"Airborne Deployment of the Aerosol Mass Spectrometer during the ACE-Asia Field Campaign"
Jose Jimenez, Roya Bahreini, Richard Flagan, John H. Seinfeld (California Institute of Technology); Haflidi Jonnson (Naval Postgraduate School); John Jayne, Douglas Worsnop (Aerodyne Research)

The Aerosol Mass Spectrometer (AMS) has been recently developed to provide real-time quantitative measurement of aerosol size and chemical composition over the 50 nm to 5 micron diameter size range. The AMS was deployed inside the CIRPAS Twin Otter airplane during the ACE-Asia field campaign. This was the first aircraft deployment for this type of mass spectrometer. The AMS operated unattended, and collected data successfully during most Twin Otter flights (15 out of 19). The main challenges encountered in this deployement and the strategies used or planned to overcome them will be described. The ACE-Asia field experiment was designed to characterize how particles emitted in eastern Asia (China, Korea, and Japan) affect climate through both direct and indirect radiative forcing. The submicron aerosol was present in discrete layers about 0.5-1 km deep, separated by layers with much lower aerosol mass concentration. Sulfate was a major aerosol component during all flights, and its size distribution was remarkably constant days and atmospheric layers. Ammonium, nitrate, and organics were also observed in the aerosol.
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"Microfabrication of Cylindrical Ion Trap Mass Spectrometer Arrays"
Tim Short, David Fries, Gottfried P. G. Kibelka (Center for Ocean Technology, University of South Florida); Himani Peddanenikalva, Shekhar Bhansali (Dept. of Electrical Engineering, University of South Florida)

Recent interest in cylindrical ion trap (CIT) mass spectrometers [1-3] stems primarily from the ease with which the cylindrical geometry can be miniaturized and fabricated as compared to the hyperbolic surfaces found in conventional quadrupole ion trap mass spectrometers. Since the rf voltage needed to eject a given mass/charge ion scales as the square of the ion trap radius, a decrease in ion trap dimensions provides a significant reduction in electronics requirements, thereby providing a pathway for overall system miniaturization. A drawback of ion trap miniaturization, however, is a severe reduction in sensitivity due to decreased ion storage capacity. Higher ion capacity can be achieved by assembling an array of identically sized CITs, thus improving overall sensitivity [4]. Key factors in optimizing the performance of CIT arrays are the uniformity of CIT dimensions (e.g., hole size and shape) and flatness of endplates and transmission grids (if used). Microfabrication techniques can be used to provide excellent uniformity of holes and structures through, e.g., photolithography techniques and batch fabrication processes, leading to the possibility of low-cost high-performance CIT-array devices. We will present progress in the design, fabrication and testing of CIT arrays using two separate microfabrication approaches. One approach involves deep reactive ion etching (DRIE) of silicon to form arrays of "ring electrode" holes and endplate structures. These structures will be metallized to create conducting surfaces and then bonded, with insulating layers between them, to form monolithic CIT array devices. A separate approach uses micro-electric discharge machining (micro-EDM) of metal plates to form the "ring electrode" and endplate structures, and subsequent bonding with insulating layers to form the CIT arrays. A key feature in both designs will be use of microfabricated endplates that provide high transmission rigid grid-structures for each CIT of the array. This construction should optimize electron and ion transmission into and out of the CIT, while providing high-quality electric field definition within each CIT.
References: 1. J. Mitchell Wells, Ethan R. Badman, and R. Graham Cooks, Analytical Chemistry, Vol. 70, No. 3, pp. 438-444, 1998. 2. Oleg Kornienko, Peter T. A. Reilly, William B. Whitten, and J. Michael Ramsey, Review of Scientific Instruments, Vol. 70, No. 10, pp. 3907-3909, 1999. 3. Ethan R. Badman, Rudolph C. Johnson, Wolfgang R. Plass, and R. Graham Cooks, Analytical Chemistry, Vol. 70, No. 23, pp. 4896-4901, 1998. 4. Ethan R. Badman and R. Graham Cooks, Analytical Chemistry, Vol 72, No. 14, pp. 3291-3297, 2000. Financial support for this project was provided by the U.S. Army, Space and Missile Defense Command to the University of South Florida through grant DASG60-00-C-0089.
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"Adaptation of a commercially available RGA for use onboard the ISS"
Norbert Mueller, Roman Sonderegger, Daniel Vogel (Inficon AG, Liechtenstein); Carlos Pereira (HTS AG, Switzerland)

