多种气相色谱联用技术分析陕西刺五加茎挥发油的化学成分

采用气相色谱/四极杆质谱(GC/qMS)、气相色谱/正交加速飞行时间质谱(GC/oaTOFMS)和气相色谱/傅里叶变换红外光谱(GC/FTIR)联用技术,对一种陕西产刺五加Acanthopanax senticosus (Rupr. et Maxim.) Harms茎挥发油的化学成分进行了分析。基于GC/qMS谱库的检索功能,结合GC/FTIR在结构鉴别上的优势和GC/oaTOFMS对质谱碎片离子精确的质量测定功能,成功地实现了对68个色谱组分的定性分析。与使用单一的联用技术(例如GC/qMS)相比,利用多种色谱联用技术在定性分析上的互补性,可以明显提高对组成复杂的挥发油类样品分析的可靠性。     

Renaissance of gas chromatography-time-of-flight mass spectrometry. Meeting the challenge of capillary columns with a beam deflection instrument and time array detection

This report describes the use of a unique beam deflection time-of-flight mass spectrometer to address some of the demands made on mass spectrometry by new developments in high-resolution capillary column gas chromatography. An integrating transient recorder is used in combination with this beam deflection time-of-flight instrument to apply the concept of time array detection in capturing all of the mass spectral information available from the ion source, thereby greatly enhancing the signal-to-noise ratio quality of the mass spectral data. The applicability of the time array detection approach to gas chromatography-mass spectrometry is demonstrated in the context of an analysis of the standard Grob mixture for assessing performance of capillary column chromatography. During analysis of the Grob mixture by gas chromatography-mass spectrometry, mass spectra were recorded at a rate of 20 scan files per second. The data indicate that this rate of mass spectral scan file generation is adequate to provide a suitable data base for reconstruction of the chromatographic profile. In addition, the effective scan rate is high enough that there is no distortion in the relative peak intensities throughout the individual mass spectra of components regardless of the relatively high dynamic changes in partial pressure of the analyte as reflected by the sharp peaks in the chromatographic profile. The experimental results indicate that the beam deflection time-of-flight mass spectrometer can provide mass spectra at a scan file generation rate much higher than that possible with the conventional quadrupole or magnetic sector mass spectrometer, but at comparable detection limits.     

Analysis of the volatile oil from the stem of Acanthopanax Senticosus (Rupr. et Maxim.) harms with several hyphenated methods of chromatography

Gas chromatography/quadrupole mass spectrometry (GC/qMS), gas chromatography/Fourier transform infrared spectrometry (GC/FTIR) and gas chromatography/orthogonal acceleration time-of-flight mass spectrometry (GC/oaTOFMS) were applied to analyze the volatile oil from the stem of Acanthopanax Senticosus (Rupr. et Maxim.) Harms. Based on the mass spectra search function of GC/qMS with the aid of the discriminability of the geometrical isomer by GC/FTIR and the ability to determine the accurate mass charge ratio (m/z) by GC/oaTOFMS, 68 GC eluants were identified successfully. Compared with the results obtained by GC/qMS only, the analytical results obtained by these hyphenated methods of gas chromatography are more credible. __________ Translated from Chinese Journal of Chromatography, 2005, 23(2)(in Chinese)     

Screening for pesticide residues in oil seeds using solid-phase dispersion extraction and comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry

In this paper, we describe the development of an oil-absorbing matrix solid-phase dispersion extraction with comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry suitable for screening of 68 pesticide residues (PRs) in peanut, soybean, rape seed, sesame, and sunflower seed. The 68 PRs include 27 kinds of organophosphorus, 23 organic chlorines, 11 synthetic pyrethroids, and 7 carbamates. Heptachlor epoxide was used as the internal standard. Aminopropyl silica was chosen as the dispersion sorbent of the oil-absorbing matrix solid-phase dispersion extraction and was applied to capture hydrophobic components from high oil samples. A 35-min orthogonal separation was performed by using comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry with a nonpolar-polar column set. Identification of 68 PRs in the extract was finished by using the time-of-flight mass spectrometry in the assistance of an automated peak-find and spectral deconvolution software. A screening based on control design was introduced and explained. This screening method considerably reduced the cost for the quantitative and confirmatory analyses. The quality of present screening method was evaluated by the Document No. SANCO/10684/2009. The false positive rate and false negative rate provide a useful tool for the evaluation of screening performance.     

