质子转移反应质谱对肺癌患者呼气中特征性VOCs的筛选及研究

利用质子转移反应质谱(PTR-MS)对40名肺癌患者、32名健康志愿者呼出气体中的挥发性有机物(VOCs)进行检测,Mann-Whitney秩和检验与多因素logistic回归的结果表明,呼气中VOC 33、VOC 39、VOC 45可能为肺癌人群的呼气标志物,同时VOC 45在小细胞肺癌和非小细胞肺癌患者之间存在显著差异。以肺癌人群的呼气标志物作为自变量,采用二元logistic回归分析和Fisher判别分析分别建立肺癌预测模型。logistic回归模型的受试者工作曲线下面积(AUC)达到0.878,灵敏度和特异性分别为85.5%和63.5%。Fisher判别模型的受试者工作曲线下面积(AUC)达到0.822,灵敏度和特异性分别为82.5%和62.5%。两种模型对肺癌的预测均具有统计学意义。     

人体呼出挥发性有机物的口罩微萃取气相色谱-质谱分析

人体呼气中含有大量与人类行为和健康状况有关的挥发性有机物(VOCs).本研究采用口罩微萃取方法富集人体呼出VOCs,并联用3种气相色谱-质谱仪(GC-MS)对呼出VOCs进行分析鉴定与比对.优化了固相微萃取探针及富集采样时间;通过对比正常生理呼出VOCs和口罩的背景信号,探索了人体经过不同的食物摄入和口腔护理对呼出VO...     

Proton Trasfer Reaction Mass Spectrometry for On-line Detection of Trace Volatile Organic Compounds in Breath

通过对自主研制的大气成分在线检测质子转移反应质谱的进样管路系统进行改造,建立了可在线检测呼气中痕量挥发性有机物的质子转移反应质谱装置.通过对呼气进样系统的旁路流量控制,实现对进样速度的调控,既可提高进样速度,以满足实时监测呼气中指定成分浓度变化;也可适时关闭旁路,以降低进样速度,从而对呼气成分进行全谱分析,避免采样袋采样和浓缩的复杂程序和潜在干扰.以作者呼出气体作为研究对象,对装置性能进行测试,结果表明:装置最快响应时间可达1 s,对呼气中丙酮的探测灵敏度高达每10-9(V/V)浓度的信号强度为14.6 counts/s,多次呼气测量重复性好,有望广泛应用于呼气疾病诊断研究.     

质子转移反应质谱的建立与性能研究

报道了自行研制的质子转移反应质谱的基本结构和性能。利用水蒸气辉光放电产生了反应离子H3O ,以合成空气为反应气体,测量了H3O 与合成空气中的水反应产生的团簇离子H3O (H2O)n的质谱。实验发现,当漂移管电场与分子密度比值为144Td时,增加的离子能量可以阻止团簇离子H3O (H2O)n的形成,质谱观察到的离子主要是H3O ,其纯度可达99%以上,这时H3O 与有机物分子如甲苯的质子转移反应的产物离子也呈单一形式,团簇离子得到很好地抑制。根据离子强度和离子反应时间等参数,获得了PTR-MS目前的检出限为10-8(V/V)。利用PTR-MS对标准浓度甲苯及其稀释气体进行检测,表明PTR-MS在线定量检测准确性良好,线性动态范围跨越3个数量级,能够应用于大气中痕量挥发性有机物的实时在线测量。     

质子转移反应-飞行时间质谱检测呼出气体中痕量挥发性有机物

通过对自主研制的质子转移反应飞行时间质谱(PTR-TOF-MS)进样口的改造,实现了对呼出气体的实时、在线定量检测,并对23名志愿者(11名男性健康受试者、11名女性健康受试者和1名胃病患者)的呼出气体进行28天的实时在线监测。结果表明,健康人群呼出气体中主要的挥发性有机物(VOCs)为甲醛、丙烯、乙醛、丙酮、异丙醇和异戊二烯等,浓度基本服从对数正态分布,且甲醛、丙烯、异丙醇主要集中在40~100 ppb浓度范围内,乙醛的浓度主要集中在80~180 ppb浓度范围内,丙酮主要集中在500~1500 ppb浓度范围内,异戊二烯主要集中在8~20 ppb的浓度范围内;呼出气体浓度在性别上也存在差异,其中,受试人群中男性呼出气体中丙酮的浓度高于女性,而乙醛和异丙醇浓度低于女性。胃病患者的呼出气体中甲醛和丙酮含量明显高于健康人群;乙醇和乙醛是饮酒者呼出气体的主要标志物,乙醛是乙醇的代谢产物,随着乙醇浓度的变化而变化。     

