Fingerprint developing of coffee flavor by gas chromatography-mass spectrometry and combined chemometrics methods

In this paper, chromatographic fingerprint was firstly used for quality control of tobacco flavors. Based on gas chromatography-mass spectrometry (GC-MS) and combined chemometrics methods, a simple, reliable and reproducible method for developing chromatographic fingerprint of coffee flavor, one of tobacco flavors, was described. Six coffee flavor samples obtained from different locations were used to establish the fingerprint. The qualitative and quantitative analysis of coffee flavor sample from Shenzhen was completed with the help of subwindow factor analysis (SFA). Fifty-two components of 68 separated constituents in coffee flavor sample from Shenzhen, accounting for 88.42% of the total content, were identified and quantified. Then, spectral correlative chromatography (SCC) was used to extract the common peaks from other five studied coffee flavor samples. Thirty-eight components were found to exist in all six samples. Finally, the method validation of fingerprint analysis was performed based on the relative retention time and the relative peak area of common peaks, sample stability and similarity analysis. The similarities of six coffee flavor samples were more than 0.9104 and showed that samples from different locations were consistent to some extent. The developed chromatographic fingerprint was successfully used to differentiate coffee flavor from coco flavor and some little difference sample prepared with coffee flavor and coco flavor by both similarity comparison and principal component projection analysis. The developed method can be used for quality control of coffee flavor.     

Comparison of the volatile constituents of Artemisia capillaris from different locations by gas chromatography-mass spectrometry and projection method

The volatile chemical constituents of Artemisia capillaries (an important traditional Chinese medicine) were determined by gas chromatography-mass spectrometry (GC-MS) and sub-window factor analysis (SFA). Seventy-five components were separated and 43 of them were qualitatively and quantitatively determined, which represented about 89.03% of the total content. This profile was then used to identify and assess the consistency of the herb by using an orthogonal projection method. Four different sources of A. capillaries were analyzed and compared with each other. Among the components determined, there were 51 components coexisting in all samples although the relative peak areas of a few showed variations. It is the first time to apply orthogonal projection method to the comparison of different samples, and it reduces the burden of qualitative analysis as well as the subjectivity. The results showed a fair consistency in their GC-MS fingerprint. A. capillaris was distinguished from Artemisia sacrorum L., a possible substitute in traditional Chinese medicine by comparing the fingerprints with each other.     

Development of a Chromatographic Fingerprint of Tobacco Flavor by Use of GC and GC-MS

A new chromatographic fingerprinting method has been established for quality control of tobacco flavor. Three different extraction techniques, simultaneous distillation extraction (SDE), liquid–liquid extraction, and solid-phase microextraction were evaluated for isolation of the components of interest. After comparison of their performance, a combination of SDE and GC-MS was used for simple, reliable, and reproducible development of a chromatographic fingerprint of tobacco flavor. Twelve samples of the flavor from different batches were used to establish the fingerprint. Thirty-nine volatile components of the tobacco flavor samples, accounting for 86.54% of the total content, were identified and quantified. The 12 samples had 28 peaks in common. The method of fingerprint analysis was then validated on the basis of the relative retention times and relative peak areas of the common peaks, sample stability, and similarity analysis. The similarities of the 12 samples of tobacco flavor were >0.80, showing that samples from different batches were, to some extent, consistent. The chromatographic fingerprint developed was successfully used to differentiate tobacco flavor samples from tobacco extract prepared from tobacco leaf, both by similarity comparison and by principal-components projection analysis. The method can be used for quality control of tobacco flavor.     

联用色谱数据的局部分辨

提出了一种对二维数据严重重叠峰中待测组份进行分辨的新方法：子窗口分析法（ｓｕｂｗｉｎｄｏｗ ａｎａｌｙｓｉｓ，ＳＡ）。该方法充分利用重叠区信息，成功地解析出严重重叠峰中待测组份的光谱，进而利用正交投影求得待测组份色谱曲线．这种对二维数据进行局部分辨的方法，降低了对色谱分离条件的要求，可直接应用于未知组份的定性定量分析。     

菌陈挥发油GC-MS指纹图谱分析

建立了菌陈挥发油GC-MS指纹图谱，将正交投影算法用于不同样本中共有峰的提取，提高了共有峰的识别能力，降低了由于保留时间的漂移、质谱检索匹配度不高以及色谱峰重叠而引起的共有峰识别的难度．采用共有峰率、变异率及相似度等几个指标对4个不同产地的菌陈挥发油成分进行了评价，从共性、差异和整体性等多个方面全面表征菌陈挥发油的化学模式特征．结果表明，不同产地的菌陈挥发油成分大致相同，该指纹图谱可用于菌陈中挥发油成分的质量控制．     

