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《分析试验室》2016,(10)
为了实时、在线分析卷烟烟气,研制了一台采用真空紫外灯作电离源的光电离飞行时间质谱仪,主要由真空系统、进样接口、光电离室、离子传输区、反射式飞行时间质量分析器和数据采集系统等组成;采用甲苯标准气体对仪器的质量精度、分辨率、检出限和标准工作曲线等性能参数进行了测试;同时考察了该质谱仪在卷烟主流烟气气相化学成分分析中的应用。结果表明:质谱仪的质量精度优于1.0×10~(-4),分辨率优于2000,对甲苯的定性检出限为0.41 mg/m~3,标准工作曲线相关系数可达0.9990;质谱仪采用毛细管进样方式,能够直接与商用吸烟机联用,可实现在2 s内获得新鲜单口烟气气相化学成分的信息,非常适合对卷烟烟气进行实时、在线分析。 相似文献
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建立加热卷烟呼出烟气中苯酚的气相色谱质谱测定方法。采用真空辅助捕集装置对抽烟者呼出烟气进行捕集,用气相色谱质谱联用法对呼出烟气中苯酚进行定量分析。苯酚的质量浓度在0.004~0.50μg/mL的范围内线性关系良好,相关系数为0.999 5,检出限为0.000 8μg/mL,定量限为0.002 6μg/mL。测定结果的相对标准偏差为3.21%(n=6),加标回收率为81.8%~88.9%。在吸烟机上模拟抽烟者抽吸参数抽吸加热卷烟吸入烟气中苯酚的含量,并研究了苯酚的人体截留率。结果表明抽吸加热卷烟后,人体呼出烟气中苯酚的含量显著低于吸入加热卷烟烟气以及抽吸传统卷烟后呼出烟气中苯酚的含量,人体对苯酚的截留率为79.9%~97.8%,平均截留率为94.0%,与抽吸传统卷烟时人体对苯酚的截留率接近。 相似文献
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以自旋标记荧光探针4-((9-acridinecarbonyl)amino)-2,2,6,6-tetramethylpiperidin-1-oxyl(TEMPO-9-AC)研究了卷烟主流烟气中的碳中心自由基。以吸烟机抽吸卷烟,以弱荧光的TEMPO-9-AC作为捕集剂捕集卷烟主流烟气中的碳中心自由基,生成稳定的强荧光的碳中心自由基捕集加合物,以高效液相色谱-三重四极杆串联质谱联用仪(HPLC-MS/MS)对其结构进行了确认,并建立了高效液相色谱-荧光检测(HPLC-FLD)的定量方法。结果表明,方法的检出限为0.318 nmol/cig,相对标准偏差(RSD)为3.5%~9.7%;利用TEMPO-9-AC捕集体系鉴别出了10种碳中心自由基;对5种代表性卷烟烟气中的碳中心自由基进行了定量计算,获得了它们在主流烟气中碳中心自由基的含量数据,并发现碳中心自由基总量与焦油释放量之间具有高度的相关性。本法检出限低,重复性好,适用于卷烟主流烟气中碳中心自由基的结构验证及释放量的检测分析。 相似文献
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提出了气相色谱法测定卷烟烟气中涕灭威残留量的分析方法。通过吸烟机抽吸捕集卷烟主流烟气总粒相物和主流烟气气相物后经甲醇萃取,所得萃取液中涕灭威及其代谢物通过过氧化氢氧化转化为涕灭威砜,再用二氯甲烷提取除去干扰,然后采用DB-1701弹性石英毛细管柱分离,脉冲火焰光度检测器检测,外标法定量。方法的检出限(3S/N)为0.01μg·g~(-1),主流烟气总粒相物中涕灭威的回收率在99.0%~101.0%之间,相对标准偏差(n=6)为4.7%~10.2%;主流烟气气相物中涕灭威的回收率在97.7%~99.3%之间,相对标准偏差(n=6)为5.4%~9.6%。 相似文献
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建立了一种卷烟主流烟气中醛酮类香气化合物的超临界流体色谱/气相色谱-质谱测定方法。将捕集卷烟主流烟气粒相物的剑桥滤片用超临界流体萃取醛酮类香气成分后,通过配备高效分离柱的超临界流体色谱(SFC)先对香气成分进行划段,分离后的各段馏分再用GC-MS分析。结果表明:经SFC分离后的各段化合物之间基本不重叠,解决了GC-MS峰容量有限的问题,且分离出的醛酮类香气成分数量远多于直接进样分析法;样品直接进样后经GC-MS分析仅鉴定出29种醛酮类化合物,其中醛类7种、酮类22种;而经SFC分段后再用GC-MS分析,可鉴定出57种醛酮类化合物,包括13种醛类和44种酮类。3种不同焦油量卷烟主流烟气中醛酮类化合物种类和含量存在较大差异,每种卷烟主流烟气中分别含有不同特有醛酮类化合物。该研究为卷烟主流烟气中醛酮类香气成分的测定提供了新方法。 相似文献
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Zhang T Tang XN Lau KC Ng CY Nicolas C Peterka DS Ahmed M Morton ML Ruscic B Yang R Wei LX Huang CQ Yang B Wang J Sheng LS Zhang YW Qi F 《The Journal of chemical physics》2006,124(7):74302
We have developed an effusive laser photodissociation radical source, aiming for the production of vibrationally relaxed radicals. Employing this radical source, we have measured the vacuum ultraviolet (VUV) photoionization efficiency (PIE) spectrum of the propargyl radical (C(3)H(3)) formed by the 193 nm excimer laser photodissociation of propargyl chloride in the energy range of 8.5-9.9 eV using high-resolution (energy bandwidth = 1 meV) multibunch synchrotron radiation. The VUV-PIE spectrum of C(3)H(3) thus obtained is found to exhibit pronounced autoionization features, which are tentatively assigned as members of two vibrational progressions of C(3)H(3) in excited autoionizing Rydberg states. The ionization energy (IE = 8.674 +/- 0.001 eV) of C(3)H(3) determined by a small steplike feature resolved at the photoionization onset of the VUV-PIE spectrum is in excellent agreement with the IE value reported in a previous pulsed field ionization-photoelectron study. We have also calculated the Franck-Condon factors (FCFs) for the photoionization transitions C(3)H(3) (+)(X;nu(i),i = 1-12)<--C(3)H(3)(X). The comparison between the pattern of FCFs and the autoionization peaks resolved in the VUV-PIE spectrum of C(3)H(3) points to the conclusion that the resonance-enhanced autoionization mechanism is most likely responsible for the observation of pronounced autoionization features. We also present here the VUV-PIE spectra for the mass 39 ions observed in the VUV synchrotron-based photoionization mass spectrometric sampling of several premixed flames. The excellent agreement of the IE value and the pattern of autoionizing features of the VUV-PIE spectra observed in the photodissociation and flames studies has provided an unambiguous identification of the propargyl radical as an important intermediate in the premixed combustion flames. The discrepancy found between the PIE spectra obtained in flames and photodissociation at energies above the IE(C(3)H(3)) suggests that the PIE spectra obtained in flames might have contributions from the photoionization of vibrationally excited C(3)H(3) and/or the dissociative photoionization processes involving larger hydrocarbon species formed in flames. 相似文献