呼气中痕量挥发性有机物的质子转移反应质谱在线检测研究

通过对自主研制的大气成分在线检测质子转移反应质谱的进样管路系统进行改造,建立了可在线检测呼气中痕量挥发性有机物的质子转移反应质谱装置。通过对呼气进样系统的旁路流量控制,实现对进样速度的调控,既可提高进样速度,以满足实时监测呼气中指定成分浓度变化;也可适时关闭旁路,以降低进样速度,从而对呼气成分进行全谱分析,避免采样袋采样和浓缩的复杂程序和潜在干扰。以作者呼出气体作为研究对象,对装置性能进行测试,结果表明:装置最快响应时间可达1s,对呼气中丙酮的探测灵敏度高达每10-9(V/V)浓度的信号强度为14.6counts/s,多次呼气测量重复性好,有望广泛应用于呼气疾病诊断研究。     

柔性PDA薄膜阵列用于双模光学检测VOC标志物气体

本研究以亲油性的双面胶作为基底,利用滴涂二乙炔单体结合紫外光聚合来制备均匀的聚二乙炔(PDA)薄膜,通过荧光和颜色两种信号变化模式(即"双模光学检测")研究了PDA薄膜对VOC气体的响应性,发现制备的PDA薄膜在2 min内就可以实现明显的荧光和颜色变化,有效解决了目前PDA薄膜在VOC气体检测方面存在响应速度慢、薄膜均一性差等问题.此外,为解决单一PDA薄膜的交叉响应性问题,本研究制备了四种不同的基于双面胶基底的PDA薄膜,并将制备的4种PDA薄膜集成到一片PDMS薄膜基底上来构建柔性的传感阵列,利用阵列的颜色变化结合模式识别技术,实现了对8种VOC气体的快速、灵敏区分.进一步将制备的PDA薄膜阵列用于健康人、模拟糖尿病及肾病患者呼出气体中VOC标志物的辨别和分析研究,发现可以将三类人的呼出气体清晰地区分,说明了该阵列在呼气疾病诊断中的应用前景.与目前报道的PDA薄膜阵列相比,本研究中基于双面胶基底的PDA薄膜阵列具有气体响应速度快、灵敏性高、柔韧性好、制备工艺简单、成本低、易于大规模制备等优点,有望用于实VOC气体检测研究中.     

质子转移反应质谱用于痕量挥发性有机化合物的在线分析

质子转移反应质谱(PTR-MS)是一种化学电离源质谱技术,专门用于痕量挥发性有机化合物(VOCs)实时在线检测.此技术利用H3O-作化学电离源试剂离子与作为质子接受体的VOCs发生质子转移反应.大气中的O2,N1,CO2等主要成分由于其质子亲和势低于H2O,而不与H3O发生质子转移反应,因此可在大气环境下检测痕量VOC...     

多反应离子的质子转移反应质谱

在无放射性辉光放电离子源内, 采用不同试剂气体进行放电, 为质子转移反应质谱(PTR-MS)新增了强度在10⁵ cps量级的3种反应离子NH₄⁺, NO⁺和O₂⁺, 纯度大于95%; 测试了这3种反应离子的离子-分子反应特征. 采用H₃O⁺, NH₄⁺, NO⁺和O₂⁺等4种反应离子对同分异构体丙醛/丙酮进行检测发现, H₃O⁺和NH₄⁺均不能区分的丙醛/丙酮可采用NO⁺或O₂⁺进行区分. 结果表明, 增加反应离子不仅使PTR-MS的可检测有机物范围不再局限于质子亲和势(PA)大于H₂O的有机物, 还提高了PTR-MS区分同分异构体的能力.     

