头发中内源性类固醇激素的气相色谱-串联质谱分析

建立了建康人头发中内源性类固醇兴奋剂睾酮、表睾酮、雄酮、苯胆烷醇酮和脱氢表雄酮的气相色谱-串联质谱(GC-MS/MS)分析方法。头发经碱水解后,以乙醚提取,经衍生化后采用GC-MS/MS的多反应监测模式(MRM)分析。方法的线性关系良好,检出限达0.1～0.2 pg/mg;提取回收率为74.6%～104.5%;日内测定的准确度为90.1%～113.7%,日内及日间测定的精密度均小于17.5%。应用所建立的方法测定了80例中国健康人头发中睾酮、表睾酮、雄酮、苯胆烷醇酮和脱氢表雄酮的生理水平,为内源性类固醇兴奋剂滥用的判断提供了方法和基础数据。     

Identification of volatile components in Angelica species using supercritical-CO2 fluid extraction and solid phase microextraction coupled to gas chromatography-mass spectrometry

As a part of our search for environmentally friendly solvents to extract the active components of medicinal plants, two sampling techniques, supercritical fluid extraction (SFE) using CO(2) and solid-phase microextraction (SPME) were compared for their efficacy in the analysis of volatiles rhizome components emitted from the medicinal herbs Angelica gigas NAKAI (Korean danggui), Angelica sinensis (Chinese danggui), and Angelica acutiloba (Japanese danggui). A total of 54 compounds released from all of these varieties of Angelica rhizomes were separated and identified by gas chromatography-mass spectrometry (GC-MS). The composition of supercritical extracts from these plants was very different from the solid-phase microextraction products. More compounds were detected by SPME-GC-MS (41) than by SFE-GC-MS (17). The results of these analyses suggest that SFE may be useful for detecting the main components, decursinol angelate and decursin in Korean danggui, and butylidene dihydro-phthalide in both Chinese and Japanese danggui, whereas the results for SPME did not. The SFE method required specialized instrumentation, required little time to prepare the sample, and had a small sample size and no organic solvent. In sum, these results suggest that SFE is useful for extracting the volatile main components of danggui cultivars. Its simplicity, low cost and speed may allow SPME to increase the recovery of volatile components in general without disturbing the main components of the plant.     

土壤中64种痕量半挥发性有机污染物的分析方法研究

利用超声提取技术将土壤中的半挥发性有机污染物(SVOC)提取出来, 经旋转蒸发浓缩至一定体积后, 用ODSC18柱净化, 再用氮吹浓缩后, 取1.0 μL注入气相色谱中, 用DB-5 ms柱分离, 用气相色谱质谱仪(GC-MS)进行定性定量分析. 本方法研究土壤中64种半挥发性有机污染物, 其中包括苯系物、苯酚类、苯胺类、硝基芳香烃类、氯代芳烃类、多环芳烃类和酞酸酯类等物质的提取、净化方法以及回收率、精密度和检测限的测定. 该方法回收率为52.5%～105%.     

Determination of estrone and 17 beta-estradiol in human hair by gas chromatography-mass spectrometry

An efficient procedure is described for the determination of estrone and 17 beta-estradiol in hair by gas chromatography-mass spectrometry (GC-MS). The method involves alkyloxycarbonylation with isobutyl chloroformate (isoBCF) of phenolic hydroxy groups after alkaline digestion of hair samples. The resulting isobutyloxycarbonyl derivatives of estrone and 17 beta-estradiol are extracted with hexane and subjected to chlorodifluoroacetyl derivatization in order to protect the remaining alcoholic hydroxy groups. When GC-MS with selected ion monitoring (SIM) was used, the quantitative ions were at m/z 270 and 384 in the electron ionization mass spectra for estrone and 17 beta-estradiol, respectively. The detection limits for SIM of the steroids were 1 and 2 pg, respectively, and the SIM responses were linear with correlation coefficients varying from 0.991 to 0.994 in the concentration range 0.2-4.0 ng g-1 for the estrogens studied. The detection of estrone and 17 beta-estradiol in hair samples was possible in the concentration range of 0.24-1.30 ng g-1. The concentrations of the two estrogens detected were different in male and female hair samples.     