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Zheng Yang Taichang Zhang Yang Pan Xin Hong Zichao Tang Fei Qi 《Journal of the American Society for Mass Spectrometry》2009,20(3):430-434
For the comprehensive analysis of organic compounds, especially thermal labile and nonpolar compounds, an electrospray/vacuum
ultraviolet (VUV) single-photon ionization (ES-SPI) method was developed. The fine droplets of the sample solution from the
electrospray process were directed through a quartz capillary and two skimmers to form a molecular beam into a high vacuum
ionization chamber. The neutral sample molecules were softly ionized with tunable VUV light and analyzed with a reflection
time-of-flight mass spectrometer (RTOF-MS). The ionization energy (IE) and appearance onsets of fragments were obtained based
on the photoionization efficiency (PIE) spectrum. The isomers can also be distinguished. With this new method, clean (fragment-free)
mass spectra of nonpolar compounds, such as benzene, cyclohexane, and some thermal labile solid compounds (triphenylamine,
thioacetamide, and urea) have been obtained without any tedious pretreatment. The components of complex mixtures (gasoline
and kerosene) can be identified. Furthermore, quantitative analysis of the components can be obtained based on photoionization
cross section data. This method may be used for quantitative analysis of small biomolecules and natural products. 相似文献
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Peterka DS Kim JH Wang CC Poisson L Neumark DM 《The journal of physical chemistry. A》2007,111(31):7449-7459
The photoionization and photoelectron spectroscopy of pure He droplets were investigated at photon energies between 24.6 eV (the ionization energy of He) and 28.0 eV. Time-of-flight mass spectra and photoelectron images were obtained at a series of molecular beam source temperatures and pressures to assess the effect of droplet size on the photoionization dynamics. At source temperatures below 16 K, where there is significant production of clusters with more than 10(4) atoms, the photoelectron images are dominated by fast electrons produced via direct ionization, with a small contribution from very slow electrons with kinetic energies below 1 meV arising from an indirect mechanism. The fast photoelectrons from the droplets have as much as 0.5 eV more kinetic energy than those from atomic He at the same photon energy. This result is interpreted and simulated within the context of a "dimer model", in which one assumes vertical ionization from two nearest-neighbor He atoms to the attractive region of the He2+ potential energy curve. Possible mechanisms for the slow electrons, which were also seen at energies below IE(He), are discussed, including vibrational autoionizaton of Rydberg states comprising an electron weakly bound to the surface of a large HeN+ core. 相似文献
