US20050092914A1 - NOx monitor using differential mobility spectrometry - Google Patents
NOx monitor using differential mobility spectrometry Download PDFInfo
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- US20050092914A1 US20050092914A1 US10/981,001 US98100104A US2005092914A1 US 20050092914 A1 US20050092914 A1 US 20050092914A1 US 98100104 A US98100104 A US 98100104A US 2005092914 A1 US2005092914 A1 US 2005092914A1
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N27/00—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means
- G01N27/62—Investigating or analysing materials by the use of electric, electrochemical, or magnetic means by investigating the ionisation of gases, e.g. aerosols; by investigating electric discharges, e.g. emission of cathode
- G01N27/622—Ion mobility spectrometry
- G01N27/624—Differential mobility spectrometry [DMS]; Field asymmetric-waveform ion mobility spectrometry [FAIMS]
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- A—HUMAN NECESSITIES
- A61—MEDICAL OR VETERINARY SCIENCE; HYGIENE
- A61B—DIAGNOSIS; SURGERY; IDENTIFICATION
- A61B5/00—Measuring for diagnostic purposes; Identification of persons
- A61B5/08—Detecting, measuring or recording devices for evaluating the respiratory organs
- A61B5/082—Evaluation by breath analysis, e.g. determination of the chemical composition of exhaled breath
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- G—PHYSICS
- G01—MEASURING; TESTING
- G01N—INVESTIGATING OR ANALYSING MATERIALS BY DETERMINING THEIR CHEMICAL OR PHYSICAL PROPERTIES
- G01N33/00—Investigating or analysing materials by specific methods not covered by groups G01N1/00 - G01N31/00
- G01N33/0004—Gaseous mixtures, e.g. polluted air
- G01N33/0009—General constructional details of gas analysers, e.g. portable test equipment
- G01N33/0027—General constructional details of gas analysers, e.g. portable test equipment concerning the detector
- G01N33/0036—Specially adapted to detect a particular component
- G01N33/0037—Specially adapted to detect a particular component for NOx
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02A—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE
- Y02A50/00—TECHNOLOGIES FOR ADAPTATION TO CLIMATE CHANGE in human health protection, e.g. against extreme weather
- Y02A50/20—Air quality improvement or preservation, e.g. vehicle emission control or emission reduction by using catalytic converters
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y10—TECHNICAL SUBJECTS COVERED BY FORMER USPC
- Y10T—TECHNICAL SUBJECTS COVERED BY FORMER US CLASSIFICATION
- Y10T436/00—Chemistry: analytical and immunological testing
- Y10T436/17—Nitrogen containing
- Y10T436/177692—Oxides of nitrogen
Definitions
- the present invention relates to spectrometry, and more particularly, to spectrometer devices providing chemical analysis by aspects of ion mobility in an electric field.
- Chemical detection systems are used in a wide array of applications. These devices may take samples directly from the environment, or may incorporate a front end device to separate compounds in a sample before detection. There is particular interest in providing a chemical detection system capable of accurate compound detection and identification, and which may be deployed in various venues, whether in the lab, in the workplace or in the field.
- Mass spectrometers are well known as the gold standard of laboratory-based systems operate at low pressures, resulting in complex systems, and the spectra output can be difficult to interpret, often requiring a highly trained operator.
- GC gas chromatograph
- NOx reactive nitrogen oxide species
- NOx reactive nitrogen oxide species
- NO 2 oxidized nitrogen oxide species
- NO 3 reactive nitrogen oxide species
- Tougher environmental regulations to reduce these levels in the atmosphere require higher performance detectors and monitors applied to anthropogenic sources of NOx (e.g. exhaust from internal-combustion engines, steel mill processing, power plant emissions, etc.) with higher sensitivity and faster response times.
- Enhancement of fuel economy of internal-combustion engines is another driver for the development of sensors which are able to precisely, and rapidly, monitor NOx levels in exhaust emissions.
- the medical value of detection of NO in exhaled breath has also been recognized for clinical diagnosis. For example, it has been reported that such clinical analysis can provide a noninvasive window into the activities of disease, such as asthma, chronic obstructive pulmonary disorder, and cystic fibrosis, in the lower airways. There is therefore a desire for improved, portable and simple apparatus and method for evaluation of NO in exhaled breath for medical purposes.
- IMS Ion Mobility Spectrometry
- Time-of-flight Ion Mobility Spectrometers are considered to be functional chemical detectors. High-speed response and low memory effects have been attained, and the gas phase ion chemistry inside the TOF-IMS can be highly reproducible. Widespread use, however, still remains a problem for TOF-IMS.
- TOF-IMS flow channels also referred to as drift tubes
- drift tubes are still comparatively large and expensive and suffer from losses in detection limits when made small.
- the differential ion mobility spectrometer (DMS), also known as a high field asymmetric waveform ion mobility spectrometer (FAIMS)), is an alternative to the IMS.
- DMS differential ion mobility spectrometer
- a gas sample that contains a chemical compound is subjected to an ionization source. Ions from the ionized gas sample are drawn into an ion filter region, where the ions flow in a compensated high asymmetric RF field generated between filter electrodes, the field being transverse to the ion flow.
- the field is compensated to allow selected ion species to pass through the filter, based on aspects of their mobility in the field. These ion species are passed downstream to an ion detector. Detections are correlated with field conditions and compensation and species identification is made by reference to known species behavior in the extant compensated DMS field.
