信阳毛尖茶叶挥发性成分GC/MS分析

本文采用SDE蒸馏萃取方法提取信阳毛尖茶叶的挥发性成分,用气质联用仪及SE-54和强极性BPX70毛细色谱管柱进行分离分析比较,中等极性SE-54毛细色谱管柱分离效果较好,春茶挥发性成分中共分离并鉴定出47个峰;夏茶挥发性成分中共分离并鉴定出64个峰。对比夏茶与春茶在香气成分上的差异,综合评价春茶的香气品质优于夏茶。     

康酿克油中挥发性成分的气相色谱/飞行时间质谱法分析

采用气相色谱-飞行时间质谱（GC-TOF/MS）联用技术测定白康酿克油和绿康酿克油的挥发性成分,并用峰面积归一化法计算了各成分的相对含量。通过质谱库检索,结合保留指数比对,从白康酿克油和绿康酿克油中分别鉴定出82和61个挥发性成分,分别占总峰面积的98.63％和97.62％。白康酿克油的主要成分为月桂酸乙酯（23.50％）、癸酸乙酯（18.19％）、癸酸（12.35％）、辛酸乙酯（7.38％）、棕榈酸乙酯（7.28％）、肉豆蔻酸乙酯（6.68％）、癸酸异戊酯(6.56％)、辛酸己酯（3.06％）、辛酸异戊酯（2.48％)、苯甲酸（2.04％）、2-酮代棕榈酸甲酯（1.81％）、月桂酸异戊酯（1.02％)等。绿康酿克油的主要成分为月桂酸乙酯（23.99％）、癸酸乙酯（18.28％）、癸酸（12.45％）、辛酸乙酯（7.28％）、癸酸异戊酯（6.36％）、肉豆蔻酸乙酯（5.31％）、棕榈酸乙酯（5.21％）、辛酸异戊酯（2.80％）、辛酸（2.45％）、辛酸己酯（2.06％）、月桂酸异戊酯（1.12％）等。通过保留指数法来鉴别同分异构体及同系物,提高了康酿克油中挥发性成分定性的准确性。该研究为康酿克油制定科学的质量标准以及合理开发利用提供初步实验依据。     

牛大力藤叶脂溶性成分的GC-MS分析

采用气相色谱一质谱联用技术(GC-MS)对牛大力藤叶片脂溶性成分进行分析测定,并结合计算机检索技术对其成分进行结构鉴定,应用色谱峰面积归一化法计算各成分的相对百分含量.结果显示,共鉴定了41个化学成分(除豆甾醇外,其余40个化学成分在该植物中属首次报道),其相对含量为81.22%.其中含量较高的成分依次为维生素E(11.52%)、亚麻酸乙酯(10.26%)、γ-谷甾醇(8.53%)、棕榈酸乙酯(8.23%)、叶绿醇(7.00%)、亚麻酸甲酯(5.04%)、亚油酸乙酯(4.13%)、亚油酸(4.09%)和植二烯(3.89%).     

普洱茶粉挥发性成分全二维气相色谱/飞行时间质谱研究

以非极性柱Rxi-5Sil MS为第一维柱,中等极性柱Rtx-200为第二维柱,对普洱茶粉的挥发性成分进行全二维气相色谱-飞行时间质谱分析。结合飞行时间质谱普检索图库与全二维特有结构信息谱图,鉴定出相似度大于800、含量≥0.1%的物质90种,占总峰面积的66.306%。研究结果表明,全二维气相色谱-飞行时间质谱联用系统的高分离度、高峰容量和高灵敏度,以及全二维分离特有的结构谱图特征,非常适合于普洱茶粉中复杂挥发性组分的研究。     

澳洲坚果焙烤过程中挥发性成分的特征分析

利用顶空-固相微萃取-气相色谱质谱联用技术对焙烤澳洲坚果的挥发性成分进行定性定量分析;比较了原料澳洲坚果和130℃焙烤10、15、25、35、40、50和60 min,以及市售商品澳洲坚果的挥发性成分的含量差异。分离鉴定得到130℃焙烤澳洲坚果中的23种典型的挥发性物质,包括9种醛类、9种吡嗪类、2种呋喃类和3种其他物质。原料澳洲坚果中的挥发性成分比较少,市售澳洲坚果中的调味料香气含量较高,坚果香气物质较少。随着焙烤时间的延长,焙烤香气逐渐增加,其中吡嗪类和呋喃类的含量在130℃焙烤处理组之间均差异显著。2-甲基吡嗪和3-乙基-2,5-二甲基吡嗪以及2-乙酰基吡咯也能作为进一步指示10~60 min不同焙烤时间之间焙烤程度差异显著的标志物质,用以规范澳洲坚果焙烤工艺和指导焙烤产品品质分级。     