超临界萃取中药白芷的化学成分的气相色谱质谱分析

采用超临界流体萃取法对传统中药白芷的化学成分进行了分离提取研究，利用气相-质谱联机技术，对其中的55种化学成分进行了鉴定，并测定了相对含量。与传统的水蒸气蒸馏法提取的白芷挥发油进行了比较，分析。实验结果表明，超临界CO2萃取法所得的产物，能保留药材白芷的所有有效成分，可以入药。     

气相色谱-串联质谱法测定食用油中两种非邻苯二甲酸酯类增塑剂

建立了气相色谱-串联质谱同时测定食用油中对苯二甲酸二（2-乙基己基）酯和偏苯三甲酸三（2-乙基己基）酯两种非邻苯二甲酸酯类增塑剂的方法。样品采用乙腈提取,于-20℃冷冻除脂净化,用气相色谱-串联质谱选择反应监测模式测定。两种化合物的检出限为0.03 mg/kg,定量限为0.1 mg/kg,线性范围为0.1~10 mg/kg。3个添加水平（0.1、0.3和1.0 mg/kg）下的回收率为81.04%~108.31%,相对标准偏差为0.70%~9.91%。该方法简便、准确,适用于食用油中对苯二甲酸二（2-乙基己基）酯和偏苯三甲酸三（2-乙基己基）酯的检测。     

气相色谱-质谱法测定植物源性食品中残留的联苯菊酯

建立了气相色谱-质谱检测8种植物源性食品中联苯菊酯残留量的方法。粮谷类样品采用乙腈提取、凝胶渗透色谱（GPC）结合Florisil固相萃取柱净化;蔬菜类样品采用乙酸乙酯提取、Florisil固相萃取柱净化,然后采用气相色谱-质谱测定,选择离子监测模式检测。方法的检出限为5 μg/kg（S/N=10）;在0.005～0.5 mg/L范围内呈现良好的线性关系,相关系数为0.9999;在0.005,0.04和0.1 mg/kg 3个添加水平下,联苯菊酯的添加回收率在74%～99%之间,相对标准偏差(RSD)小于13%。该方法灵敏度高,净化效果良好,能有效地消除复杂基质带来的干扰,可以作为日常样品中联苯菊酯残留量的检测和确证方法。     

Determination of terbinafine (Lamisil) in human hair by microbore liquid chromatography/tandem mass spectrometry

An analytical method for the determination of terbinafine (Lamisil(R)) in human hair was developed and validated. Human hair (10 mg) was hydrolyzed in 0.50 mL of 5.0 N sodium hydroxide for 1.5 h. The aqueous layer was extracted with 1.5 mL of n-hexane. The organic layer was separated and re-extracted with 0.20 mL of formic acid (12.5%)/2-propanol (85:15, v/v). The aqueous layer was separated and 0.010 mL of the aqueous extract was injected onto a reversed-phase microbore (50 x 1.0 mm i.d.) column for analysis by liquid chromatography/tandem mass spectrometry (LC/MS/MS). The instrument was equipped with an electrospray ionization (ESI) interface and operated in the positive ion mode of detection. Interday and intraday accuracy and precision were assessed from the relative recoveries of spiked samples analyzed on three different days. The method showed excellent specificity and ruggedness with a lower limit of quantitation of 10 ng/g (i.e., 10 ppb) using 10 mg of human hair.     

Determination of polybrominated diphenyl ethers in domestic dust by microwave-assisted solvent extraction and gas chromatography-tandem mass spectrometry

In this paper, a rapid and simple method for the analysis of polybrominated diphenyl ethers (PBDEs) in house dust samples based on microwave-assisted solvent extraction (MASE) and gas chromatography-tandem mass spectrometry (GC-MS/MS) is presented. Extraction conditions were optimized using a multifactorial experimental design approach. The use of an aqueous NaOH phase in combination with a non-polar organic phase (hexane) to extract the target analytes from dust allowed an efficient extraction and reduced chromatographic background. The final hexane extracts could be analyzed after a simple one-step cleanup procedure using Florisil. The validation of the method was performed in terms of accuracy, linearity, and repeatability. The limits of detection (LODs) ranged from 0.29 to 0.55 ng/g for all compounds. The target PBDEs were found in several real dust samples collected in urban and rural houses of Northwestern Spain.     