- the asymmetric field alternates between a high and low field strength condition that causes the ions to move in response to the field according to their mobility characteristics.
- the mobility in the high field differs from that of the low field. That mobility difference produces a net transverse displacement of the ions as they travel in the gas flow through the filter. This transverse travel of the ions continues until they drive into one of the filter electrodes and are neutralized.
- the field is also compensated such that a particular ion species will remain toward the middle of the flow in the flow path and will pass through the filter without neutralization.
- the amount of change in mobility in response to changes in the asymmetric field is compound-dependent. This permits separation of ions from each other according to their species based on the applied compensation (usually a dc bias applied to the filter electrodes).
- MSA Mine Safety Appliances Co.
- FIS Field Ion Spectrometry
- the present invention achieves non-radioactive detection and identification of trace amounts of NOx species in a gas sample.
- method and apparatus i.e., systems
- systems are provided for non-radioactive detection and quantification of NOx in a gas sample.
- Systems of the invention are compact, with fast response times (msec scale), high sensitivity and specificity, and low manufacturing cost.
- Devices of the invention are capable of being mass-produced with broad applicability.
- Systems of the invention can detect positive NO spectra and negative NO 2 (and even NO 3 ) spectra. This detection can be performed simultaneously in a single scheme. Also, total NOx can be detected upon addition of O 2 gas to the sample to be scanned.
- a simple, practice of the invention includes Differential Mobility Spectrometry (DMS) systems which operate rapidly and can provide analytical information in real-time.
- DMS Differential Mobility Spectrometry
- These systems preferably feature non-radioactive ionization, which may be by means of a UV lamp, by corona discharge, by plasma, or by other photon sources.
- non-radioactive ionization source reduces risk to users and avoids regulatory issues as well as reducing the ionization energy to a level that avoids fragmenting or otherwise damaging the sample analytes to be detected.
- Illustrative applications of the invention include detection of NOx in combustion exhaust gas for environmental monitoring purposes or as part of a controller for improving the combustion process.
- Such innovation addresses the analytical challenge posed by increasingly strict environmental regulations applied to anthropogenic sources of NOx (e.g., exhaust from internal-combustion engines, steel mill processing, power plant emissions, etc.).
- Still another illustrative application of the invention includes a system for non-radioactive detection of NO in exhaled breath.
- detection system enables non-invasive and real-time patient health evaluations, and can be provided in a compact and low-cost package.
- DMS practices of the invention minimize the affect of moisture on analyte detection.
- moisture in a NOx sample does not affect DMS response up to about 1000 ppm and above 1000 ppm the compensation voltage increases with increasing humidity. Quite advantageously, this results in an enhanced resolving ability of the DMS in with varying levels of moisture.
- a gas sample is ionized. Ions from the ionized gas sample are drawn into a DMS ion filter and are subjected to differential ion mobility filtering to determine presence and amount of NOx.
- This DMS filtering accentuates differences in ion mobility of the ionized sample in a high-low alternating asymmetric RF field.
- the filter field is compensated such that selected ion species are allowed through the field and are passed to an ion detector. Passing of an ion species is based on high field ion mobility characteristics of the species in the changing filter field conditions. All other species are neutralized within the filter.
- Ion species identification itself follows upon downstream detection of the passed ion species and comparison of detection results against known detection behavior for the particular field conditions. In a preferred embodiment of the invention, positive and negative ion species are detected simultaneously.
- Embodiments of the invention employ compact DMS systems made according to the principles of 1) U.S. Pat. No. 6,495,823, entitled MICROMACHINED FIELD ASYMMETRIC ION MOBILITY FILTER AND DETECTION SYSTEM, by Raanan A. Miller and Erkinjon G. Nazarov, incorporated herein by reference, 2) U.S. patent application Ser. No. 10/187464, filed Jun. 28, 2002, internal Attorney Docket M070, entitled SYSTEM FOR COLLECTION OF DATA AND IDENTIFICATION OF UNKNOWN ION SPECIES IN AN ELECTRIC FIELD, by Lawrence A. Kaufman, Raanan A. Miller, Erkinjon G.
- FIG. 1A is a diagram of a fast DMS combustion control system in practice of the invention.
- FIG. 1B is a diagram of a fast DMS system for breath analysis.
- FIG. 2 ( a - d ) shows four related DMS scans of an NOx sample: (a) showing presence of NO and NO2, in N2 carrier gas; (b) same, with 1% O2 added to carrier; (c) same, taken 4 seconds after O2 removed from gas flow of (b); and (d) same, 18 seconds after shut off of O2 of (b).
- FIG. 3 shows spectra for (a) NO and (b) NO 2 in clean nitrogen transport gas, with RF voltage at 1200V; the upper scan shows the spectrum for positive ions and the lower scan shows the negative response in each.
- FIG. 4 shows concentration dependence of DMS for (a) nitric oxide and (b) nitrogen dioxide, comparing peak area (squares) to peak height (diamonds).
- FIGS. 5 a , 5 b , 5 c and 5 d show DMS spectra for negative (lower traces) and positive (higher traces) ion species for NOx samples, with transport gas at a mixture of: 23.6 ppm of SO 2 ; 121.2 ppm of H 2 ; 398 ppm of CO, 8.1% of O 2 ; 10% of CO 2 ; and N 2 as the balance gas.
