顶空固相微萃取-气相色谱-质谱联用分析纺织品中挥发性有机物

建立了顶空固相微萃取（HSSPME）-气相色谱（GC）-质谱（MS）联用测定纺织品中甲苯、4-乙烯基环己烯、苯乙烯、萘和1-苯基环己烯5种挥发性有机物（VOCs）的分析方法。选择聚二甲基硅氧烷（PDMS）作为萃取涂层,优化了SPME的萃取条件,包括平衡时间、萃取时间、萃取温度、顶空体积、离子强度、搅拌速度、解吸温度和时间以及GC—MS仪器条件。对于甲苯、4-乙烯基环己烯、苯乙烯、萘和1-苯基环己烯方法线性范围分别为0．087～870、3．32～3320、2．28～2280、0．015～150和0．050～50．0ng／g;检出限分别为0．005、0．042、0．670、0．008和0．011ng／g。实际样品加标回收率在80．1％～122％之间,RSD在0．8％～8．6％之间。方法符合纺织品中痕量VOCs的快速分析要求。     

Volatile enrichment on automatic static headspace using a precolumn and stopping the carrier gas flow during injection

The aim of this study was to develop a technique for performing automatic static headspace analysis of volatiles without a cryogenic device. Reconcentration of solutes was accomplished using a graphitized carbon coated precolumn between two splitting points and stopping carrier gas flow during injection. Chromatographic profiles of volatile compounds from ground coffee compared with split and splitless injections provide confirmation of the good sensitivity of the technique. The analysis of a standard mixture covering a wide range of volatility confirms that the described technique might be useful to achieve enrichement of low volatile headspace compounds, even if discrimination against the various components is present.     

Modified capillary GC/MS system enabling dynamic headspace sampling with on-line cryofocusing and cold on-column injection of liquid samples

The paper describes a capillary GC/MS hardware arrangement allowong either:

• (a) on-line injection of sample of gases and vapors coming from dynamic headspace or purg & trap samplers and their subsequent cryofocusing/thermal desorption prior to the analytical capillary column (first column):
• (b) direct injection of liquid samples through a cold on-column injector into a second analytical column (counted in series with the first).

Chromatographic profiles of acacia honey aromas provide condirmation of the suitability of this system.     

Use of headspace capillary GC to study the development of volatile compounds in fresh fruit

The composition of volatile compounds produced by fruit during growth and post-harvest storage and ripening has been studied and the different headspace methods compared. Static and dynamic headspace sampling have been compared and evaluated according to their capacity to collect and concentrate volatiles from the atmosphere surrounding the fruits, and FID, MSD, and organoleptic detection have been compared. The results emphasize that the headspace sampling procedure selected is crucial to the performance of subsequent analysis.     

佩兰挥发性化学成分的固相微萃取研究

采用固相微萃取-气相色谱-质谱法分析佩兰中挥发性化学成分,共分离出84个组分,并鉴定了67个组分,用归一化法测定其质量分数,占总挥发性组分峰面积的98.05%。主要成分是对-伞花烃(5.19%)、芳樟醇(3.72%)、β-石竹烯(12.35%)、α-律草烯(13.39%)、α-姜黄烯(2.11%)、(-)-石竹烯氧化物(8.25%)、. /-.-4-乙酰基-1-甲基环己烯(8.91%)。     

顶空固相微萃取-气质联用技术分析5种荷花的挥发性成分

采用顶空固相微萃取-气相色谱质谱联用(HS-SPME-GC-MS)技术分析测定了5个品种荷花中的挥发性成分.考察了不同萃取头和萃取温度对荷花挥发性成分萃取的影响,选用65μm PDMS/DVB SPME萃取头和25℃室温萃取荷花中的挥发性成分得到较好的萃取效果.应用峰面积归一化法测定各挥发性成分的相对含量,5个品种共鉴...     

