静态顶空-气相色谱/质谱法同时检测环境水体中59种挥发性有机物

静态顶空法是一种简单、环保的样品前处理方法.通过对比试验,优化了影响静态顶空进样方法灵敏度的主要因素,确定了较佳的样品盐度(40%)、平衡温度(80℃)、平衡时间(10 min)、平衡压力(0.103 4 MPa)、定量环平衡时间(20 s)、进样时间(3 min)等前处理方法参数.采用优化后水样前处理条件及1.00 k V的检测器电压,59种挥发性有机物在特定的线性范围内,标准曲线线性相关系数均大于0.998,方法检出限为丙烯腈4.4μg/L、硝基苯7.6μg/L,其余挥发性有机物(VOCs)介于0.06~1.4μg/L,饮用水源水及污水处理厂进水实际样品加标回收率为60%~110%,精密度(RSD)为0.33%~22%(n=6).建立的静态顶空-气相色谱/质谱法(HS-GC/MS)水样前处理过程自动化,可同时对水中59种挥发性有机物进行检测.     

Volatile Profiles of Apricot Cultivars (Prunus armeniaca Lam.) Evaluated by Head Space Solid Phase Microextraction Gas Chromatography Mass Spectrometry

The volatile compounds of 85 regional apricot cultivars native to China were characterized by headspace-solid phase microextraction coupled with gas chromatography–mass spectrometry. A total of 156 volatile compounds were tentatively detected, 62 of which were identified in apricots for the first time. The composition and concentration of the volatile compounds varied greatly among the cultivars, with the number of individual compounds per cultivar ranging from 39 to 85, at concentrations of 9.0 to 296.5 mg/kg fresh weight. The apricots from northwest China had the highest concentrations of volatile compounds, while those from the southwest had the lowest concentrations. Based on principal component analysis, the cultivars were divided into four groups characterized by their volatile profiles: 1) terpenoids; 2) aldehydes; 3) terpenoids and aldehydes; and 4) an absence of characteristic volatiles. The greatest diversity of volatile compounds was found in cultivars from northwest China, while the diversity diminished progressively for the cultivars of north, northeast, and southwest China, indicating that the volatile profiles of the cultivars corresponded to their different ecogeographical groups.     

Characterization of the Volatile Compounds in Camellia oleifera Seed Oil from Different Geographic Origins

Volatile flavor of edible oils is an important quality index and factor affecting consumer choice. The purpose of this investigation was to characterize virgin Camellia oleifera seed oil (VCO) samples from different locations in southern China in terms of their volatile compounds to show the classification of VCO with respect to geography. Different samples from 20 producing VCO regions were collected in 2020 growing season, at almost the same maturity stage, and processed under the same conditions. Headspace solid-phase microextraction (HS-SPME) with a gas chromatography–mass spectrometer system (GC–MS) was used to analyze volatile compounds. A total of 348 volatiles were characterized, including aldehydes, ketones, alcohols, acids, esters, alkenes, alkanes, furans, phenols, and benzene; the relative contents ranged from 7.80–58.68%, 1.73–12.52%, 2.91–37.07%, 2.73–46.50%, 0.99–12.01%, 0.40–14.95%, 0.00–27.23%, 0.00–3.75%, 0.00–7.34%, and 0.00–1.55%, respectively. The VCO geographical origins with the largest number of volatile compounds was Xixiangtang of Guangxi (L17), and the least was Beireng of Hainan (L19). A total of 23 common and 98 unique volatile compounds were detected that reflected the basic and characteristic flavor of VCO, respectively. After PCA, heatmap and PLS-DA analysis, Longchuan of Guangdong (L8), Qingshanhu of Jiangxi (L16), and Panlong of Yunnan (L20) were in one group where the annual average temperatures are relatively low, where annual rainfalls are also low. Guangning of Guangdong (L6), Yunan of Guangdong (L7), Xingning of Guangdong (L9), Tianhe of Guangdong (L10), Xuwen of Guangdong (L11), and Xiuying of Hainan (L18) were in another group where the annual average temperatures are relatively high, and the altitudes are low. Hence, volatile compound distributions confirmed the differences among the VCO samples from these geographical areas, and the provenance difference evaluation can be carried out by flavor.     