A residual gas analyzer (RGA) was developed for the Material Science Laboratory - Vacuum Gas System (MSL-VGS) onboard the ISS to determine krypton leakage in sealed cartridges before and during vacuum metallurgy experiments. Krypton leakage is an indication of rupture of the cartridges which may contain dangerous chemicals such as arsenic and thus the RGA is a central safety component of the metal processing facility. The RGA also allows composition analysis of off-gases and by products prior to release to the ISS vacuum lines. A commercially available RGA (PRISMA QMS 200) was selected and adapted as it offers several advantages as e.g.: a) Due to the large number of systems manufactured already (several thousands), all problems that may show up with more prototype like systems have been overcome already, b) based on a standard system, the instrument could be developed at a reasonable price, c) the instrument had flown on a previous shuttle mission and several parabolic flights. The adaptations of the standard parts for use in space included special fixation of all mechanical and bigger electronics parts to withstand the enormous forces during launch on board the space shuttle, replacement of flammable and dangerous components and special coating of all electronics boards. For mounting, transportation, dust tightness, depressurization and heat management a special housing was designed. Flight and test systems are completed and final tests have been performed so that the units can be transported to and installed in the International Space Station. The design of the instrument as well as all necessary adaptations and the results of performance tests will be presented.
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"Miniaturized GC/MS Instrumentation: MEMS-based Gas Chromatography Coupled with Miniature Quadrupole Array and Paul Ion Trap Mass Spectrometers"
Paul M. Holland, Ara Chutjian, Murray Darrach, Otto Orient (Jet Propulsion Laboratory)

Miniaturized chemical instrumentation is needed for in situ measurements in planetary exploration, spaceflight applications, and other extreme environments. Here, factors such as small size and enhanced robustness are important. In response to this need, we are developing miniaturized GC/MS instrumentation which combines chemical separations by gas chromatography (GC) with mass spectrometry (MS) to provide positive identification of chemical compounds in complex mixtures of gases, such as those found in the International Space Station's cabin atmosphere. Our designs utilize MEMS-based micro gas chromatography components coupled with either a miniature quadrupole mass spectrometer array (QMSA) or compact, high-resolution Paul ion trap. Key design issues include high sensitivity, good MS resolution (0.5 amu FWHM or better), low power, robustness, low GC flow rates to minimize vacuum-pumping requirements, and the use of a modular approach to adapt to different environments. Among the potential applications for such instrumentation are in situ detection of astrobiology signatures (using air sampling or ground-drilling techniques), planetary aeronomy, and monitoring of cabin air during long duration human flight. This work has been carried out in part at the Jet Propulsion Laboratory, California Institute of Technology, and was supported by the National Aeronautics and Space Administration.
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"Dual Source Time-of-Flight Mass Spectrometer and Sample Handling System"
William B. Brinckerhoff, Timothy J. Cornish, Johns Hopkins University/Applied Physics Laboratory); P. R. Mahaffy (NASA/Goddard Space Flight Center)

We present details of an instrument under development for potential NASA missions to planets and small bodies. The instrument comprises a dual ionization source (laser and electron impact) time-of-flight mass spectrometer (TOF-MS) and a carousel sample handling system for in situ analysis of solid materials acquired by, e.g., a coring drill. This "DS-TOF" instrument could be deployed on a fixed lander or a rover, and has an open design that would accommodate measurements by additional instruments. The sample handling system (SHS) is based on a multi-well carousel, originally designed for a comet mission. Solid samples, in the form of drill cores or as loose rock chips or fines, are inserted into the SHS through an access port, sealed in vacuum, and transported around the carousel to a pyrolysis cell and/or directly to the TOF-MS inlet. Samples at the TOF-MS inlet are xy-addressable for laser or optical microprobe. Cups may be ejected from their holders for analyzing multiple samples or caching them for return. Samples are analyzed with laser desorption and evolved-gas/electron-impact sources. The dual ion source permits broad studies of elemental, isotopic, and molecular composition of unprepared samples with a single mass spectrometer. Pulsed laser desorption permits the measurement of abundance and isotope ratios of refractory elements, as well as the detection of high-mass organic molecules in solid samples. Evolved gas analysis permits similar measurements of the more volatile species in solids and aerosols. The TOF-MS is based on previous miniature prototypes at JHU/APL that feature high sensitivity and a wide mass range. The laser mode, in which the sample cup is directly below the TOF-MS inlet, permits both ablation and desorption measurements, to cover elemental and molecular species, respectively. In the evolved gas mode, sample cups are raised into a small pyrolysis cell and heated, producing a neutral gas that is electron ionized and pulsed into the TOF-MS. (Any imaging and laser microprobe studies would necessarily precede the pyrolysis step to assure that the grain-scale composition is captured.) Details will be given on the DS-TOF operating modes envisioned for various in situ measurement objectives on asteroid and Mars missions. Initial results from the laboratory breadboard effort, including recent analyses of various calibration samples, SHS sealing mechanisms, and vacuum system requirements (for Mars) will be presented. The authors acknowledge the contributions of A. Cheng, H. Niemann, D. Harpold, D. Yucht, S. Rafeek, S. Gorevan, S. Ecelberger, T. McCoy, E. Vicenzi, and G. Managadze. Support is provided by NASA Grant NAG5-10693.
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"Real Time Volcanic Gas Monitoring Station using "In-Situ" Mass Spectrometry at Irazu Volcano"
Jorge A. Diaz (Universidad de Costa Rica); W. Ronald Gentry, Clayton F. Giese (University of Minnesota); Eduardo Malavassi, Erick Fernandez, Eliecer Duarte [Observatorio Vulcanologico y Sismologico de Costa Rica (OVSICORI)]; Juan Valdez [Laboratorio de Quimica de la Atmosfera (LAQAT), Universidad Nacional]

