型法结果接近,方法更简便,而分布活化能模型法可以求得原料不同组分的动力学参数,弥补等转化率法的不足,综合使用可以形成对热解反应更为全面的认识。     

阴行草中挥发油的分析

阴行草(SiphonostegiachinensisBenth.)系玄参科植物。全草地上部分入药,《中药志》编入刘寄奴条^[1],《中药大辞典》编入钤茵陈条^[2]。其药用功效和可制疗的疾病参见文献^[1.2]。有关阴行草的化学组分,中国医学科学院药物研究所曾指出含挥发油、强心甙等^[3],但具体组分,目前尚未见报导。本文报导了空心柱气相色谱-质谱法对阴行草挥发油的分离和鉴定结果,共鉴定了35个组分,占总油含量(按总离子流图面积归一法人工估算)的92.5％,相对含量在1％以上的16个主要组分全部鉴定。     

Extrusion Pretreatment of Pine Wood Chips

Pretreatment is the first step to open up lignocellulose structure in the conversion of biomass to biofuels. Extrusion can be a viable pretreatment method due to its ability to simultaneously expose biomass to a range of disruptive conditions in a continuous flow process. Extruder screw speed, barrel temperature, and feedstock moisture content are important factors that can influence sugar recovery from biomass. Hence, the current study was undertaken to investigate the effects of these parameters on extrusion pretreatment of pine wood chips. Pine wood chip at 25, 35, and 45?% wb moisture content were pretreated at various barrel temperatures (100, 140, and 180?°C) and screw speeds (100, 150, and 200?rpm) using a screw with compression ratios of 3:1. The pretreated pine wood chips were subjected to standard enzymatic hydrolysis followed by sugar and byproducts quantification. Statistical analyses revealed the existence of significant differences in sugar recovery due to independent variables based on comparing the mean of main effects and interaction effects. Pine wood chips pretreated at a screw speed of 150?rpm and a barrel temperature of 180?°C with a moisture content of 25?% resulted in a maximum cellulose, hemicellulose, and total sugar recoveries of 65.8, 65.6, and 66.1?%, respectively, which was about 6.7, 7.9, and 6.8 fold higher than the control (unpretreated pine chips). Furthermore, potential fermentation inhibitors such as furfural, hydroxyl methyl furfural, and acetic acid were not found in any of the treatment combinations.     

Profiles of extracellular proteins produced byCoriolus versicolor under ligninolytic and nonligninolytic growth conditions

The wood-rotting basidiomyceteCoriolus versicolor has been grown under a variety of conditions ranging from stationary cultures on spruce wood chips or milled-wood lignin, known to be actively ligninolytic, to agitated submerged cultures, with glucose or carboxymethylcellulose as the main carbon source, that had no ligninolytic activity. Extracellular proteins have been recovered from the growth medium by ammonium sulfate precipitation and fractionated into their polypeptide components by a combination of ion exchange, affinity column chromatography, and polyacrylamide gel electrophoresis, thus providing a “fingerprint” technique for different growth conditions. Characterization of some of the polypeptide components on the PAGE plates can be made by the use of selected staining techniques for proteins, glycoproteins, peroxidase activity, and heme-containing polypeptides. Variations in the “fingerprints” from different cultures can be demonstrated, in addition to showing the development of the extracellular protein population in an actively ligninolytic culture during the change from primary to secondary growth phases. The effect of some of the extracellular enzymes on polymeric lignin has been demonstrated. A crude protein extract isolated from rotting wood chips was incubated with milled-wood lignin extracted from spruce sapwood. Analysis of the lignin after 48 h incubation by UV and NMR spectroscopy showed there to be an increase in aromatic hydroxyl groups with a decrease in aliphatic hydroxyl groups in comparison with sound milled-wood lignin. There was also a small reduction in the mean molecular weight of the lignin, analyzed by HPLC size-exclusion chromatography. By contrast, lignin that had been incubated with purified laccase A showed a considerable increase in the mean molecular weight, almost doubling over a 48-h period of incubation.     

Steam pretreatment of Salix with and without SO2 impregnation for production of bioethanol

In the wood-to-ethanol process, pretreatment of the material is necessary prior to enzymatic hydrolysis to obtain high overall yields of sugar and ethanol. Steam pretreatment of fast-growing Salix either with or without SO₂ impregnation has been investigated by varying different parameters. Overall glucose yields of above 90% and overall xylose yields higher than 80% were obtained both with and without impregnation. However, the most favorable pretreatment conditions for the separate yields of glucose and xylose differed to a lower degree using SO₂-impregnated wood chips, resulting in higher total sugar yield than that obtained with non-impregnated wood chips.     

固相萃取-高效液相色谱-电喷雾串联质谱法分析芍药和酒芍药的水溶性化学成分

利用固相萃取-高效液相色谱-电喷雾串联质谱法(SPE-HPLC-DAD-ESI-MS2)分析了芍药(Paeonia lactiflora Pall.)及其炮制品酒芍药(Paeonia lactiflora Pall.preparated with wine)水煎液中化学成分的种类和结构,并对其主要有效成分芍药苷进行了定量测定.用此方法得到了芍药和酒芍药水煎液的紫外色谱(UV)图、总离子流色谱(TIC)图和萃取离子色谱(EIC)图,以及相应色谱峰的紫外光谱图和EIC/MS2的质谱图.对其进行解析,发现芍药和酒芍药水煎液中所含化学成分基本一致,但酒芍药水煎液中除主要活性成分芍药苷含量基本未变外,其它酚酸性化学成分含量相对于芍药水煎液均有不同程度的下降.同时鉴别出芍药和酒芍药水煎液中共同含有的16种成分,它们分别是:蔗糖、(+)-儿茶素、Mudanpioside E、芍药新苷、芍药内酯苷、氧化芍药苷、芍药苷、羟基芍药苷、没食子酰芍药苷*、牡丹皮苷Ⅰ、苯甲酰芍药苷、三没食子酰葡萄糖、四没食子酰葡萄糖、五没食子酰葡萄糖.以上分析说明,酒炙可保留芍药的药效,同时"缓和其酸寒伐肝之性".     

