直观推导式演进特征投影法对环境样本中多环芳烃的定性定量分析

基于新近发展的直观推导式演进特征投影法(HELP), 本文提出了一个对二维数据进行同时定性定量的分析方法, 并将其成功地用于环境样本中多环芳烃化合物定量解析。对于一维色谱难以定量的重叠峰, HELP方法充分利用色谱、光谱两方面的选择性信息, 得到了具有真实物理意义的唯一解。在定性分辨结果的基础上, 本文还提出了三种可能的定量方法。这种二维数据的解析新方法, 能大幅度地降低对色谱分离条件的要求, 可直接用于复杂实际样本的定性定量分析。     

HELP法在中草药分析中的应用研究-冬虫夏草的化学成分测定

基于直观推导式演进特征投影（ＨＥＬＰ）法,对冬虫夏草子座和虫体分别进行了多组分同时定性定量测定．结果表明,ＨＥＬＰ法能减少样本提取分离的步骤,降低色谱分离条件的要求,提高检测准确度．联用色谱检测与化学计量学解析法相结合将为复杂中草药分析提供一种全新手段     

直观推导式演进特征投影法解析多环芳烃的重叠色谱峰

用高效液相色谱法(HPLC)测定多环芳烃时,因芴、苊和菲,茚(1,2,3-cd)芘和苯并(g,h,i)苝的色谱峰严重重叠而影响测定结果。本研究用高效液相色谱-二极管阵列检测器(DAD)和荧光检测器(FLD)测定多环芳烃,在激发波长λex=230nm,发射波长λem=300～500nm范围内采集重叠峰的HPLC-FLD二维色谱数据,再用直观推导式演进特征投影法(HELP)解析它们的重叠色谱峰,分辨结果令人满意。该方法对重叠组分的分辨下限为0.02mg/L。结果表明,用二维色谱荧光数据解析色谱重叠峰,灵敏度更高,可用于环境样品中多环芳烃的测定。     

高效液相色谱法测定黄浦江表层沉积物中的痕量多环芳烃

建立了高效液相色谱-二极管阵列检测器(PDA)测定上海市黄浦江表层沉积物中16种多环芳烃(PAHs)的方法。在保留时间定性分析的基础上,利用PDA获取的紫外扫描光谱图对目标组分进行了准确的定性,并通过异构体紫外光谱图中特征峰的差异有效地识别了样品中的4种异构体,即苯并［b］荧蒽、 苯并［k］荧蒽、 苯并［a］芘和苯并［e］芘。通过检测波长的优化,减少了干扰物的影响,提高了检测灵敏度;针对分离度较差的两种目标组分(苯并［b］荧蒽和苯并［k］荧蒽)的定量进行了分析讨论。该方法对16种PAHs的检出限(以干基计)介于1.1～18.3 ng/g之间,具有较高的方法灵敏度。黄浦江表层沉积物测定结果表明,除二氢苊外的15种PAHs都被检出,含量为10.1～253.0 ng/g。     

直观推导式演进特征投影法在拖尾重叠色谱峰解析中的应用

直观推导式演进特征投影法(HELP)已成功应用于复杂体系的重叠色谱峰解析.当色谱峰拖尾时,演进特征投影图(ELPG)显示的直线段对应的区域中可能含有前面拖尾组分的信息,据此进行HELP解析可能得不到满意结果.选择ELPG上直线段的一部分,即拖尾组分末端,前面组分的信息已基本消失的区域作为选择性区域进行HELP解析.同时,提出一种新的定量方法:用主成分分析法(PCA)分解待测组分标准样品的二维数据,将得到的“标准”色谱引入HELP的定量过程,在色谱峰拖尾或解得谱峰不平滑时,得到更准确的结果.用HELP方法解析了依诺沙星、诺氟沙星和环丙沙星三组分实验体系,结果表明,加入上述措施的HELP可有效改善拖尾重叠色谱峰的解析结果.     