茵陈挥发油GC-MS指纹图谱分析

建立了茵陈挥发油GC-MS指纹图谱,将正交投影算法用于不同样本中共有峰的提取,提高了共有峰的识别能力,降低了由于保留时间的漂移、质谱检索匹配度不高以及色谱峰重叠而引起的共有峰识别的难度.采用共有峰率、变异率及相似度等几个指标对4个不同产地的茵陈挥发油成分进行了评价,从共性、差异和整体性等多个方面全面表征茵陈挥发油的化学模式特征.结果表明,不同产地的茵陈挥发油成分大致相同,该指纹图谱可用于茵陈中挥发油成分的质量控制.     

Liquid exclusion adsorption chromatography, a new technique for isocratic separation of nonionic surfactants. III. Two-dimensional separation of fatty alcohol ethoxylates

In this paper, a novel procedure for qualitative and quantitative analysis of the two-dimensional data obtained from GC-MS is investigated to determine chemical components of essential oils in Cortex Cinnamomi from four different producing areas. A new method named iterative optimization procedure (IOP) specially used to resolve embedded peaks is also developed. With the help of IOP and other chemometric techniques, such as heuristic evolving latent projections, evolving factor analysis, sub-window factor analysis and orthogonal projection resolution, and etc., the detection of the purity of chromatographic peaks can be first addressed, and then the overlapping peaks are resolved into the pure chromatogram and mass spectrum of each component. The similarity searches in the MS database are finally conducted to qualitatively determine the chemical components. The results obtained showed that the accuracy of qualitative and quantitative analysis could be greatly enhanced by chemometric resolution methods. The chemometric resolution techniques upon the two-dimensional data can be quite promising tools for the analysis of the complex samples like traditional Chinese medicine.     

交互移动窗口因子分析法(AMWFA)用于二维数据重叠色谱峰的比较分析

采用交互移动窗口因子分析法(AMWFA), 通过挖掘两个体系中的选择性信息, 获得了不同样本间的共有组分数, 还同时得到了各物质对应的光谱或质谱信息. 详细阐述了本法的原理和计算方法, 并用一个模拟的GC-MS 数据对方法进行了验证.     

气相色谱-质谱联用结合化学计量学方法分析光照对鱼腥草挥发性成分的影响

采用色谱-质谱联用技术结合化学计量学方法对不同光照生长条件的鱼腥草挥发性成分进行分析。水蒸气蒸馏法提取鱼腥草挥发油,气相色谱-质谱进行分析。色谱指纹图谱结合主成分分析与相似度评价以探究不同光照挥发油成分的异同。直观推导式演进特征投影法(Heuristic evolving latent projections,HELP)分辨重叠色谱峰,NIST标准质谱库结合相关文献进行定性,峰面积归一化法定量,t-检验比较不同光照组成分含量间是否有显著性差异。3种光照下的鱼腥草挥发油指纹图谱存在一定的共性和差异,共鉴定出33种化合物,共有化合物26种。随着光照强度的减少,单萜类化合物含量减少,非萜类含量增多,倍半萜类变化不大。癸酰乙醛和甲基正壬酮在全光照组的含量明显低于遮光组的含量。研究结果表明,适度的遮光有利于鱼腥草挥发性有效成分含量的提高,鱼腥草药材挥发性成分种类及含量与生长条件密切相关。     

Efficient recovery of electrophoretic profiles of nucleoside metabolites from urine samples by multivariate curve resolution

Chemometric techniques usually employed in purity assessment and resolution of multicomponent peaks have been applied to analytical data from complex biological samples obtained with CE‐DAD. In the assessment of the purity of the electrophoretic peaks, the orthogonal projection approach, the orthogonal projection approach with Durbin–Watson criterion, and the simple‐to‐use interactive self‐modeling mixture analysis method have been employed. Multivariate curve resolution with alternating least squares has been successfully implemented to resolve co‐migrating peaks of metabolites in CE‐DAD and to recover qualitative and quantitative information about co‐migrating components of urine extract. The main challenge consisted of developing high‐quality multivariate curve resolution with alternating least squares models of multicomponent peaks acquired during the CE analysis of nucleoside patterns in 18 urine samples. The recovered ultraviolet visible (UV–Vis) spectra have been employed to identify additional nucleosides, such as 1‐methylinosine, 2‐methylguanosine, and 1‐methylguanosine, whose presence in the metabolic profile produced by the applied CE‐DAD method has not yet been recognized. Concentration profiles of these compounds can be used in metabonomic studies.     