Influence of Freezing and Different Drying Methods on Volatile Profiles of Strawberry and Analysis of Volatile Compounds of Strawberry Commercial Jams

Strawberry is the most consumed berry fruit worldwide due to its unique aroma and flavor. Drying fruits to produce a powder represents one of the possible conservation methods to extend their shelf-life. The aim of the present study was to compare the influence of freezing and different drying methods on the volatile profile of strawberry using the HS-SPME/GC–MS method, in addition to analysis of strawberry jam volatiles. A total of 165 compounds were identified, accounting for 85.03–96.88% of the total volatile compositions. Results and PCA showed that freezing and each drying process affected the volatile profile in a different way, and the most remarkable representative differential volatiles were ethyl hexanoate, hexyl acetate, (E)-2-hexenyl acetate, mesifurane, (E)-nerolidol, γ-decalactone, 1-hexanol, and acetoin. Shade air-dried, frozen, freeze-dried, and oven-dried 45 °C samples retained more of the fruity and sweet aromas of strawberry, representing more than 68% of the total aroma intensity according to the literature. In contrast, the microwave-drying method showed drastic loss of fruity esters. Strawberry jams demonstrated complete destruction of esters and alcohols in most jams, while terpenes were significantly increased. These findings help better understand the aroma of strawberry and provide a guide for the effects of drying, freezing, and jam processing.     

天然和人工培植红景天挥发油的对比研究

应用ＧＣ－ＭＳ和ＧＣ－ＩＲ两种联机法对比研究了天然和人工培植红景天挥发油、分别鉴定出２７个和２４个化合物。ＭＳ给出结构信息和ＩＲ给出官能团信息相结合，提高了分析测试复杂样品的可靠性。     

Microdistillation as a Useful Tool for the Analysis of Minute Amounts of Aromatic Plant Materials

The MicroDistiller (Eppendorf), enables the distillation of aromatic material even in very small quantities. Using the simple microdistillation technique, minute amounts ofCyclotrichium leucotrichum(Stapf ex Rech. fil.) Leblebici andC. stamineum(Boiss. and Hohen.) Manden. and Scheng. were investigated for their volatiles by GC/MS. The main constituents were identified as-caryophyllene (14%), camphor (12%), andp-menth-3-en-8-ol (11%) forC. leucotrichum, and pinocamphone (33%), isopinocamphone (13%), and myrtenyl acetate (9%) forC. stamineum.     

Effect of biotic and abiotic stresses on volatile emission of Achillea collina Becker ex Rchb

This study describes the application of headspace solid-phase microextraction (HS-SPME)–gas chromatography/mass spectrometry (GC/MS) to characterise the volatile fingerprint changes of Achillea collina, induced by aphids' infestation, mechanical damage and jasmonic acid (JA) treatment. The volatile organic compound profiles of A. collina, Prunus persica and Pisum sativum infested by Myzus persicae were also compared. Several changes were observed between control, infested, mechanically damaged and JA-treated plants, and new inducible volatile organic compounds (IVOCs) were emitted in response to biotic or abiotic stresses. Some of these were in common for all stresses and other compounds were in common only for two types of stress. Conversely some IVOCs were emitted only in response to the specific stimuli. The results suggested that there were species-specific and common IVOCs emitted by A. collina, P. persica and P. sativum in response to M. persicae infestation. In conclusion, HS-SPME–GC/MS seems to be a reliable analytical approach to study in vivo plant reaction to external stimuli.     