直观推导式演进特征投影法及其在复杂体系分析中的应用

对直观推导式演进特征投影法(HELP)的原理及主要步骤作了简要介绍。综述了HELP的研究情况及其在中草药分析、环境样品分析等领域中的应用，并对该法的优势和发展趋势作出了讨论。     

唇形科植物挥发油化学成分的GC/MS研究

在运用GC/MS技术的基础上采用HELP(直观推导式演进特征投影法)方法研究了九种唇形科植物的化学成分, 并以唇形科植物半枝莲为例详细介绍了HELP的解析过程. 应用总体积积分法测定各成分的相对百分含量. 鉴定出相对共有成分达70余种, 大多数为萜类化合物及其衍生物. 不同的唇形科植物的挥发油化学成分与特征成分有明显差异. 九种药材挥发性成分中均含有桉油精(Eucalyptol, 含量0.10%～1.01%)和芳樟醇(Linalool, 0.11%～3.05%). 利用GC/MS分析法结合化学计量学分辨方法鉴定挥发油化学成分, 比单独使用GC-MS法结果更准确、可靠.     

气相色谱-质谱法与化学计量学分辨法分析当归须挥发油中化学成分

本文借助化学计量学分辨方法,建立了用气相色谱-质谱(GC-MS)联用法分析当归须挥发油成分的方法.对重叠色谱峰采用直观推导式演进特征投影算法进行分辨,从而获得每一组分的纯色谱和质谱,依靠每一组分纯质谱在NIST质谱库进行相似性检索而定性分析,用总体积积分法进行定量分析.在当归须挥发油中共分辨出86个色谱峰,通过质谱库检...     

Analysis of the Water Soluble Constituents of Cordyceps Sinensis With Heuristic Evolving Latent Projections

ABSTRACT

A chemometric technique, heuristic evolving latent projection (HELP), was applied to analyze the data obtained from high performance liquid chromatography coupled with the diode array detection (HPLC-DAD) for a traditional Chinese medicinal herb, Cordyceps sinensis. Based on this method, the water soluble components, nucleosides in Cordyceps sinensis were identified. Ten and eleven volatile components were identified from the fungal and larvae parts of Cordyceps sinensis sample, respectively. As compared with the conventional method, HELP was found to be suitable for quantitative analysis of complex real systems such as Chinese medicinal products.     

高效液相色谱法测定庆大霉素C组分的不同检测方式测定结果的比较

各国药典中关于庆大霉素C组分的测定方法均为高效液相色谱法,但检测方式及分离效果不同。为此采用直观推导式演进特征投影法(HELP),对高效液相色谱-二极管阵列检测采集的庆大霉素C组分色谱数据进行解析,分辨出各物质的色谱曲线,在扣除了未分离的杂质峰对庆大霉素C1组分的干扰后,对柱前邻苯二醛衍生化-二极管阵列检测法及目前中国药典 2005 版收载的高效液相色谱-蒸发光散射检测方法测定庆大霉素C组分的准确性进行了比较,并运用柱切换技术,证明二者测定结果的一致性。     

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%.     

多次溶剂萃取-气相色谱/串联质谱法测定热熔胶中的多环芳烃

建立了热熔胶中16种多环芳烃( PAHs)的多次溶剂萃取-气相色谱/串联质谱测定方法。详细研究了样品的萃取条件、净化条件和气相色谱/串联质谱测定条件,并与气相色谱-质谱法进行了对比。样品以10 mL正己烷为萃取溶剂,于60℃超声萃取20 min,萃取液依次经冷冻后离心、二甲基亚砜萃取2次、正己烷反萃取2次进行净化,得到的净化液以气相色谱/串联质谱法多反应监测( MRM)模式进行检测。本方法的线性相关系数( R2)均大于0.9969,检出限为1.0~10μg/kg,精密度小于6.3%,16种PAHs的加标回收率为80.4%~117.6%。考察了串联质谱检测的基质效应,发现基质效应不明显。本方法检出限优于气相色谱-质谱法(23~94μg/kg),并能增加定性和定量分析的准确性。本方法灵敏、准确可靠,满足热熔胶中PAHs测试要求。     

Differential scanning calorimetry to measure the purity of polycyclic aromatic hydrocarbons

The application of differential scanning calorimetry (DSC) for purity determination is well documented in literature and is used amongst others in the analysis of pure organic crystalline compounds. The aim of this work is to examine whether the DSC method for purity determination consistently produces values for the purity of polycyclic aromatic hydrocarbons (PAHs) which are sufficiently accurate as required for the certification of reference materials. For this purpose, 34 different existing PAH certified reference materials were tested. The DSC results are shown to be consistent with the results obtained by other methods assessing the organic impurities content in PAHs, like gas chromatography (GC), high performance liquid chromatography (HPLC) and mass spectrometry. Significant differences between the measured values and the certified purity values were observed only in a limited number of cases.     