高血糖人群呼气标志物的质子转移反应质谱研究

利用自制的质子转移反应质谱(PTR-MS)探索了高血糖人群呼气特征挥发性有机物(VOCs),利用改进的呼气分析系统对70名血糖含量正常志愿者与22名高血糖志愿者的呼气进行实时在线分析,数据统计分析采用Mann-Whitney U非参数检验和线性判别分析法。实验结果表明两组受试者呼气存在5种差异VOCs,该5种VOCs的质荷比(m/z)分别为61、31、120、104、82。其线性判别模型的受试者工作曲线(Re-ceiver operating curve,ROC)下面积达到0.926,灵敏度和特异度分别为86.4%和84.3%,该模型有一定的诊断价值。考察了两组志愿者呼气中丙酮含量的分布情况,统计分析结果显示两组的丙酮含量无显著性差异,丙酮含量与血糖浓度间也无显著相关性。     

乙酸乙酯在Al2O3-Ce0.5Zr0.5O2负载的金属氧化物催化剂上的催化燃烧

制备了Fe, Co, Cu, Cr和Mn金属氧化物催化剂, 所用载体为Al2O3-Ce0.5Zr0.5O2复合氧化物. 利用X射线衍射(XRD), 程序升温还原(TPR), 储氧量测试, BET比表面测试和光电子能谱(XPS)表征了催化剂. 并利用活性测试表征了各种催化剂对乙酸乙酯催化燃烧能力. 各种表征结果证实, 由于催化剂Mn/Al2O3-Ce0.5Zr0.5O2(1:2, 质量比)具有最多的可还原物种, Cu/Al2O3-Ce0.5Zr0.5O2(1:2)具有较多的可还原物种和最强的可还原能力, 使它们对乙酸乙酯催化燃烧表现出了最好的活性. 在催化剂Cu/Al2O3-Ce0.5Zr0.5O2(1:2)和Mn/Al2O3-Ce0.5Zr0.5O2(1:2)上, 乙酸乙酯于245 ℃转化了99%, 表明这两种催化剂具有广泛的应用潜力.     

Catalytic Combustion of Ethyl Acetate over Al2O3- Ce0.5Zr0.5O2 Supported Metal Oxide Catalysts

The catalysts for the combustion of ethyl acetate were prepared using Fe, Co, Cu, Cr, and Mn metal oxide as active components supported on Al₂O₃-Ce_0.5Zr_0.5O₂ mixed oxides and characterized by X-ray diffraction (XRD), temperature programmed reduction (TPR), oxygen storage capacity measurement, BET surface area, XPS measurement, and activity test. According to the results of characterization, it was found that Cu/Al₂O₃-Ce_0.5Zr_0.5O₂ (1:2, mass ratio) and Mn/Al₂O₃-Ce_0.5Zr_0.5O₂ (1:2) catalysts presented excellent activity for the catalytic combustion of ethyl acetate, because of the more reducible species and high reducibility of the catalysts. For ethyl acetate oxidation, more than 99% conversion was achieved at 245 °C over catalysts Cu/Al₂O₃-Ce_0.5Zr_0.5O₂ (1:2) and Mn/Al₂O₃-Ce_0.5Zr_0.5O₂ (1:2, mass ratio), indicating that the catalysts had great potential for wide use.     

Detection of volatile organic compounds using surface enhanced Raman spectroscopy substrates mounted on a thermoelectric cooler

Preliminary results for a volatile organic compound (VOC) sensor based on surface enhanced Raman spectroscopy (SERS) are described. The sensor is comprised of a SERS substrate mounted on a thermoelectric cooler (TEC). The SERS substrate is chemically modified with a thiol coating that prevents oxidation of the roughened silver surface and attracts the analyte of interest to the SERS surface. Using this sensor, detection of chlorinated solvents, aromatic compounds, and methyl t-butyl ether (MTBE) is demonstrated.     

Recent Advances of Beta Zeolite in the Volatile Organic Compounds(VOCs) Elimination by the Catalytic Oxidations

Volatile organic compounds(VOCs) have become one of the most serious threats to human health and eco-environment due to their volatility, toxicity and diffusivity, etc. Catalytic completely oxidation had been regarded as a highly efficient strategy for the VOCs abatement. Metal or metal oxides supported on zeolite have been considered as superior catalysts for the treatment of VOCs. Among them, Beta zeolites have attracted many attentions due to their unique structure and consequently catalytic properties in the oxidation of VOCs. The progresses and developments made in the understanding and design of Beta zeolites-based catalysts in the completely oxidation of VOCs in the past two decades have been systematically summarized in this review.     