Quantitative analysis of volatile selenium metabolites in normal urine by headspace solid phase microextraction gas chromatography-inductively coupled plasma mass spectrometry

The combination of headspace-solid phase microextraction (HS-SPME) and gas chromatography-inductively coupled plasma mass spectrometry (GC-ICPMS) was evaluated for the determination of volatile selenium metabolites in normal urine samples, i.e. without selenium supplementation. HS-SPME operating conditions were optimised and a sampling time of 10 min was found to be suitable for simultaneous extraction of dimethylselenide (DMSe) and dimethyldiselenide (DMDSe). The amount of DMSe and DMDSe extracted onto fibre coating was calculated in clean matrix, i.e. Milli-Q water, on the basis of depletion experiments. When applied to normal urine samples, the developed method allowed the detection of four volatile selenium containing species, among which DMSe and DMDSe could be quantified by standard additions.     

GC-MS分析大叶金花草中挥发性成分和脂肪酸

应用 GC-MS 联用技术对大叶金花草(Stenoloma chusana(L.)Ching)的挥发性成分和脂肪酸进行了检测,共检测出7种挥发性成分和32种脂肪酸,脂肪酸检出量为87.65%,其中饱和脂肪酸占脂肪酸总量的53.13%,不饱和脂肪酸占脂肪酸总量的46.87%.该研究为大叶金花草的进一步开发利用提供了科学依据.     

Analysis of volatile secondary metabolites from Colombian Xylopia aromatica (Lamarck) by different extraction and headspace methods and gas chromatography

Hydrodistillation (HD), simultaneous distillation-solvent extraction (SDE), microwave-assisted hydrodistillation (MWHD), and supercritical fluid (CO2) extraction (SFE), were employed to isolate volatile secondary metabolites from Colombian Xylopia aromatica (Lamarck) fruits. Static headspace (S-HS), simultaneous purge and trap (P&T) in solvent (CH2Cl2), and headspace (HS) solid-phase microextraction (SPME) were utilised to obtain volatile fractions from fruits of X. aromatica trees, which grow wild in Central and South America, and are abundant in Colombia. Kováts indices, mass spectra or standard compounds, were used to identify more than 50 individual components in the various volatile fractions. beta-Phellandrene was the main component found in the HD and MWHD essential oils, SDE and SFE extracts (61, 65, 57, and ca. 40%, respectively), followed by beta-myrcene (9.1, 9.3, 8.2 and 5.1%), and alpha-pinene (8.1, 7.3, 8.1 and 5.9%). The main components present in the volatile fractions of the X. aromatica fruits, isolated by S-HS, P&T and HS-SPME were beta-phellandrene (53.8, 35.7 and 39%), beta-myrcene (13.3, 12.3 and 10.1%), p-mentha-1(7),8-diene (7.1, 10.6 and 10.4%), alpha-phellandrene (2.2, 5.0 and 6.4%), and p-cymene (2.2,4.7 and 4.4%), respectively.     

Analysis of volatile aromatic compounds in gasoline-contaminated ground water samples by static headspace sampling and high speed gas chromatography

A 15 second, high speed, gas chromatographic determination has been performed on the volatile aromatic compounds in gasoline-contaminated ground water following manual, static headspace sampling. Retention time reproducibility of the seven peaks studied ranged from 0.25 to 0.67 per cent (average relative standard deviation). Excellent linear correlations were obtained for plots of either peak height or peak area against the concentration of the compounds. Comparison was made between the results obtained from the analysis of three replicate samples of gasoline-contaminated ground water by the high speed GC, by two field-portable GCs, and by a laboratorybased GC. It is worthy of note that all the high speed GC analyses required for this study were accomplished in one day.     

Cryofocusing in the combination of gas chromatography with equilibrium headspace sampling

Summary When headspace gas chromatography utilizing capillary columns is used for trace analysis, sample enrichment is often needed. This involves splitless sample injection of fairly large gas volumes and relatively long sampling times. As a result of this, the band of the sample vapor may be too large causing peak distortion and poor resolution. This problem can be easily overcome by the use of cryogenic trapping. While this can be accomplished by cooling the whole column to subambient temperature during sample introduction, a more convenient way is to utilize part of the first coil of the capillary column as a cryogenic trap.The paper discusses the theoretical background and instrumentation of cryogenic trapping and demonstrates the possibilities through a number of examples.Enlarged text of a paper presented at the 37th Pittsburgh Conference on Analytical Chemistry and Applied Spectroscopy, Atlantic City, NJ, March 10–14, 1986.     