Development of an improved analytical method for the determination of carcinogenic polycyclic aromatic hydrocarbons in transformer oil

Polynuclear aromatic hydrocarbons (PAHs) are natural constituents of transformer oils and are essential in prolonging transformer in-service lifetime. Issues concerning PAH carcinogenicity demand methods that provide qualitative and quantitative information on the PAH composition of new and in-service oils to allow informed operational decisions to be made. However, current analytical methods focus on PAH fingerprinting, as opposed to quantitative analysis and are also cumbersome, relying on the use of large (>100 ml) volumes of organic solvents, some of which are hazardous. This paper reports a method for the improved quantification of carcinogenic PAHs in transformer oils that is both simple and repeatable. The method uses commercially available solid-phase extraction columns and millilitre volumes of relatively non-hazardous solvents. Extraction efficiencies of > or =74% were obtained for the Environmental Protection Agency priority PAHs. The method has potential for automation and high-throughput analysis and thus is of interest to industries that use transformer oils.     

使用C18固相萃取膜-色质联用定量分析饮用水中痕量多环芳烃的初步研究

参照美国EPA525.1方法,C18-固相萃取膜萃取饮用水中的有机物,利用GC/MS法鉴定多环芳烃(PAHs),使用16种多环芳烃混合标准样绘制标准曲线,以内标法对PAHs进行定量分析.采用本方法研究某水厂经过深度处理后的出厂水中的7种多环芳烃的含量,PAHs的平均回收率为94.0%～97.7%.检测限为0.001μg/L.     

气相色谱-三重四极杆串联质谱法检测环境空气中的多环芳烃

建立了气相色谱-三重四极杆串联质谱检测环境空气中多环芳烃的方法,并利用同位素稀释法对多环芳烃进行了测定。将该方法应用于华南地区某大型石化企业周边环境空气中多环芳烃的检测,并与气相色谱-质谱方法进行了对比。结果表明,该方法的仪器检出限（0.01~0.15 μg/L）和定量限（0.03~1.5 μg/L）均优于气相色谱-质谱法（0.1~0.8 μg/L和0.3~3.5 μg/L）,并有更好的灵敏度与选择性。当利用气相色谱-质谱作为检测手段时,回收率指示物氘代菲和进样内标六甲基苯均受到了杂质的严重干扰,影响了定量结果的准确性,而三重四极杆串联质谱很好地解决了这些问题。实际样品分析时,标准曲线中16种多环芳烃相对响应因子的相对标准偏差为2.60%~15.6%,氘代化合物的回收率为55.2%~82.3%,空白加标样品的回收率为98.9%~111%,平行样品的相对标准偏差为6.50%~18.4%,采样空白含量范围为未检出~44.3 pg/m³,实验室空白含量范围为未检出~36.5 pg/m³。上述研究表明,分析环境空气中的多环芳烃时,气相色谱-三重四极杆串联质谱方法值得推广。     

Essential Oil Composition of Osmanthus fragrans Varieties by GC-MS and Heuristic Evolving Latent Projections

The essential oils from two varieties of Osmanthus fragrans have been extracted by steam distillation and analyzed by gas chromatography-mass spectrometry with the help of heuristic evolving latent projections (HELP), an effective chemometric resolution method. The overlapped peak clusters were resolved into pure chromatograms and pure mass spectra with HELP. Identification of the components was by comparison of temperature-programmed retention indices (PTRIs) and by similarity searches in the National Institute of Standards and Technology mass database. Quantitative results were obtained by overall integration of the peaks. The reliability of the qualitative and quantitative results was greatly improved by using HELP and PTRIs. The main components from O. fragrans Lour. var. thunbergii Mak. (TM) and O. fragrans Lour. var. aurantiacus Mak. (AM) were 1,2-epoxy linalool and nonanal, respectively. In total, 52 volatile components in essential oil of TM and 45 in AM were analyzed qualitatively and quantitatively, accounting for 95.67 and 92.28% total contents of the essential oils.     