二维气相色谱技术及其在烟草行业中的应用

二维气相色谱的应用大大提高了分析能力,而与飞行时间质谱的联用更使其达到一个新的高度。介绍了二维气相色谱的原理、优越性及不足,以及与飞行时间质谱联用的技术进展。综述了近年来该技术在各行业特别在烟草行业中的应用,展望了二维气相色谱在烟草行业中的应用前景。     

Prospects for petroleum mass spectrometry and chromatography

Several recently developed analytical techniques, based on high-end mass spectrometry and chromatography, for dealing with challenges in petroleum characterization are reported. Folded flight path time-of-flight mass spectrometry provides resolving power up to 100000, enabling accurate mass measurement for molecular formula determination with high confidence. Atmospheric pressure chemical ionization (APCI) can be used in both gas chromatography (GC, as APGC) and liquid chromatography (LC) for analyzing non-polar hydrocarbons as well as polar compounds. The improvement in chromatography facilitates the mass spectrometric analysis through online coupling. Comprehensive two-dimensional gas chromatography (GC×GC) resolves overlapping components, rendering accurate identification and quantitation. Supercritical fluid extraction has been developed as an alternative method to replace traditional solvent extraction methods and eliminate the use of large volumes of solvents that can be harmful to health and environment. Supercritical fluid chromatography (SFC) has been developed as a convergence of GC and LC chromatographic techniques. The use of SFC for heavy oils and residua has been demonstrated. Prospective developments in the use of mass spectrometric and chromatographic methods for petroleum characterization are also described.     

Preventive doping control analysis: liquid and gas chromatography time-of-flight mass spectrometry for detection of designer steroids

A new combined doping control screening method for the analysis of anabolic steroids in human urine using liquid chromatography/electrospray ionization orthogonal acceleration time-of-flight mass spectrometry (LCoaTOFMS) and gas chromatography/electron ionization orthogonal acceleration time-of-flight mass spectrometry (GCoaTOFMS) has been developed in order to acquire accurate full scan MS data to be used to detect designer steroids. The developed method allowed the detection of representative prohibited substances, in addition to steroids, at concentrations of 10 ng/mL for anabolic agents and metabolites, 30 ng/mL for corticosteroids, 500 ng/mL for stimulants and beta-blockers, 250 ng/mL for diuretics, and 200 ng/mL for narcotics. Sample preparation was based on liquid-liquid extraction of hydrolyzed human urine, and the final extract was analyzed as trimethylsilylated derivatives in GCoaTOFMS and underivatized in LCoaTOFMS in positive ion mode. The sensitivity, mass accuracy, advantages and limitations of the developed method are presented.     

Beam deflection for temporal encoding in time-of-flight mass spectrometry

The pulsed ion sources used in conventional time-of-flight mass spectrometry (TOFMS) generally do not provide adequate resolving power across the mass range required for applications such as gas chromatography combined with mass spectrometry (GC/MS). Theoretical and experimental aspects of beam deflection techniques, which provide time encoding for TOFMS with continuous ions sources, are explored here. In this approach, ion source conditions do not affect resolving power, allowing for a greater variety of ionization modes to be used. Theoretical predictions for the resolving power attainable with beam deflection, which are satisfactory for GC/MS applications, agree well with experimentally determined values. The combination of GC-beam deflection-TOFMS with time-array detection is evaluated, and the capabilities of this system are compared to those of scanning mass spectrometers.     

全二维气相色谱-飞行时间质谱联用技术分析重馏分油中芳烃组成

通过对升温速度、二维补偿温度、调制周期等关键实验参数的优化,建立了全二维气相色谱-飞行时间质谱(GC×GC-TOF MS)分析重馏分油中芳烃组分的方法,得到了重馏分油芳烃组分按环数分布的二维点阵图。根据谱库检索、标准化合物对照及文献报道,对重馏分油芳烃组分中菲、甲基菲及芘、苯并蒽等常见多环芳烃(PAH)进行了准确定性,并将该方法应用到重馏分油加氢处理工艺研究中,对菲、芘的加氢处理产物进行了定性分析。该研究为重馏分油芳烃组分的准确定性提供了新的技术手段,为加深对油品加氢规律的认识提供了技术支持。全二维气相色谱与普通一维色谱对比,在重馏分油的芳烃组分分析上体现了极大优势。     

Gas chromatography – inductively coupled plasma – time-of-flight mass spectrometry for the speciation analysis of organolead compounds in environmental water samples

The application of inductively coupled plasma – time-of-flight mass spectrometry for the speciation analysis of organolead compounds in environmental waters is described. Construction of the transfer line was achieved by means of a relatively simple and rapid coupling procedure. Derivatization of the ionic lead species was achieved by in-situ propylation with sodium tetrapropylborate; simultaneous extraction of the derivatized compounds in hexane was followed by separation and detection by capillary gas chromatography hyphenated to inductively coupled plasma–time-of-flight mass spectrometry. Detection limits for the different organolead species ranged from 10 to 15 fg (as Pb), corresponding to procedural detection limits between 50 and 75 ng L^–1, on the basis of a 50 mL snow sample, extraction with 200 μL hexane, and subsequent injection of 1 μL of the organic extract on to the column. The accuracy of the system was confirmed by additional analysis of the water samples by capillary gas chromatography coupled with microwave-induced plasma–atomic-emission spectrometry and the analysis of a standard reference material CRM 605 (road dust) with a certified content of trimethyllead.     