气相色谱-质谱法分析啤酒中酒花香气成分

利用顶空固相微萃取-气相色谱质谱技术(HS-SPME/GC-MS)建立了定量分析啤酒中19种源自酒花的微量香气成分的方法。研究了不同萃取头、萃取时间、萃取温度对萃取效果的影响,最终确定HS-SPME最佳萃取条件为采用PDMS萃取头对啤酒样品在50℃下萃取60 min。在最佳萃取条件下,采用啤酒为基体以减少基体干扰,建立标准曲线,随后在SIM模式下以萜品烯-4-醇为内标定量测定了啤酒中酒花香气物质的含量。19种物质的回收率在81.2%～116.8%之间,相对标准偏差(RSD)低于9.8%,在5个加标浓度下,R2大于0.99。相比于传统方法,本方法所需样品量少、灵敏度高、操作过程简便,能准确的检测出啤酒中酒花香气物质的含量。     

Validation of a headspace trap gas chromatography and mass spectrometry method for the quantitative analysis of volatile compounds from degraded rapeseed oil

Due to lipid oxidation, off‐flavors, characterized by a fishy odor, are emitted during the heating of rapeseed oil in a fryer and affect the flavor of rapeseed oil even at low concentrations. Thus, there is a need for analytical methods to identify and quantify these products. To study the headspace composition of degraded rapeseed oil, and more specifically the compounds responsible for the fishy odor, a headspace trap gas chromatography with mass spectrometry method was developed and validated. Six volatile compounds formed during the degradation of rapeseed oil were quantified: 1‐penten‐3‐one, (Z)‐4‐heptenal, hexanal, nonanal, (E,E)‐heptadienal, and (E)‐2‐heptenal. Validation using accuracy profiles allowed us to determine the valid ranges of concentrations for each compound, with acceptance limits of 40% and tolerance limits of 80%. This method was then successfully applied to real samples of degraded oils.     

Static headspace versus head space solid-phase microextraction (HS-SPME) for the determination of volatile organochlorine compounds in landfill leachates by gas chromatography

The determination of five volatile organochlorine compounds, VOX (chloroform, 1,1,1-trichloroethane, carbon tetrachloride, trichloroethene and tetrachloroethene) in raw landfill leachates and biologically cleansed leachates by GC-MS is investigated. Two extraction and preconcentration procedures were evaluated for recovery of such analies from the samples, including static headspace (HS) and solid phase microextraction by sampling the headspace above the sample (HS-SPME). Optimisation of operating parameters for the best performance of both, sampling and preconcentration techniques was described. Detection limits, time of analysis, precision and linear ranges of both introduction techniques have been established. Application of proposed methods to the determination of the five VOX under study in the above referred samples revealed the absence of such analytes in both leachates. Then both methods were applied to the determination to the five organochlorine compounds under study on spiked leachates samples. While HS-GC-MS offered better analytical precision than HS-SPME-GC-MS, this last technique gave a faster analytical response because no dilution must be done for a reliable VOX determination in landfill leachates. In any case, both sample introduction techniques tested provides excellent recoveries and good analytical precision (ranged from 1 to 3%).     