超临界法萃取的黑胡椒油树脂成分分析

在超临界CO2萃取压力为30 Mpa、萃取时间为3 h、萃取温度为50℃的静态条件下,分别萃取未做任何处理、无水乙醇处理、乙酸乙酯处理的黑胡椒原料中的油树脂,并利用气相色谱-质谱联用(GC-MS)对萃取得到的黑胡椒油树脂进行成分分析,同时利用保留指数和MS对物质进行定性分析。结果显示,在超临界萃取条件下,未做任何前处理的黑胡椒油树脂的香气成分有22种,采用无水乙醇进行前处理的黑胡椒油树脂的香气成分有17种,采用乙酸乙酯进行前处理的黑胡椒油树脂的香气成分有41种。     

复合酶提取人参的高效液相色谱-电喷雾质谱研究

采用高效液相色谱法和电喷雾质谱联用技术并结合紫外光谱技术对复合酶提取的人参化学成分进行了分析,结果表明复合酶可提高人参的提取效率,提取物中人参皂苷Re、Rg1、Rg2、Rb1、Rc、Rb2、Rd、Rk3、Rh4的含量明显增多,并得到了常规提取方法中不能得到的Rk1、Rg5、20(S)-Rg3和20(R)-Rg3。复合酶法提取天然药物并结合高效液相色谱和电喷雾质谱联用技术进行即时分析具有高效,灵敏和直观的特点,以实现对人参中微量成分的检测,并可指导其他天然药物的研究。     

金钟藤叶石油醚萃取部分脂溶性成分分析

采用气相色谱-质谱(GC-MS)技术对金钟藤叶石油醚萃取部分脂溶性成分进行分析。结果表明：从金钟藤叶石油醚萃取部分中共鉴定出54种化合物,占色谱峰的76.23%。金钟藤叶石油醚萃取部分脂溶性成分主要为醇类、酯类、萜类、烃类、酸类等,其中含量较高的成分依次为叶绿醇(11.90%)、穿贝海绵甾醇(5.99%)、十烷烃(4.58%)、棕榈酸乙酯(4.14%)、蒲公英醇(3.75%)、三十烷(3.05%)、异丁基邻苯二甲酸(2.84%)、豆甾醇(2.11%)、十八烷二醇(2.11%)、正癸酸(2.07%)、生育酚(2.00%),说明金钟藤叶石油醚萃取部分脂溶性成分中确实含有具有化感作用的化学物质。此研究为金钟藤的化感成分研究提供依据。     

黄牛木叶脂溶性成分研究

首次采用气相色谱-质谱联用技术GC-MS对黄牛木[Cratoxylum cochinchinense (Lour.)Bl.]叶的脂溶性成分进行分析,从中鉴定出25个化合物,占其总量的76.32%。在已鉴定的25个化学成分中,含量较高的成分依次为α-D-乙基葡萄糖苷(18.93%)、2-羟基-2-环戊烯-1-酮(16.77%)、棕榈酸(9.27%)、棕榈酸乙酯(5.18%)、儿茶酚(4.27%)、软木三萜酮(3.11%)等。     

烘焙速度对兴隆咖啡豆挥发性成分的影响

以海南兴隆地区咖啡豆（Coffea robusta）为研究对象,研究不同烘焙方式（即快速烘焙、中速烘焙以及慢速烘焙）对咖啡豆理化性质和挥发性成分的影响,采用顶空固相微萃取-气相色谱-质谱联用技术（headspace solid-phase microextraction-gas chromatograph-mass spectrometry,HS-SPME-GC-MS）鉴定3种烘焙速度下产生的挥发性成分,再以电子鼻技术和主成分分析（principal component analysis,PCA）法进一步分析不同烘焙豆样品整体风味的差异。结果表明,3种烘焙方式下共鉴定出92种挥发性成分,其中快速、中速和慢速烘焙豆中分别鉴定出82、72、76种;烘焙豆样品间挥发性成分含量相差较大,在中速烘焙豆中检测出最高的挥发性成分总含量（1080.51 μg/g）;电子鼻检测发现不同烘焙方式咖啡豆挥发性成分存在差异,PCA结果显示三者差异明显,其中中速和慢速烘焙样品的挥发性成分有部分重叠现象,二者与快速烘焙样品差别较大。本研究可为咖啡烘焙工艺改进及品质提升提供参考。     