Trace analysis of pesticide residues in water by high-speed narrow-bore capillary gas chromatography-mass spectrometry with programmable temperature vaporizer

A method for the rapid trace analysis of 17 residual pesticides in water by narrow-bore capillary (I.D. 100 microm) gas chromatography-mass spectrometry (GC-MS) using a programmable temperature vaporizer (PTV) was discussed. The method consisted of a large-volume injection (40 microl) by a PTV, high-speed analysis using a narrow-bore capillary column and MS detection. The PTV with solvent vent mode was very useful for large-volume injection into a narrow-bore capillary column because the injected solvent volume could be reduced to less than 2 microl. The analysis time was 8.5 min [less than 50% of the analysis time using conventional columns (I.D. 250 microm)]. A 10-ml volume of river water was extracted by dichloromethane (4 ml), and then the extract was condensed to 1 ml. This extract was analyzed. Mean recoveries for river water spiked at 100 pg/ml ranged from 83.4 to 96.7%. The limit of detections of the 17 pesticides ranged from 1 to 100 pg/ml.     

Aromatic resin characterisation by gas chromatography-mass spectrometry. Raw and archaeological materials

An analytical procedure based on alkaline hydrolysis, solvent extraction and trimethyl-silylation followed by gas chromatography-mass spectrometry (GC-MS) analysis was used to study the chemical composition of benzoe and storax resins, water-insoluble exudates of trees of the Styrax and Liquidambar genus. They are chemically characterised by having aromatic acids, alcohols and esters as their main components and are thus known as aromatic and/or balsamic resins. This analytical procedure allowed us to characterise the main components of the two resins and, even though cinnamic acid is the main component of both the resins, the presence of other characteristic aromatic compounds and triterpenes permitted us to distinguish between the two materials. All the compounds identified in benzoe resin were detected in an archaeological organic residue from an Egyptian ceramic censer (fifth to seventh centuries a.d.), thus proving that this resin was used as one of the components of the mixture of organic materials burned as incense. These results provide the first chemical evidence of the presence of benzoe resin in an archaeological material from Mediterranean area.     

Determination of isophorone in food samples by solid-phase microextraction coupled with gas chromatography-mass spectrometry

A simple and sensitive method for the determination of isophorone in food samples was developed by headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS). Isophorone was separated within 10 min by GC-MS using a DB-1 capillary column and detected with selective ion monitoring mode. The HS-SPME using a polydimethylsiloxane/divinylbenzene (PDMS/DVB) fiber provided effective sample enrichment, and was carried out by fiber exposition at 60 degrees C for 45 min. The extracted isophorone was easily desorbed by fiber exposition in the injection port of a capillary GC-MS system, and carryover was not observed. Using this method, the calibration curve of isophorone was linear in the range 20-1000 pg/mL, with a correlation coefficient 0.9996 (n = 18), and the detection limit (S/N = 3) was 0.5 pg/mL. The HS-SPME/GC-MS method showed 25,000-fold higher sensitivity than the direct injection method (1 microL injection). The within-day and between-day precisions (relative standard deviations) at the concentration of 1 ng/mL isophorone were 3.9% and 6.1% (n=5), respectively. This method was successfully applied to the analysis of food samples without interference peaks. The recoveries of isophorone spiked into food sample were above 84% for a 50 or 500 pg/mL spiking concentration. The analytical results of the contents of isophorone in various food samples were presented.     

Determination of polybrominated diphenyl ethers in human hair by gas chromatography-mass spectrometry

A rapid analytical method has been developed for the determination of polybrominated diphenyl ethers (PBDEs) in human hair. PBDEs were determined by gas chromatography with electron ionization mass spectrometric detection in the selected ion monitoring mode (GC-MS-SIM). A 200 mg amount of hair samples was overnight digested in 3N HCl and then PBDEs extracted with n-hexane. After clean up of extracts in a Florisil column, PBDEs were analyzed by GC-MS. The method has been validated by spiking human hair at five concentration levels, in the range from 5 to 25 ng/g for most compounds, and PBDEs were quantified using labelled compounds as internal standards. Recoveries of PBDEs were higher than 90%, repeatability was equal or lower than 12.5%, and reproducibility lower than 14%, expressed as relative standard deviation (RSD). Limits of detection (LOD) were in the range 0.08-0.9 ng/g and limits of quantification (LOQ) were between 0.27 and 3.0 ng/g. This method was applied to the determination of PBDEs in hair samples from 16 individuals and 5 PBDE congeners were detected in most of the samples. BDE-209 was the dominant compound found, followed by BDE-47, BDE-99, BDE-100, and BDE-190. BDE-209 was found in 12 out of 16 hair samples, and the total levels of PBDEs ranged from 1.4 to 19.9 ng/g.     