- FIG. 6 shows the effect of changing NOx concentration on DMS Spectra.
- FIG. 7 shows the effect of humidity on negative mode NOx peak position and peak intensity for transport gases of clean nitrogen and the complex mixture discussed in section e.
- FIG. 8 shows the response of DMS to a transport gas composed of propene, O2, N2 and water.
- FIG. 9 shows the response of DMS when NO 2 and NO samples are added to the DMS transport gas.
- FIG. 10 is a schematic of an illustrative DMS/MS interface in application of the invention.
- FIG. 11 shows mass-spectra for positive NOx ions: (a) 20 ppm of NO in dry N 2 transport gas, (b) 20 ppm of NO in dry N 2 +O 2 (10%) transport gas, similar spectra obtained with NO 2 in dry N 2 , and (c) 20 ppm of NO in humidified N 2 transport gas.
- FIG. 12 shows mass-spectra for negative NOx ions: (a) 20 ppm of NO 2 in dry N 2 ; and (b) 20 ppm of NO in humidified N 2 , and similar spectra when NO 2 sampling.
- FIG. 13 is a table of ionization energies and proton and electron affinities.
- a DMS system 10 is coupled to a combustion 11 (such as in a factory or generator or an automotive engine or the like) for real-time control of combustion conditions resulting in cleaner combustion and improved fuel economy.
- Fuel and air are drawn into the combustion and are mixed under control of a combustion controller and are combusted in a combustion chamber 12 .
- Exhaust from the chamber includes many compounds.
- NOx and its constituents For example, inefficient burning can result in emission of high levels of HNO3, which can result in acid rain. Detection of NO and NO2 is also important in controlling combustion.
- FIG. 1A a sample of exhaust S from the combustion chamber 12 is drawn into an ionization chamber 14 .
- Selection of an ionization source is important. We have found that a source that provides soft ionization conditions is best for NOx detection of combustion components. A higher energy source can result in ionization of the nitrogen in the background air and therefore can corrupt detection and analysis of NOx constituents of the combustion effluent. A non-radioactive source is therefore preferred.
- a UV source 16 provides adequate energy to ionize the target NOx without ionization of the nitrous background. A UV lamp is a conventional soft ionization source and would be adequate and even preferred in practices of the present invention.
- the sample is ionized in chamber 14 and the ionized sample S + is flowed into the DMS filter 18 wherein it is filtered according to known DMS principles, as earlier described.
- Species detection data from detector 19 is processed to enable identification of the NOx constituents. This process is managed under control of a DMS System controller 20 . Based on such identification, a data signal is issued by the system controller 20 to the combustion controller 22 for improvement of fuel combustion.
- a data signal is issued by the system controller 20 to the combustion controller 22 for improvement of fuel combustion.
- Such detection, identification and combustion adjustments are enabled by reference to a store of known system behavior, which may be incorporated within controller 20 .
- the combustion controller of the invention performs combustion control functions which can be used to improve combustion efficiency in real-time and in real-life environments, in situ, as will be fully appreciated by a person skilled in the art.
- FIG. 1B a patent breath output is captured as sample S and is introduced into a DMS system 10 by a exhale capture device 13 for real-time detection of NO in the patent's breath.
- sample S is drawn into an ionization chamber 14 and ionization, filtering, detection and identification proceed accordingly.
- daily measurements of NO in the breath can be used to regulate medication, such as glucocorticoids, for such diseases as asthma.
- FIG. 2 shows presence of NO and NO2 in N2 carrier gas (flow rate of 6 ppm) and is a plot of intensity versus compensation voltage in the DMS filter with detection of NO at intensity of about 3.5 at about ⁇ 32 v compensation and with trace NO2 at about ⁇ 20 v.
- FIG. 2 ( b ) the conditions of FIG. 2 ( a ) were repeated but with 1% O2 added to the gas flow. Reaction of the NOx and O2 results in formation of NO2, as indicated by several intensity peaks (as shown by the arrows) at several compensation levels. It will be observed that the 1% O2 resulted in essentially total conversion of NO to NO2 in this situation.
- FIG. 2 ( c ) the conditions of FIG. 2 ( a ) were repeated but and a reading was taken 4 seconds after the O2 was removed from the gas flow. Owing to some latency in the system, some amount of O2 remains in the flow path as indicated by the moderate presence of N02 detected at about ⁇ 21 compensation, and the return of NO as seen at ⁇ 33 compensation.
- FIG. 2 ( d ) the conditions of FIG. 2 ( a ) were repeated but with 1% O2 added to the gas flow and the detection was made 18 seconds after shut off of the O2.
- FIG. 2 ( d ) shows that the O2 has cleared the flow path 18 seconds after it was removed from the flow. No attempt was made to accelerate this clearing, as might be done by heating or other purging processes. Nonetheless, this shows that the system has purged and nearly returned to the condition of FIG. 2 ( a ). Furthermore, under realistic operating conditions, at elevated temperatures, the sample would be purged all the more readily.
- Each of these frames shows both positive and negative mode detections for the NOx constituents of the sample in practice of the invention.
- Positive and negative mode detections are made in practice of a preferred compact DMS embodiments of the invention as taught in Ser. No. 10/187464, as incorporated herein.