超高效液相色谱-串联高分辨质谱法分析植物油料及油脂中鞘脂组成

鞘脂及其代谢产物具有较强的生物活性,参与了细胞增殖、分化、免疫、凋亡及衰老等重要的生理活动,对人体的健康具有十分重要的影响.本研究采用超高效液相色谱串联高分辨质谱法并结合LipidSearch数据库软件测定和分析了菜籽油、大豆油和花生油三种常见植物油和对应的油料作物的鞘脂组成特性,采用一级质谱母离子相对分子质量以及二级...     

基于液相色谱-串联质谱法分析不同植物油经加热处理前后氧化脂肪酸的变化

植物油中的氧化脂肪酸主要是亚油酸(linoleic acid, LA)和亚麻酸(linolenic acid, ALA)等多不饱和脂肪酸在酶、光照、加热等条件下产生的过氧化羟基脂肪酸(hydroperoxyl fatty acid)、羟基脂肪酸(hydroxy fatty acids)和环氧基脂肪酸(epoxy fatty acid)等。这些氧化脂肪酸的变化在一定程度上反映了油脂本身的氧化稳定性和氧化初期的变化,可作为植物油氧化初级阶段标志物。本研究基于高效液相色谱-三重四极杆质谱(high performance liquid chromatography triple quadrupole mass spectrometry,HPLC-Qq Q-MS/MS)联用技术,对室温和180℃加热处理30min后的菜籽油、葵花油、紫苏油、亚麻籽油中氧化脂肪酸进行了定性和定量分析。结果表明,相比于室温,经180℃加热处理30min,4种植物油中的LA、ALA等多不饱和脂肪酸含量下降;大部分LA、ALA类氧化脂肪酸的含量明显提高。经主成分分析(Principal component analysis, PCA),不同种类和处理下的植物油样本聚类明显,差异显著;经偏最小二乘法判别分析(Partial least squares discriminant analysis,PLS-DA),发现了植物油加热氧化初期的13-HODE、13-oxo-ODE、12,13-Ep OME、9,10-Ep ODE、12,13-Ep ODE、15,16-Ep ODE六种潜在的标志物,本研究对植物油氧化初期的评价以及植物油氧化初级阶段机制的深入研究具有一定的指导意义。     

Composition of essential oil, concrete, absolute and SPME analysis of Tagetes patula capitula

The chemical compositions of essential oil, concrete, absolute from the capitula of Tagetes patula (family Asteraceae) were analysed by GC-FID and GC/MS. The major compounds identified were (Z)-β-ocimene, (E)-β-ocimene, terpinolene, (Z)-ocimenone, (E)-ocimenone and δ-elemene. In addition, the volatiles of live and plucked capitula (flowers) were analysed by SPME technique using PDMS/DVB/CAR fiber. The SPME-GC-FID analyses of live capitula showed that the volatiles were rich in monoterpenoids in comparison to the plucked capitula. On the other hand, the plucked capitula recorded with significant increase in sesquiterpenoids in comparison to the living capitula.     

Mathematical modeling for extraction of essential oil from Baccharis spp. by steam distillation

Baccharis (Compositae-Asteraceae) is a large genus of plants distributed from the USA to Argentina, of which 90% are located in South America. In recent decades, species of the genus have been studied, due to their importance as sources of novel active components with possible applications in the pharmaceutical and chemical industries. This work studied three species of Baccharis: Baccharis uncinella DC, Baccharis anomala DC and Baccharis dentata (Vell) G.M. Barroso collected in São Francisco de Paula in southern Brazil. The aim of this work is the evaluation of the aromatic potential of the essential oil obtained by steam distillation method and the simulation of the extraction data by means of a mathematical model. A mathematical model based on mass transfer fundamentals is developed and applied to correlate the experimental data. This model is based on the existence of the broken and intact cells, in which the oil located in the broken cells is rapidly extracted and the oil from intact cells diffuses slowly to the surface of the vegetal material. The analysis of the essential oil was carried through by GC-MS and the major compounds identified to both processes were α-pinene, β-pinene, and spathulenol (B. uncinella), spathulenol, β-caryophyllene, and β-selinene (B. anomala), and germacrene-D, caryophyllene oxide, and spathulenol (B. dentata).     