Determination of HCN sampled from gasification product gases by headspace gas chromatography with atomic emission detector

Nitrogen-containing fuels produce hydrogen cyanide when the fuel is gasified. The gas is poisonous and produces nitrogen oxides when it is burned. HCN is usually sampled into alkaline solutions and analysed using an ion selective electrode. The method is tedious and the electrode response is temperature-dependent. Samples are not stable and must be analysed immediately, and they contain ions which are poisonous to the electrode. Therefore a new gas chromatographic method was developed. In this new method HCN is released from the alkaline solutions with sulphuric acid in a headspace sampler and analysed by a gas chromatograph connected to an atomic emission detector. Measurements on carbon emission line 193.1 nm gave the limit of detection 0.05 mg CN^–/l in the solution. The calibration curve was linear to 1000 mg CN^–/l and the correlation was 0.997. The relative standard deviation of the calibration was 1.7% at the concentration of 5 mg CN^–/l and 1.0% at 25 mg CN^–/l. The developed headspace method allows automated analysis and it needs less sample preparations than the ion selective electrode method. This paper also reports the effect of sample preparation and storage time on the stability of the samples.     

阿育魏实挥发油成分的GC-MS分析

采用水蒸气蒸馏的方法提取了阿育魏实挥发油,并利用气相色谱一质谱联用技术对其化学成分做了分析,共鉴定出麝香草酚、β-伞花烃、萜品烯、α-崖柏烯、β-月桂烯和香芹酚等53个化合物。研究阿育魏实挥发油的成分,对民族药品质提升及原料的质量保证具有十分重要的意义。     

Analysis of volatile organic compounds in pleural effusions by headspace solid‐phase microextraction coupled with cryotrap gas chromatography and mass spectrometry

Headspace solid‐phase microextraction coupled with cryotrap gas chromatography and mass spectrometry was applied to the analysis of volatile organic compounds in pleural effusions. The highly volatile organic compounds were separated successfully with high sensitivity by the employment of a cryotrap device, with the construction of a cold column head by freezing a segment of metal capillary with liquid nitrogen. A total of 76 volatile organic compounds were identified in 50 pleural effusion samples (20 malignant effusions and 30 benign effusions). Among them, 34 more volatile organic compounds were detected with the retention time less than 8 min, by comparing with the normal headspace solid‐phase microextraction coupled with gas chromatography and mass spectrometry method. Furthermore, 24 volatile organic compounds with high occurrence frequency in pleural effusion samples, 18 of which with the retention time less than 8 min, were selected for the comparative analysis. The results of average peak area comparison and box‐plot analysis showed that except for cyclohexanone, 2‐ethyl‐1‐hexanol, and tetramethylbenzene, which have been reported as potential cancer biomarkers, cyclohexanol, dichloromethane, ethyl acetate, n‐heptane, ethylbenzene, and xylene also had differential expression between malignant and benign effusions. Therefore, the proposed approach was valuable for the comprehensive characterization of volatile organic compounds in pleural effusions.     

Multiple headspace extraction-capillary gas chromatography (MHE-CGC) for the quantitative determination of volatiles in contaminated soils

A multiple headspace extraction-capillary gas chromatographic method for the quantitative, accurate, and rapid determination of volatiles in multicontaminated soil samples has been developed. A thick film fused silica column has been used and a nine-step multiple headspace extraction (MHE) determination performed. Calibration was achieved by introducing 1 μl of a standard solution of mixed volatiles into empty headspace vials, the presence of the matrix being unnecessary in multiple headspace extraction. Accuracy of determination by MHE-CGC and a simple method employing standard additions have been compared.     

Dynamic headspace analysis of trace volatile components in polymeric materials by wide bore capillary gas chromatography

A novel dynamic headspace gas chromatographic system equipped with a wide bore capillary column was constructed for direct analysis of less volatile components in polymeric materials such as coating paints. With this system, the determination of typical paint additives such as hindered amine light stabilizers and ultraviolet absorbers could be carried out within a short time.     

固相微萃取-气相色谱-质谱法分析香樟籽挥发性成分

采用固相微萃取-气相色谱-质谱法分离和鉴定香樟籽的挥发性成分,用归一化法测定其相对含量。共分离出76种组分,鉴定出47种化合物,其含量占总挥发性成分的97.4%。主要挥发成分为樟脑(57.89%)、柠檬烯(12.68%)、α-蒎烯(4.42%)、莰烯(2.69%)、香橙烯(2.34%)、伞花烃(2.26%)及β-蒎烯(2.12%)。