A PERSON PORTABLE FAST RESPONDING EXHALED BREATH ANALYZER

描述(由申请人提供) 拟议(在第一和第二阶段期间)开发一种便携式、高灵敏度和选择性、宽带实时数据采集、全球定位系统并可通过无线或互联网远程访问的个人“个人暴露监测仪”，用于检测人体呼气中存在的微量有害化学物质。该仪器将使用一种新的大气压“超音速脉冲离子束源(SPIBS)”，它是由该提议的主要研究人员最近开发的，以及一个小型聚焦飞行时间质谱仪(FTOF-MS)，该仪器过去也是由NASA的首席研究人员开发的(发表在NASA技术简报杂志上，2004年)。利用这种组合，将通过使用带电粒子计数技术来获得呼气的质谱图，该质谱图覆盖了当前感兴趣的所有化学品的整个质量范围，该技术能够在一个大的动态范围内允许灵敏地检测空气样品中的痕量物种，其中可能存在高浓度的其他化学物种。新颖之处在于，呼出的呼气将以短脉冲(~100ms)超音速光束的形式引入真空系统，其中包括微型FTOF-MS和带电粒子探测器，用于质量分析。这将减轻在常规使用的质谱仪中通常使用的真空泵的负荷，在该质谱仪中，要被质量分析的空气样本被连续引入。为了将空气样品不断地引入质谱仪的真空室，需要采用差动抽气方法的大型重型真空泵。这使得它们变得笨重、笨重和过度耗电。另一方面，脉冲导入减少了气体负荷，并允许使用最近上市的轻型微型真空泵，这些真空泵的运行需要低功率。这项提议的主要研究人员最近开发了一种真空系统，在该系统中，房间空气可以以持续约100ms的短脉冲的形式引入，而不会使真空室的压力增加到约10-6Torr。一个TOF可以在这个压力范围内工作，在这个短时间间隔内可以获得数千个TOF质谱图。这里提出的用于分析呼气的“个人暴露监测仪”将是个人携带的，可以放在背包里。它将具有以下新颖的特征：1)重量轻(估计小于3.6千克，包括微型阿尔卡特涡轮增压泵、隔膜泵和电子盒)，2)将由以皮带形式组装在一起的微型锂电池(该皮带的重量估计小于4千克)组成的24伏电源组供电，3)它将是低功耗(小于250瓦)，4)脉冲引入呼气以灵敏地检测(ppb范围)当前感兴趣的化学品，5)实时和快速的数据采集，6)无线数据传输，以及7)能够进行多个分析物测量或仅测量臭氧。这种仪器目前还不能在商业上进行任何比较。第一阶段的研发将利用我们的面包板仪器来证明脉冲引入从天然气公司获得的受污染空气的概念，测量其灵敏度和质量选择性。在第二阶段期间，将利用第一阶段的结果和有限的现场测试结果制造个人便携式仪器。

DESCRIPTION (provided by applicant) It is proposed to develop (during phase I and II) a person portable, highly sensitive and selective, broad band, real time data acquisition, GPS enabled and remotely accessible by wireless or by internet a "Personal Exposure Monitor" for the detection of trace amounts of harmful chemical species present in the exhaled breath of a human being. This instrument will employ a novel atmospheric pressure "supersonic pulsed ion beam source, (SPIBS)" recently developed by the principal investigator of this proposal and a miniature focusing time-of-flight mass spectrometer (FTOF-MS), also developed by the principal investigator for NASA in the past (published in the NASA Tech Brief Journal, 2004). Utilizing this combination, mass spectra of exhaled breath, covering the entire mass range of chemicals of present interest, will be obtained by employing the charged particle counting technique that is capable of a large dynamic range permitting sensitive detection of trace species in an air sample where other chemical species may be present in high concentrations. The novelty lies in the fact that the exhaled breath will be introduced into the vacuum system, housing the miniature FTOF-MS and the charged particle detector, in the form of short pulses (~ 100 ms duration) of supersonic beams for mass analysis. This will reduce the load on the vacuum pumps that are normally used in routinely employed mass spectrometers where the sample of air to be mass analyzed is introduced continuously. This continuous introduction of air sample into the vacuum chamber of a mass spectrometer requires large and heavy vacuum pumps employing differential pumping methods. This makes them heavy, bulky and excessively power consuming. On the other hand, pulsed introduction reduces the gas load and permits the use of recently available light weight miniature vacuum pumps requiring low power for their operation. The principal investigator of this proposal has recently developed a vacuum system in which the room air can be introduced in the form of short pulses lasting approximately 100 ms without increasing the vacuum chamber's pressure beyond about 10-6 Torr. A TOF can be operated in this pressure range and several thousands TOF mass spectra can be obtained in this short interval of time. The "personal Exposure Monitor" proposed here for the analysis of exhaled breath will be person portable and can be accommodated in a back pack. It will have the following novel features: 1) Light weight (estimated to be less than 3.6 kg which includes a miniature Alcatel turbo pump, a diaphragm pump and an electronics box), 2) will operate with power provided by a 24 volts power pack consisting of miniature Li batteries put together in the form of a belt (weight of this belt is estimated to be less than 4 Kg), 3) it will be low power consuming ( less than 250 watts), 4) pulsed introduction of the exhaled breath for sensitive detection (ppb range) of chemicals of present interest, 5) real time and fast data acquisition, 6) wireless data transmission, and 7) capable of multiple analyte measurement or the measurement of ozone alone. Such an instrument is not commercially available at the present time to make any comparison. The R & D during the Phase I will utilize our breadboard instrument to prove the concept of pulsed introduction of contaminated air procured from gas companies, measure its sensitivity, and mass selectivity. During Phase II a person portable instrument will be fabricated by utilizing the results of Phase I and limited field tested.