GC-MS与交互移动窗口因子分析法(AMWFA)用于3种陈皮挥发油成分的比较分析

将GC-MS法与新近提出的用于二维数据比较和解析的交互移动窗口因子分析法(AMWFA)结合, 对3种不同原植物来源的陈皮挥发油成分的共性和差异性进行分析, 并对重叠峰进行解析, 总共分辨出138个峰, 定性出78个峰, 其中共有组分44个.     

Resolving batch chromatographic overlapping peaks of flavoring essence using stepwise key spectrum selection

Stepwise key spectrum selection (SKSS) was introduced to resolve batch overlapping peaks from gas chromatography-mass spectrometry (GC-MS) analysis of ten batch tobacco flavoring samples in different storage times. Resolution was implemented on a software platform that embedded the SKSS method. The data from GC-MS analysis of the samples were saved and prepared in ASCII files and then were inputted into the software platform for visual inspections. The data segment with overlapping peaks was precut for subsequent analysis. Spectral background in the data was removed using a linear fitting of the baseline. Four components in the overlapping peaks were automatically detected by the SKSS method. The resolution of the concentration profiles and spectra of the four components was conducted by setting only one parameter, the negative area ratio, as 0.01. The fixed size moving window evolving factor analysis and evolving factor analysis were applied to validate the resolved concentration profiles. The resolved mass spectra were validated by the searched standard through library search at the pure component regions revealed by the resolved concentration profiles. The results showed that the SKSS method could be a simple but powerful tool in resolving batch chromatographic overlapping peaks.     

基于组效关系的姜黄挥发油抗肿瘤活性成分辨识研究

基于GC-MS分析,建立了姜黄挥发油的化学成分与其抑制人宫颈癌Hela细胞作用的组效关系模型,寻找与药效显著相关的活性成分。采用水蒸汽蒸馏法提取得到31批姜黄挥发油,提取率在1.63%～4.52%之间;采用GC-MS联用仪建立了31批姜黄挥发油的指纹图谱,确定了20个特征峰,以特征峰的相对峰面积(各峰面积与内标正十三烷的峰面积之比)来表征其相对含量;MTT法测定姜黄挥发油抑制人宫颈癌Hela细胞活性,以抑制率为评价指标;利用Simca-p11.5软件的正交投影偏最小二乘法(Orthogonal Partial leastsquares,OPLS)和SPSS软件的双变量相关(bivariate)分析,研究特征峰与药效的相关性,根据S-载荷图、变异权重参数值(Variable importance in projection,VIP)和皮尔逊(Pearson)相关系数来辨识显著活性成分。结果表明,11,15,7,19,3,6,12,14,9号等9个特征峰与姜黄挥发油抑制Hela细胞活性显著相关,除19号峰尚未定性外,11,15,7,3,6,12,14和9号峰对应的成分分别为芳姜黄酮、β-姜黄酮、姜烯、β-榄香烯、α-姜黄烯、α-姜黄酮、吉马酮和β-倍半水芹烯。     

Comparative analysis of volatile components from Clematis species growing in China

The volatile components between stems and roots and also among five Clematis species from China were studied and analyzed by gas chromatography-mass spectrometry (GC-MS) combined with alternative moving window factor analysis (AMWFA), a new chemometric resolution method. Identification of the compounds was also assisted by comparison of temperature-programmed retention indices (PTRIs) on HP-5MS with authentic samples included in our own laboratory database under construction. A total of 153 different compounds accounting for 86.6-96.5% were identified and significant qualitative and quantitative differences were observed among the samples. The major volatile components in different essential oils from Clematis species were n-hexadecanoic acid and (Z,Z)-9,12-octadecadienoic acid. Our work further demonstrated chemometric resolution techniques upon the two-dimensional data and PTRIs can provide a complementary and convenient method for fast and accurate analysis of complex essential oils.     

Comparison of different extraction methods: steam distillation, simultaneous distillation and extraction and headspace co-distillation, used for the analysis of the volatile components in aged flue-cured tobacco leaves

Steam distillation (SD), simultaneous distillation and extraction (SDE) and headspace co-distillation (HCD) were compared here for their effectiveness in the extraction of volatile compounds from tobacco. The different grades of aged flue-cured tobacco leaves extracted by the three methods respectively were analyzed using GC-MS. Mass spectra or authentic compounds were used to identify around 408 components in various volatile fractions. On the one hand, the qualitative comparison showed that more compounds were detected in HCD extract (391 components) than in SDE extract (377 components), and the approximately quantitative analysis showed that the total amount of volatile components in SDE extract (445.48 microg/g) was much more than that in HCD extract (315.72 microg/g). But on the other hand, HCD was the most efficient for nearly all the highly volatile compounds among the three methods. As to low-volatile compounds such as lactones, long chain aldehydes, ketones, alcohols, and esters, more was detected in SDE extract than in HCD extract. The SD method (322 components, total amount 228.42 microg/g) was the lowest sensitive to all compounds except semi-volatile fatty acids among the three methods.     