Following the research on volcanic monitoring using field-portable mass spectrometers presented last year's at the HEMS 2001 workshop , we describe the operation of the first real time MS based gas monitoring station in Costa Rica. The station is located at Irazu volcano ans is the first step of an attempt to establish a network of mass spectrometers designed to provide reliable and continuos information on the gas geochemistry of the volcanoes and its role to forecast volcanic eruptions . The systems used are described together with the first data collected.
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"Ion Trap Secondary Ion Mass Spectrometry - Moving Toward Fieldable Systems"
Anthony D. Appelhans, J. E. Olson [Idaho National Engineering and Environmental Laboratory (INEEL)]

In the event that chemical weapons are released somewhere in an urban area of the United States how will it be determined that the area is decontaminated to the point it can be opened to the public? Chemical weapons in an urban environment present unique challenges to decontamination and characterization because once released they are partitioned between different physical and chemical states, which dictate their mobility, toxicity, and susceptibility to treatment. CW's in the vapor state can be readily dispersed to non-toxic concentrations, are highly susceptible to environmental degradation, and the technologies for detecting them in the gas phase are relatively mature. However, adsorption on solid surfaces presents a difficult challenge for both detection and decontamination, because many CW's can bind tightly to a surface, resisting extraction or degradation, and can change form into equally toxic compounds while on the surface, confounding detection technologies tuned only to the agent compound. So, once the air has cleared, and the volatile components have dispersed, how is it determined if there remain on the surface, the steps, the handrails, the benches, a tightly bound concentration of agent, or equally toxic byproducts of the environmental or intentional degradation of the agent. Ion trap secondary ion mass spectrometry (ITSIMS) has been applied for detecting and characterizing trace levels of a variety of complex compounds on surfaces. In most cases the goal is simple detection and chemical identification. Past experience has demonstrated that levels down to 0.001 monolayer can be detected on many type of environmental samples such a soil, leaves, minerals, and concrete . In previous studies involving the detection of the nerve agent VX on different substrates it was noted that the degradation of the VX was highly dependent upon the substrate. For sandy soils degradation was extremely slow (months), while for concrete samples the degradation was extremely rapid (hours). For obvious reasons the lifetime of such compounds on different surfaces is an important factor in making operational decisions in the field, and thus there is impetus to develop field transportable systems. This presentation will summarize our current progress in development of field transportable ion trap SIMS.
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"The Improved Teeny-TOF Mass Spectrometer for Chemical and Biological Sensing"
Scott A. Ecelberger, Timothy J. Cornish, Wayne A. Bryden (Johns Hopkins University Applied Physics Laboratory)

A miniature, low voltage, reflectron time-of-flight mass spectrometer has been developed and tested on a series of compounds ranging in mass from a few hundred Da to over 50kDa. The design employs a small and commercially available 10 l/s pump, a 140uJ nitrogen laser, and fiber optics to deliver the laser energy. A gridless, focusing ion source is operating at 4.5kV, the ruggedized reflector is rolled from a flexible circuit board and encased in fiberglass, and the detector has an improved anode that reduces ringing commonly found in coaxial designs. The first prototype is currently being tested for its use in chemical and biological threat detection.
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"Multimembrane Inlet System for Mass Spectrometry Analysis"
Olga S. Viktorova, V. T.Kogan, A. K.Pavlov, Y. V. Chichagov (A. F.Ioffe Physical Technical Institute, St.Petersburg, Russia); B. M. Dubenskii, S. P. Parinov (AOZT "Analytic," St.Petersburg, Russia); A. G. Vitenberg (St.Petersburg State University, Russia); T. Kotiaho (Helsinki University, Finland); R. Ketola (VTT Chemical Technology, Helsinki, Finland)