Recent advances in mass spectrometric measurement of dioxins

Past years, many efforts have been dedicated to the development of alternative analytical methods for the measurement of dioxins in various types of matrices. Polychlorinated dibenzo-p-dioxins (PCDDs), polychlorinated dibenzofurans (PCDFs), and polychlorinated biphenyls (PCBs) are compounds that are present in samples at part-per-billion (ppb) or part-per-trillion (ppt) level. Their measurement requires the use of very sensitive analytical methods. Gas chromatography (GC) coupled to quadrupole ion storage mass spectrometry (QISTMS), fast GC (FGC) coupled to time-of-flight mass spectrometry (TOFMS) and comprehensive two-dimensional gas chromatography (GC x GC) coupled to TOFMS are the more promising tools challenging the reference GC high resolution mass spectrometry (HRMS) based on sector instruments. We report herein some of the advances we achieved in the past years in our laboratory on the development of alternative measurement methods for those compounds.     

Analysis of Artemisia annua L. volatile oil by comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry

Artemisia annua L. is an annual herb native of Asia, it has been used for many centuries for the treatment of fever and malaria. In this paper, analysis of the volatile oil of Artemisia annua L. was performed by comprehensive two-dimensional gas chromatography time-of-flight mass spectrometry (GC x GC-TOF MS). Three hundred and three components were tentatively identified and terpene compounds are the main components of Artemisia annua L. volatile oil. Artemisinic acid is tentatively qualified.     

An overview of analytical applications of time of flight-mass spectrometric (TOF-MS) analyzers and an inductively coupled plasma-TOF-MS technique.

A brief overview of the applications of time-of-flight mass spectrometry (TOF-MS) for analytical purposes is presented. The performance of TOF-MS combined with an inductively coupled plasma (ICP) ion source is discussed in detail. The advantages of TOF-MS detectors over the quadrupole mass filters for multi-elemental analysis of fast transient signals are discussed. The applications of ICP-TOF-MS for the detection of signals from laser ablation, electrothermal vaporization, gas and liquid chromatography, capillary electrophoresis and flow-injection analysis are reviewed.     

Application potential of microextraction in packed syringe coupled with gas chromatography time-of-flight mass spectrometry in analysis of brominated flame retardants in waste water. Part 2

The article describes the analysis of brominated flame retardants, namely polybrominated diphenyl ethers in wastewater by gas chromatography/time-of-flight mass spectrometry. As a sample preparation method microextraction in packed syringe was used. The possibilities of this method for rapid analysis of water were investigated. It was shown, that this approach minimizes sample handling and reduces time/cost of measurement.     

Early gas chromatography/mass spectrometry

Spectroscopy Laboratory, The Dow Chemical Company, Midland, Michigan, USA In December 1955 or thereabouts, the authors coupled a homemade gas chromatograph to a research time-of-flight mass spectrometer constructed by W. C. Wiley, I. H. McLaren, and D. B. Harrington. This unique gas chromatography/mass spectrometry (GC/MS) instrument generated mass spectra at a lo-kHz rate for display on an oscilloscope; eluted gas chromate graphic components, such as methanol, acetone, benzene, toluene, and carbon tetrachloride, could be visually identified immediately from the oscilloscope display. Many years of further research and development in many laboratories worldwide were necessary, however, to make continuous on-line GC/MS the uniquely valuable analytical tool that it is today.     

薄荷卷烟中香味成分的全二维气相色谱/飞行时间质谱分析

采用全二维气相色谱/飞行时间质谱法(GC×GC/TOFMS),以较长的非极性柱DB-5MS(30m×0.25mm×0.25μm)作为第一维柱,较短的中等极性柱DB-17MS(2m×0.1mm×0.1μm)作为第二维柱,利用固相微萃取法作为香味成分的萃取方法,对薄荷型ESSE卷烟的核心香味成分进行了定性分析,TOFMS谱图库检索结合全二维特有的包含结构信息的二维谱图,通过族分离和结构谱图鉴定,共鉴定了187种挥发性成分,其中对香气有贡献的成分118种.     