Identification of novel synthetic organic compounds with supersonic gas chromatography-mass spectrometry

Several novel synthetic organic compounds were successfully analyzed with a unique type of GC-MS titled Supersonic GC-MS following a failure in their analysis with standard GC-MS. Supersonic GC-MS is based on interfacing GC and MS with a supersonic molecular beam (SMB) and on electron ionization of sample compounds as vibrationally cold molecules while in the SMB, or by cluster chemical ionization. The analyses of novel synthetic organic compounds significantly benefited from the extended range of compounds amenable to analyses with the Supersonic GC-MS. The Supersonic GC-MS enabled the analysis of thermally labile compounds that usually degrade in the GC injector, column and/or ion source. Due to the high carrier gas flow rate at the injector liner and column these compounds eluted without degradation at significantly lower elution temperatures and the use of fly-through EI ion source eliminated any sample degradation at the ion source. The cold EI feature of providing trustworthy enhanced molecular ion (M+), complemented by its optional further confirmation with cluster CI was highly valued by the synthetic organic chemists that were served by the Supersonic GC-MS. Furthermore, the provision of extended mass spectral structural, isomer and isotope information combined with short (a few minutes) GC-MS analysis times also proved beneficial for the analysis of unknown synthetic organic compounds. As a result, the synthetic organic chemists were provided with both qualitative and quantitative data on the composition of their synthetic mixture, and could better follow the path of their synthetic chemistry. Ten cases of such analyses are demonstrated in figures and discussed.     

Comparison of gas chromatography-mass spectrometry and capillary electrophoresis in analysis of phenolic compounds extracted from solid matrices with pressurized hot water

Self-constructed pressurized hot water extraction (PHWE) equipment was used in dynamic mode to extract spiked phenolic compounds (phenol, 3-methylphenol, 4-chloro-3-methylphenol and 3,4-dichlorophenol) from sea sand and soil. Phenols were analyzed by both gas chromatography-mass spectrometry (GC-MS) and capillary zone electrophoresis (CZE) to compare the techniques and to find out if CZE is a suitable tool for analysis of phenols extracted from environmental matrix. Good recoveries of phenols spiked in sea sand were achieved at all PHWE temperatures (50, 100, 200, 300 C). GC-MS studies showed that phenols were selectively extracted from soil at 50 C but various other compounds (e.g. polyaromatic hydrocarbons) were extracted along with the phenols at 300 degrees C. In the case of CZE, phenols extracted from the soil, at 300 C were separated with good resolution at pH 9.7, and co-extracted compounds did not interfere with the analysis. The analytical values obtained by GC-MS and CZE were generally of similar magnitude.     

An objective comparison of pre-processing methods for enhancement of liquid chromatography-mass spectrometry data

Four data pre-processing methods have been applied with different settings to data sets obtained from the analysis of a pharmaceutical drug and its degradation products by liquid chromatography-mass spectrometry (LC-MS). The methods compared were the frequently used component detection algorithm (CODA) and three kinds of digital filters--matched filtration (MF), Gaussian second derivative (GSD) and Savitzky-Golay. The aim was to evaluate the performance and robustness of these methods for extracted ion chromatogram (XIC), total ion chromatogram (TIC) and base peak chromatogram (BPC) in the presence of different types of noise. In accordance with theory, the best improvements in signal-to-noise ratio (S/N) of the XICs were obtained with MF under the ideal case with random white noise. However, when highly coloured noise was present, it was found that no improvements in XIC S/N could be obtained with any of the pre-processing methods studied. GSD and CODA did, however, improve the S/N for both TIC and BPC. GSD and CODA also significantly reduced the background in the spectral domain, thereby facilitating the interpretation of the mass spectra. Another advantage associated with CODA and to some extent also with GSD is their data reduction ability.     