- a controlled gas flow can be used for detection of NOx and its constituents, and that such is achieved with high resolution and specificity. This process is both repeatable and predictable.
- FIG. 13 shows the typical chemical composition of an engine exhaust. Select ion energy properties of these components are: ionization energy (EI), electron (EA) and proton affinity (PA), and potential for ion formation via a UV ionization source with photon energy of 10.67 eV.
- EI ionization energy
- EA electron
- PA proton affinity
- ion formation will occur as follows: free electrons which are formed due to photo-ionization of NOx and propene molecules, at atmospheric pressure conditions, will be captured by components which have positive electron affinity. In our experimental conditions, it may be oxygen, CO, and nitrogen dioxide molecules. NO 2 molecules have significantly higher proton affinity compared with the other components. Given sufficient time all free electrons will be transferred to the nitrogen dioxide molecules. Therefore, based only on ion energetic arguments it is expected that with UV ionization, and monitoring of the DMS negative spectra, it should be possible to detect and monitor different levels of NO 2 in an exhaust stream.
- Standard gases includes NO 1500 ppm balanced with nitrogen, NO 1500 ppm, NO2 1500 ppm.
- Drift Gas was grade 5 nitrogen (99.9995%).
- the drift gas (nitrogen) was flowed at 1500 cc/min, with a range of DMS compensation voltage (CV) between ⁇ 45V and +12V, with scan time at 1 sec.
- Mass flow controllers were used at 2000 cc/min, 100 cc/min, 50 cc/min and 10 cc/min for nitrogen and 50 cc/min for oxygen. Performance was at room temperature. Drift gas and NOx standard gases were introduced and mixed via MFCs at designated levels. Oxygen at 10% was introduced with a flow controller for NO/NO2 dynamic determination.
- FIG. 3 shows individual spectra for NO ( FIG. 3 a ) and NO 2 ( FIG. 3 b ) samples.
- FIG. 3 illustrates that the DMS has the ability to directly measure the amounts of both NO and NO 2 species actually existing in the mixture.
- the positive ion spectra provides information on the NO species while the negative ion spectra provides information on the amount of NO 2 (or NO 3 ) species present.
- FIG. 4 shows the DMS intensity response to different concentrations of NO (positive polarity ions) and NO 2 (negative polarity ions) samples.
- Plots for peak height (blue) and for peak area (pink) are presented.
- Y 4.6x-6.1 e.g. for area) up to 6 ppm.
- the resulting reactions for positive and negative ion formation have different reaction orders. Positive ion formation has a first reaction order while the negative ion formation has a second reaction order.
- the estimated limit of detection for both chemicals according to FIG. 4 are 0.3 ppm for NO and 1 ppm for NO 2 .
- the transport gas used had the following composition: 23.6 ppm of SO 2 ; 121.2 ppm of H 2 ; 398 ppm of CO, 8.1% of O 2 ; 10% of CO 2 ; with nitrogen as the balance gas.
- the transport gas flow rate was 400 cc/min.
- the NO 2 flow rate was constant at 5 cc/min and concentration of NO 2 in sample mixture was 1500 ppm.
- NO flow rate varied from 0.62 cc/min to 10 cc/min and concentration of NO in sample mixture was 1500 pp.
- FIG. 5 ( a,b,c,d ) shows the results of these experiments.
- the positive ion peaks have different positions compared to when only the nitrogen transport gas is used, but the negative ion peak has the same compensation voltage seen for NO 2 .
- One explanation of this result is due to the presence of oxygen (10%) which can oxidize the NO and produce neutral NO 2 (or NO 3 ).
- NO 3 has very high electron affinity and will form negative ions by direct capture of free electrons, or by electron exchange processes from negative ions of O 2 and CO which may have formed earlier but which have significantly lower electron affinities (EA).
- EA electron affinities
- Simultaneous introduction of NO (36 ppm) and NO 2 (18 ppm) increases the intensity of the negative ion peak (see FIG. 5 d ).
- the response of the DMS to different total amounts of NOx is shown in FIG. 6 a .
- Concentration dependence plots for peak area and peak height are shown in FIG. 6 b . The two plots look similar, indicating that the peak form does not change.
- the estimated limit of detection for NOx under these conditions is around 2 ppm.
- FIG. 7 shows results of peak position and peak intensity for the negative ions plotted at different moisture levels.
- the moisture does not affect the DMS response up to about 1000 ppm.
- the compensation voltage increases with increasing humidity, i.e., shifts the peak to a more negative value away from the zero axis. This results in an enhanced resolving ability of the DMS as the moisture level increases.
- the intensity of peak decreases, but rather gradually (increasing the moisture level from 1000 ppm (relative humidity 4%) to 21000 ppm (relative humidity 85%) changes the intensity from 6V down to 3.0V) as shown in FIG. 7 .
- Results of varying the humidity produce similar peak positions shifts and peak intensities with both the mixture and nitrogen transport gases.
- Real exhaust typically contains many hydrocarbons. Propene is historically used as a representative compound for the hydrocarbon matrix in exhaust gas.
- FIG. 8 shows the DMS spectra for a transport gas containing 100 ppm propene, 10% oxygen in clean nitrogen with moisture at a 70 C dew point.
- This peak is the same as the one observed for the NO 2 sample. From mass spectrometric analysis this peak has been determined to be an NO 3 related peak.