23种挥发性有机化合物在3种吸附剂上漏出容量的测定评价

采用吸附热解吸－气相色谱－质谱法对23种挥发性有机化合物Chromosorb 106、Tenax TA、Tenax TG等3种吸附剂上漏出容量进行了测定。根据实验结果确定了不同的化合物应选择不同的吸附剂及相应的采样体积。结果表明,Chromosorb 106可较好地吸附低沸点的挥发性有机化合物,Tenax TA、Tenax TG均可用于沸点较高的挥发笥有机化合物吸附,这对测定大气中的有机化合物含量采样有一定的参考价值。     

Cyclodextrin Polymer Films Optical Waveguide Sensor for Volatile Organic Gas Detection

A sensitive optical waveguide(OWG) sensor which can be used to detect volatile organic compounds(VOCs) was presented. The sensing device(element) was fabricated by means of the immobilization of polyvinyl pyrrolidone(PVP)-cyclodextrin(CD) composite film over a single-mode potassium ion exchanged glass OWG via spin-coating method. The sensor shows higher response to styrene gas than to other VOCs and displays a linear response to styrene gas in a range of 1-1000 μL/L.     

地下水中挥发性有机物结构与色谱保留关系研究

本文采用分子电性距离矢量( Molecular Electronegativity-distancevector,MEDV)对地下水中26个挥发性化合物进行了结构表征,并与其色谱保留时间建立定量结构-保留关系(QSRR)模型.得到的MLR模型复相关系数(R2)为0.901,留一法(LOO)交互校验(CV)预测值的复相关系数(R2cv)为0.806;PLSR模型复相关系数(R2)为0.882,留一法(LOO)交互校验(CV)预测值的复相关系数(R2cv)为0.750.结果表明分子电性距离矢量(MEDV)能较好地表征该体系化合物结构,所建模型具有良好的稳定性与预测能力.     

Low-temperature plasma ionization source for the online detection of indoor volatile organic compounds

A simple-structure, low-power, and low-cost low temperature plasma (LTP) ionization source, coupled with mass spectrometry, for the online detection of indoor volatile organic compounds (VOCs) has been constructed in this work. Air, instead of noble gases, was employed as the discharging and carrier gas. And a custom-built AC high-voltage power supply with a total power consumption of 5 W, frequency of 2-4 kHz, and amplitude around 1-5 kV_p-p was used. This LTP source is a soft ionization source. The initial performance of the ionization source has been evaluated by ionizing samples including alcohols, ketones, aldehydes and aromatics. These compounds cover most of the common air pollutants concerning people's health. It is well known that those plasmas generated by dielectric barrier discharge (DBD) produce significant amount of metastable species and electrons with mean energies greater than several electronvolt, but minimal fragmentation was observed in our work. Protonated ions are the dominant product for the VOCs detected after the ionization process. Further work has been conducted to confirm the detection feature of this source. The results are promising enough to ensure the novel LTP ionization source as an effective tool for the online detection of indoor VOCs.     

二氧化铈-铈掺杂锰氧化物纳米复合物高效紫外-可见-红外光热催化净化乙酸乙酯

乙酸乙酯是一种重要的有机溶剂,广泛应用于涂料、粘合剂和塑料及石化等工业生产,但作为一种主要的挥发性有机污染物(VOCs),其对大气环境造成严重污染.目前工业上主要采用负载型贵金属催化剂催化燃烧的方法进行净化处理,但该方法存在催化剂价格昂贵和能耗高的问题,迫切需要开发活性高、稳定性好、成本低及能耗小的催化新方法和新材料....     

Discrimination of Lung Cancer Related Volatile Organic Compounds with a Colorimetric Sensor Array

A simple and rapid discrimination of four lung cancer related volatile organic compounds (VOCs) was achieved with a novel colorimetric sensor array. Based on the cross-responsive mechanism, the sensor system exhibited high sensitivity to selected lung cancer biomarkers, including p-xylene, styrene, isoprene, and hexanal with concentrations varying from 50 ppb to 500 ppb. By extracting color information, it provided good selectivity and fine discrimination of selected gases via pattern recognition with Fisher linear discriminant (FLD). Additionally, with the employment of the Takagi-Sogeno Fuzzy Neural Network (TSFNN), different concentrations of selected VOCs were discriminated. It also suggested that the colorimetric sensor array proposed could not only distinguish different lung cancer related VOCs but also discriminate specific VOCs of different concentrations with an average rate of classification up to 95%. Our preliminary study demonstrated that the cross-responsive sensor array had infinite potential for further clinical and commercial use for early diagnosis of lung cancer.