Chemical Approach to the Optimization of Conditions Using HS-SPME/GC–MS for Characterization of Volatile Compounds in Eugenia brasiliensis Fruit

Grumixama (Eugenia brasiliensis Lam.) is a native fruit of the Brazilian Atlantic Forest, belonging to the Myrtaceae family, which designatesthe most significant number of species with food potential. It stands out due to its phytochemical characteristics because of the presence of polyphenols and volatile organic compounds. Volatile compounds are substances released by foods that give off an aroma and influence flavor. Solid-phase microextraction is a technique that allows for low-cost, fast, and solvent-free extraction, has an affinity for numerous analytes, and is easily coupled to gas chromatography. The objectives of this work were to evaluate the efficiency of different fibers of SPME (solid-phase microextraction) in the extraction of volatile organic compounds from grumixama pulp; optimize a method for extraction time, temperature, and sample weight; and to determine the characteristic volatile profile of this fruit. For the extraction of volatile compounds, three fibers of different polarities were used: polar polyacrylate (PA) fibers, divinylbenzene/carboxyne/polydimethylsiloxane (DVB/CAR/PDMS) semipolar fibers, and polydimethylsiloxane/divinylbenzene (PDMS/DVB). Fourteen volatile organic compounds (VOCs) were identified by DVB/CAR/PDMS, six by PA, and seven by PDMS/DVB through solid-phase microextraction in the headspace mode (SPME-HS). Considering the total number of compounds identified, regardless of the fiber used, and the optimization of the method, Eugenia brasiliensis presented sesquiterpene fractions (85.7%, 83.3%, and 85.7% of total VOCs) higher than the monoterpene fractions (14.3%, 16.7%, and 14.3%) for DVB/CAR/PDMS, PA, and PDMS/DVB, respectively in its composition. In addition, it was possible to verify that the fiber DVB/CAR/PDMS presented a better efficiency due to the larger chromatographic area observed when the grumixama pulp was subjected to conditions of 75 °C, 2.0 g, and an adsorption time of 20 min.     

红景天挥发油的GC／MS／DS和GC／IR／DS研究

红景天挥发油的ＧＣ／ＭＳ／ＤＳ和ＧＣ／ＩＲ／ＤＳ研究阎吉昌，张宏徐少敏卫永弟，阎雪（东北师范大学测试中心，长春，１３００２４）（吉林省石油化工研究院，白求恩医科大学）关键词红景天，色谱／质谱，色谱／红外，复杂有机混合物应用色谱／质谱／计算机（ＧＣ／Ｍ...     

气相色谱法检测空气中有机物挥发总量的不确定度评定

对气相色谱法测定室内有机物挥发总量(TVOC)过程中可能引入的不确定度进行了分析和评定。通过实验数据计算得出室内空气中TVOC浓度的不确定度为:当取置信概率为95%,包含因子k=2,则其扩展不确定度Urel=13.73%。通过对不确定度的分析,指出在检测过程中质量控制的关键在于标准物质的浓度和气相色谱分析样品过程,该两项引入的不确定分量占总相对标准不确定度的93%,并提出了质量控制改进方法。     

吹洗和捕集色/质联机法定量分析水中挥发性有机物

本文详细地介绍了利用吹洗和捕集色/质联机法定量分析水中挥发性有机物的原理、过程和实验中应注意的问题。该方法在严格的质量保证和质量控制(QA/QC)下,定量分析水中挥发性有机物,得到了满意的结果。     

新型单壁碳纳米管采样吸附剂性能的评价

研究了单壁碳纳米管(SWCNTs)作为新型采样吸附剂的性能和效果,并应用于空气中挥发性有机化合物的分析测定。结果表明,单壁碳纳米管具有较大的比表面积,与经典Tenax TA吸附剂相比,对低碳数挥发性强的有机化合物回收率高,有更强的吸附能力;空白实验表明,SWCNTs易获得较低本底,具有化学惰性和疏水特性,采样时水的干扰小。当湿度增加时在误差允许的范围内准确度不受影响;实验测定具有较大的穿透容量和安全采样体积。将单壁碳纳米管吸附剂实际应用于大气中挥发性有机化合物的测定,通过与经典吸附剂Tenax TA相比,更适于采集大气中的挥发性有机化合物。     