The simulation and experimental tests of the Multimembrane Inlet System that consists of consecutively positioned sheet silicone membranes are described. The original multimembrane inlet supplies preconcentration of volatile organic compounds (VOCs) from inorganic matrices (air, water) during an unstable process of sample injecting into the ion source of a mass spectrometer. The results indicate that silicone membrane of 25-30 micrometers thickness allows to approuch an enrichment effect of compounds from matrices by designed inlet system to the maximum of magnitude (for unlimited thin membranes). Our multimembrane inlet system were used for the determination of organic and inorganic compounds in air samples. The effect of preconcentration is >100 000 by 3-membrane inlet system. The possibilities of using of multimembrane inlet system for environmental application are discussed.
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"A High-Performance Handheld Gas Chromatograph"
Conrad M. Yu (Lawrence Livermore National Laboratory)

Gas chromatography is a prominent technique for separating complex gasses and analyzing relative quantities of each separate component in the blend. This analytical technique is popular with scientists in a wide range of applications, including air and water pollution and chemical and biological analysis. Today, one of the hot topics in the analytical instrumentation community is the need to move analysis away from the laboratory to where samples ("the field") are. The need to do this is fueled by the need for quicker real time data collection and lower analysis cost. Our recent improvement on a Handheld Gas Chromatograph is developing a sample pre-concentrator unit and related electronics to improve the detection capability of trace chemical components in air. The hand-held, real time detection gas chromatograph (GC) prototype unit was developed earlier at the Micro-Technology Center of Lawrence Livermore National Laboratory by means of Micro-Electro-Mechanical-System (MEMS) technology. The total weight of this hand-held gas chromatograph is about 8 lbs. and its physical size is 8" x 5" x 3". It consumes about 12 watts of electrical power and has a response time on the order of two minutes. At present, the new detector is a Glow Discharge detector with a sensitivity of parts per billion. The average retention time is about 30 to 45 seconds. Under optimum condition, the calculated effective plate number for the MEMS silicon column is about 40K. The separation column in the portable GC is fabricated completely on silicon wafers. Silicon is a good thermal conductor and it provides a uniform temperature for the whole column together with the possibility of rapid heating and cooling of the column. The operational temperature can be as high as 350 degrees Celsius (maximum column coating temperature). The GC system is capable of rapid column temperature ramping and cooling operations. These capabilities are especially important for organic and biological analyses in GC applications.
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"Detection of 'Unknown Agents' in Harsh Environments using a Newly Developed Ruggedized Mass Spectrometer"
Kevin J. Hart, Irene F. Robbins, Marcus B. Wise, Wayne H. Griest, Stephen A. Lammert, and Cyril V. Thompson (Oak Ridge National Laboratory)

A new, ruggedized and integrated detection system for chemical and biological agents has been developed for use in field analysis. The analyzer employed in this instrument is a custom designed ion trap mass spectrometer capable of using air as the buffer gas with complete electronic control and off-line data analysis software. System components have been selected for radiation tolerance and special circumvention circuits were designed to rapidly de-power the system upon detection of a nuclear event. The vacuum system includes a turbo pump that was tested to ensure it could operate without failure when exposed to vibrations and sudden changes in orientation that might be generated by the target vehicle platforms. The additional pumping speed obtained using this pumping strategy not only permits the system to clear itself more quickly than previous systems that were based on ion getter pumps but also allows the system to use chemical ionization reagents to increase chemical selectivity. The instrument is equipped with a mode-select valve to provide rapid selection of one of three sampling systems: a vapor detection line for volatile chemical agents, a ground sampling system for liquid chemical agents and a unique aerosol concentrator/pyrolysis system for biological agents. The primary focus of this work has been the development of highly specific and reliable detection schemes for the most likely threat agents. Also of concern are agents that have not been prioritized and may include new designer agents that have been chemically modified from those typically found in the inventories of armies around the world. Additionally, toxic industrial chemicals that may be released during the course of a battle represent a potential chemical threat to soldiers in the field. This presentation will focus on the development of this instrument as a rugged chemical and biological agent detector and discuss its application to the problem of detection of "unknown" chemical agents in harsh environments.
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"A Rugged and Compact Time-of-Flight Mass Spectrometer for Fast and Sensitive Leak Detection"
Marc Gonin, Katrin Fuhrer, Michael Ugarov, Val Vaughn, Steve Ulrich, Michael McCully, Albert Schultz (Ionwerks, Inc.)

A compact Time-of-Flight mass spectrometer is being developed for air leak detection during the space shuttle start. The main challenges for this application are speed, sensitivity, dynamic range, and ruggedness. We made several approaches to address these issues for a compact TOF prototype. A rugged, filament-less ionizer has been developed, based on a surface desorption process. Advantages and current limitation of this ionizer are discussed. The sensitivity of a TOF is principally limited by the saturation of the Micro-channel-plate detector, which can handle only a few million counts per second. An approach to overcome this limitation for this application is discussed. Further a detector scheme is presented which allows to obtain a dynamic range of 10^6 per second with a time-to digital converter.
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