Comparison of immunoassay and gas chromatography-mass spectrometry for measurement of polycyclic aromatic hydrocarbons in contaminated soil

Polycyclic aromatic hydrocarbons (PAHs) are frequently encountered in the environment and may pose health concerns due to their carcinogenicity. A commercial enzyme-linked immunosorbent assay (ELISA), was evaluated as a screening method for monitoring PAHs at contaminated sites. The ELISA was a carcinogenic PAH (C-PAH) RaPID assay testing kit that cross-reacts with several PAHs and utilizes benzo[a]pyrene (BaP) as a calibrator. Soil samples were extracted with 50% acetone in dichloromethane (DCM) for analysis by ELISA and gas chromatography-mass spectrometry (GC-MS). The overall method precision was within ±30% for ELISA and within ±20% for GC-MS. Recovery data for spiked soils ranged from 46 to 140% for BaP as determined by ELISA. Recoveries data of the GC-MS surrogate standards, 2-fluorobiphenyl and chrysene, were greater than 70%. The GC-MS procedure detected a total of 19 priority PAHs (2-6-ring PAHs) including seven probable human carcinogens (4-6-ring B2-PAHs). The ELISA results were compared to GC-MS summation results for the total 19 target PAHs as well as for the subset of the seven B2-PAH compounds. For all soil samples, the PAH concentrations derived from ELISA were greater than the sum of B2-PAH concentrations obtained by GC-MS. ELISA determinations were also frequently greater than the results obtained by GC-MS for the total 19 PAH compounds. This discrepancy can be expected, since the ELISA is a screening assay for the detection of several related PAHs while the GC-MS procedure detects priority PAH compounds. Thus, only a subset of PAHs (e.g. 19 PAHs) in the soil samples were measured by GC-MS while additional PAHs, including alkylated PAHs, and PAH derivatives have been demonstrated to be cross-reactive in the C-PAH ELISA. Results of paired tests show that the PAH data from ELISA and GC-MS methods are significantly different (P<0.001), but highly correlated. The ELISA data had a strong positive relationship with the GC-MS summation data for the B2-PAHs as well as for the 19 PAHs targeted by the GC-MS method. Results indicate that the ELISA may be useful as a broad screen for monitoring PAHs in environmental samples.     

Performance evaluation of polycyclic aromatic hydrocarbons analysis in sediment from proficiency testing with metrological reference values

This paper describes a metrological approach to evaluate the measurement capability of laboratories participating in two proficiency testing (PT) programmes involving the analysis of five polycyclic aromatic hydrocarbons (PAHs) in sediment samples. Reference values of PAHs in the programmes for performance assessment were obtained from an accurate isotope dilution gas chromatography mass spectrometry (ID-GCMS) method which was thoroughly validated and verified. Isotope dilution mass spectrometry (IDMS) technique usually has a well-defined measurement uncertainty budget and a traceability link to an International System of Units. Provision of the metrological reference values in PT enables the establishment of a technical platform to assess the actual competence of the participating laboratories in sediment PAHs analysis. Results of the PT programmes showed that about 80 % of the laboratories employed gas chromatography in their analyses and the remaining used liquid chromatography. Irrespective of the techniques being used, however, the majority of the participating laboratories were observed to underestimate values in which the mean values of the five reported PAHs were less than those of the ID-GCMS-derived reference values by 13–20 %. Only 41–44 % of the participating laboratories were able to achieve satisfactory z-scores. The present study revealed that the reinforcement of the capability for accurate measurement of PAHs in sediment samples in laboratories worldwide should be addressed.     

QuEChERS/气相色谱质谱法同时测定膨化食品中多环芳烃类物质

建立了同时测定膨化食品中12种多环芳烃(PAHs)的Qu EChERS/气相色谱三重四极杆质谱(GC-MS/MS)的方法。称取2 g(精确至0.01 g)样品,加入10 mL正己烷提取15 min,采用500 mg乙二胺-N-丙基硅烷化硅胶(PAS)和500 mg C18粉末进行净化,净化后进行GC-MS/MS分析测定。实验结果表明,12种多环芳烃在气相色谱中的分离度良好,在1~1000 ng/mL的浓度范围内线性关系良好。加标回收率测定范围为49%~130%,RSD在1.0%~10%(n=7)之间。检出限在0.20~0.66μg/kg之间,定量限在0.66~2.20μg/kg之间。该方法数据可靠、操作简单快捷、灵敏度高,适合大批量样品中PAHs的测定。