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By using a high-resolution infrared (IR) laser to prepare propyne (C(3)H(4)) in selected rotational levels of the excited nu(1) (acetylenic C-H stretching) vibration mode prior to vacuum ultraviolet (VUV) laser pulsed field ionization-photoelectron (PFI-PE) measurements, we have obtained rotationally resolved VUV-PFI-PE spectra for the C(3)H(4) (+)(X (2)E(32,12),nu(1) (+)=1) band. The analysis of these PFI-PE spectra leads to the determination of the spin-orbit constant of A=-13.0+/-0.2 cm(-1) for the C(3)H(4) (+)(X (2)E(32,12),nu(1) (+)=1) state. Using this A constant and the relative rotationally selected and resolved state-to-state photoionization cross sections thus measured, we have obtained an excellent simulation for the VUV-PFI-PE origin band of C(3)H(4) (+)(X (2)E(32,12)), yielding a value of 83 619.0+/-1.0 cm(-1) (10.367 44+/-0.000 12 eV) for the adiabatic ionization energy of C(3)H(4) [IE(C(3)H(4))]. The present two-color IR-VUV-PFI-PE study has also made possible the determination of the C-H stretching frequencies nu(1) (+)=3217.1+/-0.2 cm(-1) for C(3)H(4) (+)(X (2)E(32,12)). The spectral assignment and simulation were guided by high-level ab initio calculations on the IE(C(3)H(4)), Franck-Condon factors for photoionization transitions, and rotational constants and vibrational frequencies for C(3)H(4) (+). 相似文献
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WANG Jing WEI Li-xia YANG Bin YANG Rui HUANG Chao-qun SHAN Xiao-bin SHENG Liu-si ZHANG Yun-wu QI Fei YAO Chun-de LI Qi JI Qing . National Synchrotron Radiation Laboratory University of Science Technology of China Hefei P.R. China . State Key Laboratory of Engines Tianjin University Tianjin P.R. China 《高等学校化学研究》2006,22(3):375-378
Introduction Ashighlyreactivebuildingblocksandfundamen talreactionintermediatesinorganicsynthesis,thealkyl radicalfamilyplaysacentralroleinadiversearrayof importantprocessesrangingfromcombustion[1]toat mosphericchemistry[2].Amongalkylradicals,theeth ylrad… 相似文献
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Photoionization and dissociative photoionization characters of six quinones, including 1,2-naphthoquinone (1,2-NQ), 1,4-naphthoquinone (1,4-NQ), 9,10-phenanthroquinone (PQ), 9,10-anthraquinone (AQ), benz[a]- anthracene-7,12-dione (BAD) and 1,2-acenaphthylenedione (AND) have been studied with an infrared laser desorption/tunable synchrotron vacuum ultraviolet (VUV) photoionization mass spectrometry (IR LD/VUV PIMS) technique. Mass spectra of these compounds are obtained at different VUV photon energies. Consecutive losses of two carbon monoxide (CO) groups are found to be the main fragmentation pathways for all the quinones. Detailed dissociation processes are discussed with the help of ab initio B3LYP calculations. Ionization energies (IEs) of these quinones and appearance energies (AEs) of major fragments are obtained by measuring the photoionization efficiency (PIE) spectra. The experimental results are in good agreement with the theoretical data. 相似文献
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利用真空紫外同步辐射和反射式飞行时间质谱研究了乙苯分子的光电离, 通过测量母体分子的光电离质谱(PIMS)以及母体离子和主要碎片离子的光电离效率曲线(PIEs), 确定了乙苯分子的电离能IE(C8H+10)=(8.66±0.02) eV, 主要碎片离子C7H+7和C6H+6的出现能分别为(10.81±0.02)和(10.99±0.02) eV; 利用经验公式计算出产生碎片离子C7H+7和C6H+6需要的解离能(Ed)分别为(2.15±0.04)和(2.33±0.04) eV. 结合相关的热化学参数, 推算出C8H+10, C7H+7和C6H+6的标准生成焓分别为865.5, 927.2和1037.9 kJ/mol. 为进一步研究乙苯的大气光氧化反应机理提供了参考. 相似文献
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Summary 1. The dissociative processes observed in the photoionization of monoterpene alcohols have been investigated. It has been established that the relative intensities of the peaks of the heavy ions, including the molecular ions, are higher on photoionization than on electron impact.2. It has been found that the mass spectra of the isomeric alcohols obtained on photoionization differ from one another to a greater degree than the electronic mass spectra.Agrophysical Scientific-Research Institute. Translated from Khimiya Prirodnykh Soedinenii, No. 6, pp. 723–726, November–December, 1974. 相似文献
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对硝基甲苯的同步辐射光电离研究 总被引:2,自引:0,他引:2
光电离对硝基甲苯(PNT)可获得其电离势及碎片离子的出现势,并由此推断出离子产生的可能通道.目前尚未见到有关PNT光电离研究的报道,仅George等[‘j使用电子轰击电离质谱测得过它的电离势.我们使用同步辐射光电离质谱测得了PNT的电离势和8种碎片离子的出现势,给出了飞行时间(TOF)质谱图,归属了质谱中的主要离子峰,初步分析了光解离电离通道.1实验部分实验装置由阈值光电子一光离子符合(TPEPICO)装置改造而成[’,’],光电离室上方的四极质谱计由TOF质谱计代替,下方的四极质谱计由盛固体样品的小炉取代.样品蒸… 相似文献