顶空固相微萃取-气相色谱/质谱法分析鉴定畜禽粪便中的挥发性有机化合物

采用顶空固相微萃取(HS-SPME)-气相色谱/质谱法(GC/MS)测定了牛粪、猪粪以及鸡粪中的挥发性有机化合物(VOCs)。在优化HS-SPME条件的基础上,通过GC/MS分析,从牛粪中分离鉴定出44种VOCs,从猪粪中分离鉴定出40种VOCs,从鸡粪中分离鉴定出41种VOCs。HS-SPME-GC/MS具有简单、快速、无需有机溶剂等特点,适合于畜禽粪便中挥发性有机化合物的分析与鉴定。同时,该研究揭示了畜禽养殖场臭味物质的来源,为治理其环境污染提供了科学依据。     

Determination of volatile organic compounds in the dried leaves of Salvia species by solid-phase microextraction coupled to gas chromatography mass spectrometry

Salvia spp. are used throughout the world both for food and pharmaceutical purposes. In this study, a method involving headspace solid-phase microextraction combined with gas chromatography–mass spectrometry was developed, to establish the volatiles profile of dried leaves of four Iranian Salvia spp.: Salvia officinalis L., Salvia leriifolia Benth, Salvia macrosiphon Boiss. and two ecotypes of Salvia reuterana Boiss. A total of 95 volatiles were identified from the dried leaves of the five selected samples. Specifically, α-thujone was the main component of S. officinalis L. and S. macrosiphon Boiss. (34.40 and 17.84%, respectively) dried leaves, S. leriifolia Benth was dominated by β-pinene (27.03%), whereas α-terpinene was the major constituent of the two ecotypes of S. reuterana Boiss. (21.67 and 13.84%, respectively). These results suggested that the proposed method can be considered as a reliable technique for isolating volatiles from aromatic plants, and for plant differentiation based on the volatile metabolomic profile.     

Response surface optimisation applied to a headspace-solid phase microextraction-gas chromatography-mass spectrometry method for the analysis of volatile organic compounds in water matrices

A new method for the simultaneous determination of 12 volatile organic compounds (trans-1,2-dichloroethene, 1,1,1-trichloroethane, benzene, 1,2-dichloroethane, trichloroethene, toluene, 1,1,2-trichloroethane, tetrachloroethene, ethylbenzene, m-, p-, o-xylene) in water samples by headspace solid phase microextraction (HS–SPME)–gas chromatography mass spectrometry (GC–MS) was described, using a 100?µm PDMS (polydimethylsiloxane) coated fibre. The response surface methodology was used to optimise the effect of the extraction time and temperature, as well as the influence of the salt addition in the extraction process. Optimal conditions were extraction time and temperature of 30?min and ?20°C, respectively, and NaCl concentration of 4?mol?L^?1. The detection limits were in the range of 1.1?×?10^?3–2.3?µg?L^?1 for the 12 volatile organic compounds (VOCs). Global uncertainties were in the range of 4–68%, when concentrations decrease from 250?µg?L^?1 down to the limits of quantification. The method proved adequate to detect VOCs in six river samples.     

Optimization and Validation of HS-GC/MS Method for the Controlled Release Study of Microencapsulated Specific Bioattractants for Target-Plaguicide Production

Insect plagues are a problem often hard to solve due to the harmful effects caused by the pesticides used to combat them. Consequently, the pesticide market is increasingly trying to develop new technologies to prevent the unwanted effects that common plague treatments usually bring with them. In this work, four specific bioattractants of Musca domestica, extracted from fungi (β-ocimene, phenol, p-cresol, and indole) were microencapsulated with β-cyclodextrin in order to produce an economically and environmentally sustainable bait containing biocides in the near future. Cyclodextrins will retain these volatile compounds until their use by the consumer when the product comes into contact with water. Then, the bioattractants will be released in the medium in a controlled manner. An analytical methodology based on headspace extraction coupled to gas chromatography and mass spectrometry (HS-GC/MS) has been developed and validated following Environmental Protection Agency (EPA) and European Commission Directorate General for Health and Food Safety guidelines for the bioattractants controlled release study from the microencapsulated product. The analytical method has been shown to be accurate and precise and has the sensitivity required for controlled release studies of the four bioattractants analyzed. The release of the bioattractants from microencapsulated products achieved the “plateau” after 3 h in all cases.     