- the negative mode DMS spectra shows a characteristic response for the total NOx sample.
- FIG. 1A 0 shows a schematic of a preferred micromachined DMS coupled to a mass spectrometer.
- a photo-ionization source was attached to the DMS sensor for ionization, and a Teflon base was interfaced to pneumatically attach the DMS to the flange of a TAGA 6000 APCI-tandem mass spectrometer (MS/MS) from Sciex, Inc. (Toronto, Ontario, Canada).
- MS/MS was equipped with a computer and API Standard Software, Ver 2.5.1 (PE SCIEX).
- Analytes (NOx) were introduced with transport gas and ionized before introduction into ion filter region of the DMS. Once through the filter region, the ions were injected through a hole in the detector electrode, into the pinhole of the interface plate of the MS/MS.
- Polarity of injected MS ions could be changed by changing the polarity of the deflector electrode.
- the significant advantage of this interface is that, under the effect of the deflector voltage and mass-spectrometer plenum gas, the analyzed ions are completely isolated from analyte neutrals exhausted by the DMS transport gas.
- Another advantage of this interface is the possibility to simultaneously record DMS and MS spectra.
- FIG. 11 shows positive ion mass spectra for 20 ppm NO in dry N 2 , FIG. 11 a , and FIG. 11 b , when 10% of oxygen was added to the dry transport gas (N 2 ).
- N 2 dry transport gas
- the NO mass-spectra contains two series of ions: related to monomer and cluster nitric oxide ions W n NO + and proton bounded water ions W k H + .
- the level of water (W) clustering depends on the moisture level. For dry conditions, with humidity less than 10 ppm; the values of n and k may vary from 0 to 4.
- heavier water clusters also appear: 91[W 5 H + ]; 109[W 6 H + ]; 127[W 7 H + ]; 145[W 8 H + ]; 163[W 9 H + ];181[W 10 H + ]; 199[W 11 H + ].
- the nitrogen dioxide and nitric oxide positive ions mass spectra are significantly different.
- the last two peaks show that a process of dissociation of NO 2 molecules to NO+O certainly exists. This is likely key to considering future oxidizing of NO 2 molecules to NO 3 by a series of chemical reaction steps (see, e.g. reactions (1)).
- the photoionization source could not directly provide ionization of water molecules.
- a mechanism to explain formation of proton bounded water ions may be described by the following sequence of gas phase reactions: NO+hv ⁇ NO + +e ⁇ NO + +W+M ⁇ W NO + +M W NO + +W+M ⁇ W 2 NO + +M W n-1 NO + +W+M ⁇ W n NO + +M, (3) where M is a non-reacting molecule, generally N 2 .
- NO samples are shown to produce a spectra containing only positive ion peaks. As expected there are no negative ions produced.
- NO 2 samples produce spectra containing a number of low intensity peaks in the positive mode (including a peak with the same compensation voltage as observed with the pure NO sample) and one major peak in the negative polarity mode.
- the NO spectra even at room temperature in the presence of oxygen, is transformed into a spectrum representative of the NO 2 sample. Concentration dependence of NO and NO 2 samples have different approximations: NO has linear and NO 2 has quadratic approximation.
- the estimated limit of detection for both species is around 1 ppm. Even in the presence of interferants, the negative ion spectra is stable and provides sufficient accuracy for NOx monitoring under real world conditions.
- the present invention provides direct measurement of NOx, including NO and NO 2 .
- Further applications include an all-in-one detector that can make measurement of both hydrocarbon and NOx content in a gas sample in real-time.
- an all-in-one detector that can make measurement of both hydrocarbon and NOx content in a gas sample in real-time.
- the present invention enables a compact system for other detection needs, such as detection of NO in exhaled breath for monitoring and treatment of medical conditions.
- the present invention therefore has applications to these and other medical treatments as will be apparent to a person skilled in the art.
- Apparatus of the invention may feature planar, cylindrical, radial, or other DMS topologies and configurations.
- a preferred DMS embodiment of the invention enables a practical, small, fast ( ⁇ 100 msec), non-radioactive, sensitive and selective detector for real time monitoring of NOx.
Abstract
Description
- This application claims priority to U.S. Provisional Application Ser. No. 60/418,235, filed Oct. 12, 2002, entitled FAIMS METHOD AND APPARATUS FOR NOX DETECTION AND ANALYSIS, by Raanan A. Miller, Erkinjon G. Nazarov, and Muning Zhong. The entire teachings of the above application are incorporated herein by reference.
- The present invention relates to spectrometry, and more particularly, to spectrometer devices providing chemical analysis by aspects of ion mobility in an electric field.
- Chemical detection systems are used in a wide array of applications. These devices may take samples directly from the environment, or may incorporate a front end device to separate compounds in a sample before detection. There is particular interest in providing a chemical detection system capable of accurate compound detection and identification, and which may be deployed in various venues, whether in the lab, in the workplace or in the field.
- Mass spectrometers are well known as the gold standard of laboratory-based systems operate at low pressures, resulting in complex systems, and the spectra output can be difficult to interpret, often requiring a highly trained operator.
- At times a gas chromatograph (GC) is used as a front-end to an MS, with good results. But the GC-MS is not well-suited for small, low cost, fieldable instruments for real-time chemical detection. Nevertheless there is a continuing need for fieldable instruments generation of real-time detection data.