Supercritical fluid extraction of vapor-deposited pyrene from carbonaceous coal stack ash

The efficiencies of extraction of vapor-deposited pyrene from a high-carbon coal stack ash by Soxhlet extraction with methanol, ultrasonic extraction with toluene, acid pretreatment and subsequent ultrasonic extraction with toluene, batch extraction with toluene, and supercritical fluid extraction (SFE) are compared. SFE using CO(2) or isobutane yielded extraction recoveries virtually identical with those obtained using ultrasonic or Soxhlet extraction processes. Collection of the SFE extract was performed by expansion into a solvent or onto the head of a gas chromatography (GC) column. No loss of extracted pyrene was observed upon collection of methanol-modified CO(2) SFE by expansion into methanol. Also, no loss of pure CO(2) SFE extract was observed upon collection on the head of a GC column. However, use of a methanol or toluene modifier for CO(2) SFE directly coupled to GC effected complete loss of extracted pyrene.     

GC-MS of volatile components of Schisandra chinensis obtained by supercritical fluid and conventional extraction

In this paper, the volatile compounds of Schisandra chinensis obtained by different extraction techniques including supercritical fluid extraction (SFE), steam distillation (SD), Soxhlet extraction (SE) and ultrasound-assisted extraction (UAE) were investigated for the first time. The sample preparation procedure for GC-MS analysis of the volatile compounds was optimized and then 37, 45, 27 and 37 compounds were identified in the samples obtained by SFE, SD, SE and UAE methods, respectively. As the therapeutic effect of the traditional Chinese medicine is usually based on multifarious essential components or the combination of them instead of only one component, the volatile compounds were compared in groups with the extracts by SE, SD and UAE. This would be more reasonable to evaluate the effects of an alternative technique to extracting multifarious essential components. Among the identified components in the SFE extract, 32 compounds were the same as that by three conventional methods, accounting for 90.5% of the volatile compounds identified. However, as the volatile compounds were classed into groups, it was easy to see that the Schisandra chinensis oil extracted by SFE was made up largely of aromatics and sesquiterpenoids (52.1 and 27.6%, respectively), with less amounts of monoterpenoids and other compounds, distinguishing SFE from the conventional extractions.     

Simultaneous determination of phenolic acids and 2,4-dihydroxy-7-methoxy-1,4-benzoxazin-3-one in wheat (Triticum aestivum L.) by gas chromatography-tandem mass spectrometry

A procedure using gas chromatography and tandem mass spectrometry (GC-MS-MS) has been developed for the identification and quantification of some allelochemicals in wheat (Triticum aestivum L.). The quantities of allelochemicals in wheat shoots ranged from 2.9 to 110 mg per kilogram of dry shoot residues. Compared with gas chromatography-mass spectrometry (GC-MS), the GC-MS-MS technique significantly increased instrument selectivity and sensitivity, thereby providing more reliable quantitation results in the determination of the phytotoxic compounds examined during this allelopathy research.     

Global and selective detection of organohalogens in environmental samples by comprehensive two-dimensional gas chromatography-tandem mass spectrometry and high-resolution time-of-flight mass spectrometry

We successfully detected halogenated compounds from several kinds of environmental samples by using a comprehensive two-dimensional gas chromatograph coupled with a tandem mass spectrometer (GC×GC-MS/MS). For the global detection of organohalogens, fly ash sample extracts were directly measured without any cleanup process. The global and selective detection of halogenated compounds was achieved by neutral loss scans of chlorine, bromine and/or fluorine using an MS/MS. It was also possible to search for and identify compounds using two-dimensional mass chromatograms and mass profiles obtained from measurements of the same sample with a GC×GC-high resolution time-of-flight mass spectrometer (HRTofMS) under the same conditions as those used for the GC×GC-MS/MS. In this study, novel software tools were also developed to help find target (halogenated) compounds in the data provided by a GC×GC-HRTofMS. As a result, many dioxin and polychlorinated biphenyl congeners and many other halogenated compounds were found in fly ash extract and sediment samples. By extracting the desired information, which concerned organohalogens in this study, from huge quantities of data with the GC×GC-HRTofMS, we reveal the possibility of realizing the total global detection of compounds with one GC measurement of a sample without any pre-treatment.