吸附—光催化联用去除室内挥发性有机物*

多孔吸附剂吸附和纳米TiO₂光催化是目前室内挥发性有机物（VOCs）去除所采用的主要手段。但存在吸附剂容量有限、饱和失效、TiO₂光催化剂活性低、失活和负载困难等问题。多孔吸附剂与纳米TiO₂联用,通过TiO₂光催化作用可实现吸附剂的原位再生,增加吸附剂的吸附容量;通过多孔吸附剂的吸附作用可为TiO₂光催化提供高浓度污染环境,提高催化剂活性,抑制催化剂失活,消除水蒸气分子对TiO₂表面活性吸附位的竞争吸附,解决催化剂分离难题;从而实现对室内VOCs污染的高效深度净化。本文对近年来多孔吸附剂与纳米TiO₂光催化联用去除室内VOCs进行了综合评述。介绍了吸附—光催化联用去除室内VOCs的多孔吸附剂类型,吸附/光催化复合材料的制备方法及常用反应器,分析了吸附—光催化联用去除室内VOCs过程中水蒸气、催化剂失活对光催化的影响等问题。     

Exploratory Study Using Urinary Volatile Organic Compounds for the Detection of Hepatocellular Carcinoma

Hepatocellular carcinoma (HCC) biomarkers are lacking in clinical practice. We therefore explored the pattern and composition of urinary volatile organic compounds (VOCs) in HCC patients. This was done in order to assess the feasibility of a potential non-invasive test for HCC, and to enhance our understanding of the disease. This pilot study recruited 58 participants, of whom 20 were HCC cases and 38 were non-HCC cases. The non-HCC cases included healthy individuals and patients with various stages of non-alcoholic fatty liver disease (NAFLD), including those with and without fibrosis. Urine was analysed using gas chromatography–ion mobility spectrometry (GC–IMS) and gas chromatography–time-of-flight mass spectrometry (GC–TOF-MS). GC–IMS was able to separate HCC from fibrotic cases with an area under the curve (AUC) of 0.97 (0.91–1.00), and from non-fibrotic cases with an AUC of 0.62 (0.48–0.76). For GC-TOF-MS, a subset of samples was analysed in which seven chemicals were identified and tentatively linked with HCC. These include 4-methyl-2,4-bis(p-hydroxyphenyl)pent-1-ene (2TMS derivative), 2-butanone, 2-hexanone, benzene, 1-ethyl-2-methyl-, 3-butene-1,2-diol, 1-(2-furanyl)-, bicyclo(4.1.0)heptane, 3,7,7-trimethyl-, [1S-(1a,3β,6a)]-, and sulpiride. Urinary VOC analysis using both GC–IMS and GC-TOF-MS proved to be a feasible method of identifying HCC cases, and was also able to enhance our understanding of HCC pathogenesis.     

纳米材料在用于癌症诊断的呼出气挥发性有机物检测中的应用

细胞新陈代谢的变化会导致挥发性有机化合物（VOCs）类型及含量发生变化,因此可通过分析某些标志性VOCs简立起多种疾病早期诊断的模型. 人体呼出物中特征VOCs的检测作为一种非侵入性、无损的检测手段,近些年在疾病检测领域已成为世界范围内的研究热点. 其中,纳米材料可用于增强传感器性能,并使传感器便携式小型化,推进检测传感器进入临床. 在这篇综述中,作者将种类繁多的传感器中用到的纳米材料归纳总结为金属、金属氧化物、碳基、复合物和MOFs基纳米材料等几类,并讨论了不同类纳米材料在VOCs检测中的优劣势. 本文所建立起的分析方法及讨论有助于进一步了解检测技术的优越性与局限性. 最后,作者对利用VOCs的检测实现癌症早期筛选的研究及发展提出了个人观点.