- Detection of species of NOx is a good example of this need. It is well known that reactive nitrogen oxide species NOx such as NO, NO2, and NO3 play a major role in atmospheric chemistry. These species are important in the ozone and nitrogen cycles, which produce detrimental photochemical smog and acid rain. Tougher environmental regulations to reduce these levels in the atmosphere require higher performance detectors and monitors applied to anthropogenic sources of NOx (e.g. exhaust from internal-combustion engines, steel mill processing, power plant emissions, etc.) with higher sensitivity and faster response times. Enhancement of fuel economy of internal-combustion engines is another driver for the development of sensors which are able to precisely, and rapidly, monitor NOx levels in exhaust emissions.
- The medical value of detection of NO in exhaled breath has also been recognized for clinical diagnosis. For example, it has been reported that such clinical analysis can provide a noninvasive window into the activities of disease, such as asthma, chronic obstructive pulmonary disorder, and cystic fibrosis, in the lower airways. There is therefore a desire for improved, portable and simple apparatus and method for evaluation of NO in exhaled breath for medical purposes.
- There are a number of reliable measurement techniques which have been developed for monitoring nitrogen oxide species: These include ion-based detection, chemiluminesence, electrochemical, acoustic gas sensors, and ZrO2 solid electrolyte sensors, laser systems, and the like. These techniques, however, generally require sophisticated optical equipment, or suffer from significant drawbacks such as slow response times, or the detection of only certain NOx species, making them problematic for routine measurements.
- Ion Mobility Spectrometry (IMS) has been explored recently as an approach to realizing a more sensitive, selective and robust device for NOx monitoring. In dry (humidity ˜10 ppm) operating conditions, the IMS shows high sensitivity (10's of ppms) and fast response times (10's of ms). However, a serious disadvantage is that its response is highly affected by the presence of moisture. For example, in one demonstration, a level of 3% humidity completely suppressed IMS response to a sample at 483 ppm NO2.
- Time-of-flight Ion Mobility Spectrometers (TOF-IMS) are considered to be functional chemical detectors. High-speed response and low memory effects have been attained, and the gas phase ion chemistry inside the TOF-IMS can be highly reproducible. Widespread use, however, still remains a problem for TOF-IMS. Among other things, TOF-IMS flow channels (also referred to as drift tubes) are still comparatively large and expensive and suffer from losses in detection limits when made small.
- The differential ion mobility spectrometer ((DMS), also known as a high field asymmetric waveform ion mobility spectrometer (FAIMS)), is an alternative to the IMS. In a DMS device, a gas sample that contains a chemical compound is subjected to an ionization source. Ions from the ionized gas sample are drawn into an ion filter region, where the ions flow in a compensated high asymmetric RF field generated between filter electrodes, the field being transverse to the ion flow. The field is compensated to allow selected ion species to pass through the filter, based on aspects of their mobility in the field. These ion species are passed downstream to an ion detector. Detections are correlated with field conditions and compensation and species identification is made by reference to known species behavior in the extant compensated DMS field.
- The asymmetric field alternates between a high and low field strength condition that causes the ions to move in response to the field according to their mobility characteristics. Typically the mobility in the high field differs from that of the low field. That mobility difference produces a net transverse displacement of the ions as they travel in the gas flow through the filter. This transverse travel of the ions continues until they drive into one of the filter electrodes and are neutralized. However, the field is also compensated such that a particular ion species will remain toward the middle of the flow in the flow path and will pass through the filter without neutralization. The amount of change in mobility in response to changes in the asymmetric field is compound-dependent. This permits separation of ions from each other according to their species based on the applied compensation (usually a dc bias applied to the filter electrodes).
- In the past, Mine Safety Appliances Co. (MSA) made an attempt at a functional cylindrical FAIMS device with coaxial electrodes, such as disclosed in U.S. Pat. No. 5,420,424. (This FAIMS technology is referred to by MSA as Field Ion Spectrometry (FIS).) The device has been found to be complex, with many parts, and somewhat limited in utility.
- It is a therefore an object of the present invention to provide a functional, small, spectrometer that overcomes the limitations of the prior art.
- It is another object of the present invention to provide a chemical sensor with fast response times for real-time process control, especially for detection and identification of NOx related species in real-time.
- It is another object of the present invention to provide a chemical sensor for detection and identification of NOx related species in real-time with minimized effect of moisture upon detection results.
- It is yet another object of the present invention to provide low cost and compact, reliable instrumentation that is useful for laboratory and field conditions and is capable of making in situ measurements of chemicals present in complex mixtures at various venues.
- The present invention achieves non-radioactive detection and identification of trace amounts of NOx species in a gas sample. In various embodiment of the invention, method and apparatus (i.e., systems) are provided for non-radioactive detection and quantification of NOx in a gas sample. Systems of the invention are compact, with fast response times (msec scale), high sensitivity and specificity, and low manufacturing cost. Devices of the invention are capable of being mass-produced with broad applicability.
- Systems of the invention can detect positive NO spectra and negative NO2 (and even NO3) spectra. This detection can be performed simultaneously in a single scheme. Also, total NOx can be detected upon addition of O2 gas to the sample to be scanned.