超高效液相色谱-串联四级杆质谱联用法测定甘蔗中噻虫胺 的残留

本研究建立了超高效液相色谱串联质谱（UPLC-MS/MS）法检测甘蔗中噻虫胺残留量的方法。甘蔗植株、茎 秆及嫩稍样品经乙腈-水（V∶V=2∶1）提取,Envi-Carb 复合 PSA 固相萃取小柱净化,ACQUITY UPLC BEH C18 色谱 柱分离,电喷雾正离子源（ESI+ ）多反应监测（MRM）模式检测,外标法定量。结果表明：采用 Envi-Carb 固相萃取 小柱,以乙腈为淋洗液,在小柱中添加 PSA 净化效果最好。在甘蔗植株、茎秆及嫩稍中分别添加 0.04、0.4、1 mg/kg 噻虫胺,平均回收率为 81.4%~109.1%,相对标准偏差（RSD）为 0.9%~10.9%。该方法的最小检出量为 0.4 ng,在甘蔗 中的最低检出浓度（LOD）为 0.04 mg/kg,能满足农药残留检测的要求。     

A Collaborative Evaluation of LC-MS/MS Based Methods for BMAA Analysis: Soluble Bound BMAA Found to Be an Important Fraction

Exposure to β-N-methylamino-l-alanine (BMAA) might be linked to the incidence of amyotrophic lateral sclerosis, Alzheimer’s disease and Parkinson’s disease. Analytical chemistry plays a crucial role in determining human BMAA exposure and the associated health risk, but the performance of various analytical methods currently employed is rarely compared. A CYANOCOST initiated workshop was organized aimed at training scientists in BMAA analysis, creating mutual understanding and paving the way towards interlaboratory comparison exercises. During this workshop, we tested different methods (extraction followed by derivatization and liquid chromatography coupled to tandem mass spectrometry (LC-MS/MS) analysis, or directly followed by LC-MS/MS analysis) for trueness and intermediate precision. We adapted three workup methods for the underivatized analysis of animal, brain and cyanobacterial samples. Based on recovery of the internal standard D₃BMAA, the underivatized methods were accurate (mean recovery 80%) and precise (mean relative standard deviation 10%), except for the cyanobacterium Leptolyngbya. However, total BMAA concentrations in the positive controls (cycad seeds) showed higher variation (relative standard deviation 21%–32%), implying that D₃BMAA was not a good indicator for the release of BMAA from bound forms. Significant losses occurred during workup for the derivatized method, resulting in low recovery (<10%). Most BMAA was found in a trichloroacetic acid soluble, bound form and we recommend including this fraction during analysis.     

Comparison of the volatile profiles of the crumb of gluten-free breads by DHE-GC/MS

The aroma of gluten-free bread has been considered of lower quality than that of the common wheat bread. With the aim of improving the aroma of gluten-free bread, the volatile profiles of the crumb of gluten-free breads made from rice, teff, buckwheat, amaranth and quinoa flours as well as corn starch, respectively, were evaluated. Wheat bread was used as a reference and dynamic headspace extraction together with GC/MS was employed. It was found that the whole grain breads, made with teff, quinoa and amaranth flours, presented a stronger aroma with higher number of important aroma contributors. Rice bread was characterised by the highest levels in nonanal and 2,4-decadienal and corn starch bread by 2,3-pentanedione and 2-furaldehyde. Teff presented the highest abundance of ethyl hexanoate and ethyl nonanoate, but also of alcohols and aldehydes from lipid oxidation. Quinoa and amaranth were classified by the highest content in Strecker and Ehrlich aldehydes as well as 1-propanol, 2-methyl-1-propanol, 3-methyl-1-butanol or 3-hydroxy-2-butanone from fermentation. Corn starch bread was the closest to wheat bread in the PCA due to the highest content mainly in 2,3-butanedione and furfural as well as the lowest contents in 1-propanol, 1-hexanol and pentanal.