Comprehensive multidimensional separation methods by hyphenation of single-photon ionization time-of-flight mass spectrometry (SPI-TOF-MS) with GC and GC×GC

One- and comprehensive two-dimensional gas chromatography were hyphenated with soft photoionization mass spectrometry. The characteristics of these two- and three-dimensional comprehensive separation techniques are discussed in detail. Using the innovative electron beam pumped excimer light source (EBEL) for single-photon ionization (SPI), organic molecules with ionization energies (E _i ) of below 9.8 eV can be detected by a time-of-flight mass spectrometer (TOF-MS). SPI with 126 nm vacuum ultraviolet (VUV) photons enables the universal and soft ionization of organic molecules. SPI-TOF-MS hyphenated to one-dimensional gas chromatography results in a comprehensive two-dimensional separation method (GC×MS). To demonstrate this, diesel fuel was analyzed, and the resulting GC×MS chromatograms are discussed in depth. A three-dimensional separation method was also realized by combining comprehensive two-dimensional gas chromatography (GC×GC) with SPI-MS. In the resulting separation space, constituents originating from mineral oil diesel blended with biodiesel were dispersed along the two GC separation axes, while the molecular mass axis served as a third separation dimension.     

磁搅拌条件下β-环糊精与亚砷酸钠加合物的形成、谱学特性与热分解行为

傅里叶变换利用红外光谱、粉末X射线衍射、微分热重分析、气相色谱-飞行时间质谱、紫外光谱、1H核磁滴定以及电喷雾质谱等分析手段对β-环糊精(β-CD)和亚砷酸钠(SA)形成的分子-离子加合物SA-β-CD进行了详细表征. 结果显示, 主-客体之间分子-离子相互作用是导致SA-β-CD的谱学特性(在固态或在溶液中)与热分解行为相异于主、客体自身行为的重要原因. 而在气相色谱-飞行时间质谱条件下发生的氧化还原反应以及在电喷雾质谱条件下出现的Na+-β-CD(摩尔比为1:1)超分子离子复合体进一步揭示了这种分子-离子加合作用的复杂性与独特性.     

Chemometrics comparison of gas chromatography with mass spectrometry and comprehensive two‐dimensional gas chromatography with time‐of‐flight mass spectrometry Daphnia magna metabolic profiles exposed to salinity

The performances of gas chromatography with mass spectrometry and of comprehensive two‐dimensional gas chromatography with time‐of‐flight mass spectrometry are examined through the comparison of Daphnia magna metabolic profiles. Gas chromatography with mass spectrometry and comprehensive two‐dimensional gas chromatography with mass spectrometry were used to compare the concentration changes of metabolites under saline conditions. In this regard, a chemometric strategy based on wavelet compression and multivariate curve resolution–alternating least squares is used to compare the performances of gas chromatography with mass spectrometry and comprehensive two‐dimensional gas chromatography with time‐of‐flight mass spectrometry for the untargeted metabolic profiling of Daphnia magna in control and salinity‐exposed samples. Examination of the results confirmed the outperformance of comprehensive two‐dimensional gas chromatography with time‐of‐flight mass spectrometry over gas chromatography with mass spectrometry for the detection of metabolites in D. magna samples. The peak areas of multivariate curve resolution–alternating least squares resolved elution profiles in every sample analyzed by comprehensive two‐dimensional gas chromatography with time‐of‐flight mass spectrometry were arranged in a new data matrix that was then modeled by partial least squares discriminant analysis. The control and salt‐exposed daphnids samples were discriminated and the most relevant metabolites were estimated using variable importance in projection and selectivity ratio values. Salinity de‐regulated 18 metabolites from metabolic pathways involved in protein translation, transmembrane cell transport, carbon metabolism, secondary metabolism, glycolysis, and osmoregulation.     

Comprehensive chemical profiling and quantification of Shexiang Xintongning tablets by integrating liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry

Shexiang Xintongning tablet (SXXTN) is a traditional Chinese medicine (TCM) preparation for the treatment of coronary heart disease (CHD) angina pectoris. However, due to the complexity of the compounds in SXXTN, the active chemical components responsible for the therapeutic effect are still ambiguous. The purpose of our study was to characterize the chemical profile of SXXTN and quantify the representative chemicals. The high-performance liquid chromatography coupled with time-of-flight mass spectrometry (HPLC-QTOF MS) method and gas chromatograph coupled with mass spectrometry (GC–MS) method were utilized to identify the chemical constituents of SXXTN. A total of 140 compounds including alkaloids, ginsenosides, organic acids, esters, triterpenes, phthalides and amino acid were identified in accordance with their retention times, accurate masses and characteristic MS/MS fragment patterns. Forty-four volatile components were characterized by GC–MS through NIST database matching. In the further research of quantitative analysis, 40 non-volatile compounds and 17 volatile compounds were determined and successfully applied for detecting in 7 batches of SXXTN samples by high performance liquid chromatography coupled with triple-quadrupole tandem mass spectrometry (HPLC-QQQ MS) and gas chromatograph coupled with triple-quadrupole tandem mass spectrometry (GC-QQQ MS) in multiple reaction monitoring (MRM) mode, respectively. The quantitative methods were verified in linearity, precision, repeatability stability and recovery. The above results indicated that the established method was practical and reliable for synthetical quality evaluation of SXXTN. In addition, our study might supplement the chemical evidence for disclosing the material basis of its therapeutic effects.