- In practice of the invention of preferred embodiments of the invention, it is possible to detect NOx constituents in a single analytical scheme. A simple, practice of the invention includes Differential Mobility Spectrometry (DMS) systems which operate rapidly and can provide analytical information in real-time. These systems preferably feature non-radioactive ionization, which may be by means of a UV lamp, by corona discharge, by plasma, or by other photon sources. Use of a non-radioactive ionization source reduces risk to users and avoids regulatory issues as well as reducing the ionization energy to a level that avoids fragmenting or otherwise damaging the sample analytes to be detected.
- Illustrative applications of the invention include detection of NOx in combustion exhaust gas for environmental monitoring purposes or as part of a controller for improving the combustion process. Such innovation addresses the analytical challenge posed by increasingly strict environmental regulations applied to anthropogenic sources of NOx (e.g., exhaust from internal-combustion engines, steel mill processing, power plant emissions, etc.).
- Still another illustrative application of the invention includes a system for non-radioactive detection of NO in exhaled breath. Such detection system enables non-invasive and real-time patient health evaluations, and can be provided in a compact and low-cost package.
- It has also been found that DMS practices of the invention minimize the affect of moisture on analyte detection. In one practice of the invention, moisture in a NOx sample does not affect DMS response up to about 1000 ppm and above 1000 ppm the compensation voltage increases with increasing humidity. Quite advantageously, this results in an enhanced resolving ability of the DMS in with varying levels of moisture.
- In an illustrative DMS practice of the present invention, a gas sample is ionized. Ions from the ionized gas sample are drawn into a DMS ion filter and are subjected to differential ion mobility filtering to determine presence and amount of NOx.
- This DMS filtering accentuates differences in ion mobility of the ionized sample in a high-low alternating asymmetric RF field. The filter field is compensated such that selected ion species are allowed through the field and are passed to an ion detector. Passing of an ion species is based on high field ion mobility characteristics of the species in the changing filter field conditions. All other species are neutralized within the filter.
- Ion species identification itself follows upon downstream detection of the passed ion species and comparison of detection results against known detection behavior for the particular field conditions. In a preferred embodiment of the invention, positive and negative ion species are detected simultaneously.
- Embodiments of the invention employ compact DMS systems made according to the principles of 1) U.S. Pat. No. 6,495,823, entitled MICROMACHINED FIELD ASYMMETRIC ION MOBILITY FILTER AND DETECTION SYSTEM, by Raanan A. Miller and Erkinjon G. Nazarov, incorporated herein by reference, 2) U.S. patent application Ser. No. 10/187464, filed Jun. 28, 2002, internal Attorney Docket M070, entitled SYSTEM FOR COLLECTION OF DATA AND IDENTIFICATION OF UNKNOWN ION SPECIES IN AN ELECTRIC FIELD, by Lawrence A. Kaufman, Raanan A. Miller, Erkinjon G. Nazarov, Evgeny Krylov, Gary Eiceman, incorporated herein by reference, and/or 3) U.S. patent application Ser. No. 10/462206, entitled SYSTEM FOR COLLECTION OF DATA AND IDENTIFICATION OF UNKNOWN ION SPECIES IN AN ELECTRIC FIELD, by Lawrence A. Kaufman, Raanan A. Miller, Erkinjon G. Nazarov, Evgeny Krylov, Gary Eiceman, incorporated herein by reference.
- These and other aspects of the present invention are set forth below.
- The disclosed and other objects, features and advantages of the invention will be apparent from the following description of illustrative and preferred embodiments of the invention, and as illustrated in the accompanying drawings in which like reference characters refer to the same parts throughout the different views. The drawings are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention, wherein:
-
FIG. 1A is a diagram of a fast DMS combustion control system in practice of the invention. -
FIG. 1B is a diagram of a fast DMS system for breath analysis. -
FIG. 2 (a-d) shows four related DMS scans of an NOx sample: (a) showing presence of NO and NO2, in N2 carrier gas; (b) same, with 1% O2 added to carrier; (c) same, taken 4 seconds after O2 removed from gas flow of (b); and (d) same, 18 seconds after shut off of O2 of (b). -
FIG. 3 shows spectra for (a) NO and (b) NO2 in clean nitrogen transport gas, with RF voltage at 1200V; the upper scan shows the spectrum for positive ions and the lower scan shows the negative response in each. -
FIG. 4 shows concentration dependence of DMS for (a) nitric oxide and (b) nitrogen dioxide, comparing peak area (squares) to peak height (diamonds). -
FIGS. 5 a, 5 b, 5 c and 5 d show DMS spectra for negative (lower traces) and positive (higher traces) ion species for NOx samples, with transport gas at a mixture of: 23.6 ppm of SO2; 121.2 ppm of H2; 398 ppm of CO, 8.1% of O2; 10% of CO2; and N2 as the balance gas. -
FIG. 6 shows the effect of changing NOx concentration on DMS Spectra. -
FIG. 7 shows the effect of humidity on negative mode NOx peak position and peak intensity for transport gases of clean nitrogen and the complex mixture discussed in section e. -
FIG. 8 shows the response of DMS to a transport gas composed of propene, O2, N2 and water. -
FIG. 9 shows the response of DMS when NO2 and NO samples are added to the DMS transport gas. -
FIG. 10 is a schematic of an illustrative DMS/MS interface in application of the invention. -
FIG. 11 shows mass-spectra for positive NOx ions: (a) 20 ppm of NO in dry N2 transport gas, (b) 20 ppm of NO in dry N2+O2 (10%) transport gas, similar spectra obtained with NO2 in dry N2, and (c) 20 ppm of NO in humidified N2 transport gas. -
FIG. 12 shows mass-spectra for negative NOx ions: (a) 20 ppm of NO2 in dry N2; and (b) 20 ppm of NO in humidified N2, and similar spectra when NO2 sampling. -
FIG. 13 is a table of ionization energies and proton and electron affinities. - We are able to detect NOx, NO2, N2O4, HNO3, among other constituents, in a gas sample of NOx, and we are able to distinguished between such constituents in a single analytical framework. Systems of the invention obtain actual measurement of NOx activity in a changing environment in real-time. Applications include combustion control, whether for automotive engines or commercial furnaces or locomotives, or marine engines or the like, or medical tools, for example.