Application of liquid chromatography coupled with electrospray ionization time-of-flight mass spectrometry for screening and quantitative analysis of C21 steroids in the roots and rhizomes of Cynanchum paniculatum

A liquid chromatography-mass spectrometry method is presented for the quantification of C21 steroids in the roots and rhizomes of Cynanchum paniculatum. Eight C21 steroids, including five steroidal aglycones and three steroidal glycosides, were simultaneously analyzed by liquid chromatography coupled with electrospray ionization time-of-flight mass spectrometry. The extracted ion current chromatograms were extracted from the total ion current chromatogram using characteristic ions produced by target compounds for peak determination. Chromatographic separation was achieved on a C18 reversed-phase column within 60 min, using an acetonitrile/water gradient. For comparision, six C. paniculatum samples from different locations were investigated by the established method, and the results indicated that the different geographical origin significantly influenced the C21 steroid composition. The method was observed to have the necessary sensitivity, selectivity, precision, and accuracy, and to be suitable for quality control of herbal medicines and their preparations.     

基于选择离子集成谱的中药质量评价新方法

采用液相色谱-质谱(LC-MS)联用技术建立了不同产地的双丹方(丹参和丹皮)煎剂的指纹图谱, 并提出一种将二维的LC-MS数据转化为一维的选择离子集成谱(ISIC)的方法. 通过主成分分析考察了ISIC与总离子流色谱图(TIC)和保留时间校正后的TIC对不同产地药材的区分能力. 结果表明, ISIC能全面反映不同产地的丹参和丹皮成分间的差异; 而TIC由于色谱峰重叠严重, 对不同产地的药材无区分能力, 保留时间校正后的TIC仅能反映不同产地丹参成分间的差异. 该方法运算速度快, 适于大批量样本分析, 生成的ISIC信息量大, 且不需校正保留时间, 可直接用于后续的统计分析.     

Influence of torrefaction on the devolatilization and oxidation kinetics of wood

Devolatilization and oxidation kinetics of torrefied wood have been studied by evaluating thermogravimetric curves measured in nitrogen and air at various heating rates. Samples consist of Norway spruce wood chips torrefied at several process temperatures and residence times. Data about untreated wood have also been obtained for comparison. Measured curves are well predicted by means of a five-reaction mechanism, consisting of three devolatilization reactions for the pseudo-components hemicellulose, cellulose and lignin and, in air, of two additional reactions for char devolatilization and combustion. The torrefaction pre-treatment only requires model modifications in the amounts of volatiles generated from the decomposition of pseudo-components, indicating that only their relative percentages and not their reactivities are modified. On the other hand, a slightly different thermal stability is found for the char generated from torrefied wood, which results in higher activation energy and lower reaction order for the oxidation step. Hence torrefaction conditions can affect the subsequent conversion characteristics of the char product.     

Distinction between melanins derived from different precursors using pyrolysis/gas chromatography/mass spectrometry and the NIST mass spectral search algorithm

A method was required to objectively determine whether various melanins were synthesised from different precursors, and whether synthesis from the same precursor was reproducible. Melanins have a complex, heterogeneous, polymeric structure, making them difficult to characterise and compare. Pyrolysis chromatography may be useful for such large molecules that are not amenable to analysis by other methods, but the resulting chromatograms are usually complex and difficult to compare. Techniques used to objectively differentiate between such chromatograms often employ statistical methods that are difficult to use and interpret without specialised knowledge. Melanins were analysed by pyrolysis/gas chromatography/mass spectrometry (PY/GC/MS). Software was developed to automate the conversion of the resulting total ion current (TIC) chromatograms to pseudo-mass spectra (PMS), consisting of a row vector of chromatographic peak areas (analogous to ion abundances) ordered along a retention time axis (analogous to m/z ratio). The National Institute of Standards and Technology (NIST, USA) mass spectral search program, which is used widely as an objective measure of the degree of similarity between mass spectra, was then used to generate match factors for comparisons of the generated PMS. Match factors between melanins synthesised from the same precursors were not significantly different, while match factors between melanins synthesised from different precursors were significantly smaller. The reproducibility of the pyrolysis technique was reasonable, with the majority of relative standard deviation (RSD) values of match factors from melanins synthesised from the same precursor, being below 10% (n=5 for each melanin type). While the method does not allow the unequivocal identification of individual melanin types in isolation, it can be used to compare melanins from different sources and objectively estimate the degree of similarity between them on the basis of significant differences between their pyrograms.     

广藿香化学成分和指纹图谱研究

采用气相色谱-质谱联用技术(GC-MS),对石牌、高要、湛江3个栽培品种的广藿香挥发性成分进行了研究,分别鉴定了其化学组成,并测定了其相对含量。采用色谱指纹图谱分区法对3个栽培品种广藿香的质量进行分析和比较,把广藿香总离子流色谱图分为4个区,并用相对保留值α和相对峰面积Sr进行分析比较。结果表明,此法简单、快速,为有效地鉴别不同栽培品种的广藿香以及建立其色谱指纹图谱提供了一种新的方法。本研究还讨论了广藿香酮结构的确定。