Rapid identification of volatile compounds in aromatic plants by automatic thermal desorption — GC-MS

Summary Thermal desorption is a valuable method for the fractionation of plant volatile components, which can be carried out on-line with GC analysis. The use of coupled GC-MS affords additional qualitative information, of special interest for plant species whose composition has not been previously studied. Some examples of the application of automatic thermal desorption, coupled to GC-MS to the identification and characterization of volatile components of plants of different families are given.     

气相色谱-质谱法分析卷烟烟丝和“九曲红梅”红茶样品在加热不燃烧条件下释放出的挥发物及用掺入红茶的烟丝制卷烟的初步探讨

将"九曲红梅"红茶(以下简称红茶)与卷烟烟丝样品分别经过粉碎并通过0.177mm网筛,制成分析用样品。称取0.2mg样品,在裂解炉中,温度为200℃的条件下,在氦气氛围中,样品挥发性成分瞬间气化,由载气带入气相色谱-质谱仪器系统,经分离和测定,得到了两种样品在此条件下所释放出成分。烟丝样品在此加热不燃烧条件下,释放的物质主要有人为添加的发烟剂丙三醇(59.34%),以及其本身的组分烟碱(20.34%)、3-丁炔-1-醇(4.32%)、5-羟甲基糠醛(3.23%)和2,3-二氢-3,5-二羟基-6-甲基-4(H)-吡喃-4-酮(2.12%)等。红茶样品中释放出的主要成分有咖啡因(86.23%)以及16种低含量特征组分。将此红茶样品按质量百分比为5%,10%,30%的比例加入卷烟烟丝中,并测定其在加热不燃烧的条件下释放物质量的变化,并结合感官评价。结果发现:混入不同比例红茶的烟丝,加热后释放出的气体中咖啡因的含量按茶叶的配比量的增加依次为0.71%,1.96%,7.23%;感官评价表明红茶加入卷烟烟丝中,提升了卷烟烟气的优雅感,强化了卷烟的果香、甜香、花香等香韵,提升了香气量和香气丰富性,细腻柔和烟气,改善余味,增强回甜感。当茶叶的加入量为10%时,在余味和口感上有较好的效果,具有全面提升感官品质的功效,整体抽吸舒适性和协调性较好,香气的质和量适中。     

Analytical comparison of different parts of Radix Angelicae Sinensis by gas chromatography coupled with mass spectrometry

The three parts of Radix Angelicae Sinensis (Danggui) were reported to have different therapeutic effects. In order to investigate their chemical compositions of different parts of Danggui, gas chromatography-mass spectrometry (GC-MS) combined with chemometrics data analysis was applied to provide a more detailed study. Subwindow factor analysis (SFA) and a modified augmented evolving window orthogonal projection (AEWOP) method were used to resolve the batch GC-MS data sets from the Danggui samples. Then, t-test, Wilcoxon rank sum test, and principal component analysis (PCA) were applied to carry out the comparison job. The results indicate which components are found to have significant differences among the three parts. These findings may be helpful for further research of the pharmacological activities of Danggui.     

兴安落叶松针叶挥发油的GC-MS和启发渐进式特征投影法分析

采用水蒸气蒸馏法提取兴安落叶松针叶挥发油,利用气相色谱.质谱(GC-MS)联用对挥发油进行成分测定,并对其重叠色谱峰采用启发渐进式特征投影(HELP)法进行分辨,得到各组分的纯色谱峰和质谱,然后采用峰面积归一化法确定各化合物的相对含量.共分离出110种化合物,鉴定了70种化合物,占挥发油总量的93.09%,其中单萜、倍半萜和二萜的含量分别为31.92%、53.29%和6.91%.     

GC–MS法分析茵陈挥发油成分

采用水蒸气蒸馏法提取茵陈中挥发性成分挥发油,用气相色谱–质谱联用技术(GC–MS)对茵陈挥发油成分进行分析鉴定,并采用峰面积归一化法测定其相对含量。共检出52种挥发性成分,鉴定了其中31种主要挥发性成分,含量较高的组分为石竹素(15.27%)、(–)-斯巴醇(6.64%)、石竹烯(4.89%)等。GC–MS法适用于茵陈挥发性成分的定性分析,具有灵敏度高、分析速度快的特点。