- Turning to
FIG. 1A , in a preferred illustrative embodiment of the invention, aDMS system 10 is coupled to a combustion 11 (such as in a factory or generator or an automotive engine or the like) for real-time control of combustion conditions resulting in cleaner combustion and improved fuel economy. Fuel and air are drawn into the combustion and are mixed under control of a combustion controller and are combusted in acombustion chamber 12. Exhaust from the chamber includes many compounds. Of high interest is NOx and its constituents. For example, inefficient burning can result in emission of high levels of HNO3, which can result in acid rain. Detection of NO and NO2 is also important in controlling combustion. - In
FIG. 1A , a sample of exhaust S from thecombustion chamber 12 is drawn into anionization chamber 14. Selection of an ionization source is important. We have found that a source that provides soft ionization conditions is best for NOx detection of combustion components. A higher energy source can result in ionization of the nitrogen in the background air and therefore can corrupt detection and analysis of NOx constituents of the combustion effluent. A non-radioactive source is therefore preferred. AUV source 16 provides adequate energy to ionize the target NOx without ionization of the nitrous background. A UV lamp is a conventional soft ionization source and would be adequate and even preferred in practices of the present invention. - In
FIG. 1A , the sample is ionized inchamber 14 and the ionized sample S+ is flowed into theDMS filter 18 wherein it is filtered according to known DMS principles, as earlier described. Species detection data fromdetector 19 is processed to enable identification of the NOx constituents. This process is managed under control of aDMS System controller 20. Based on such identification, a data signal is issued by thesystem controller 20 to thecombustion controller 22 for improvement of fuel combustion. Such detection, identification and combustion adjustments are enabled by reference to a store of known system behavior, which may be incorporated withincontroller 20. - Because we can distinguish the effects of humidity on analytical results, we can provide real-world, real-time and accurate detection of NOx and its constituents, unlike IMS systems. Therefore, the combustion controller of the invention performs combustion control functions which can be used to improve combustion efficiency in real-time and in real-life environments, in situ, as will be fully appreciated by a person skilled in the art.
- Other embodiments of the invention enable portable medical equipment for detection of NO in patient breath as a non-invasive diagnostic, such as for of lower airway diagnosis. Turning to
FIG. 1B , a patent breath output is captured as sample S and is introduced into aDMS system 10 by aexhale capture device 13 for real-time detection of NO in the patent's breath. As inFIG. 1A , sample S is drawn into anionization chamber 14 and ionization, filtering, detection and identification proceed accordingly. In an illustrative application, daily measurements of NO in the breath can be used to regulate medication, such as glucocorticoids, for such diseases as asthma. - An Illustration of the Invention:
- An illustrative operation of the invention is discussed with reference to
FIG. 2 , in which four related DMS scans of a NOx sample are shown (Frames a-d).FIG. 2 (a) shows presence of NO and NO2 in N2 carrier gas (flow rate of 6 ppm) and is a plot of intensity versus compensation voltage in the DMS filter with detection of NO at intensity of about 3.5 at about −32 v compensation and with trace NO2 at about −20 v. - In
FIG. 2 (b) the conditions ofFIG. 2 (a) were repeated but with 1% O2 added to the gas flow. Reaction of the NOx and O2 results in formation of NO2, as indicated by several intensity peaks (as shown by the arrows) at several compensation levels. It will be observed that the 1% O2 resulted in essentially total conversion of NO to NO2 in this situation. - In
FIG. 2 (c) the conditions ofFIG. 2 (a) were repeated but and a reading was taken 4 seconds after the O2 was removed from the gas flow. Owing to some latency in the system, some amount of O2 remains in the flow path as indicated by the moderate presence of N02 detected at about −21 compensation, and the return of NO as seen at −33 compensation. - In
FIG. 2 (d), the conditions ofFIG. 2 (a) were repeated but with 1% O2 added to the gas flow and the detection was made 18 seconds after shut off of the O2.FIG. 2 (d) shows that the O2 has cleared theflow path 18 seconds after it was removed from the flow. No attempt was made to accelerate this clearing, as might be done by heating or other purging processes. Nonetheless, this shows that the system has purged and nearly returned to the condition ofFIG. 2 (a). Furthermore, under realistic operating conditions, at elevated temperatures, the sample would be purged all the more readily. - Each of these frames shows both positive and negative mode detections for the NOx constituents of the sample in practice of the invention. Positive and negative mode detections are made in practice of a preferred compact DMS embodiments of the invention as taught in Ser. No. 10/187464, as incorporated herein.
- It will thus be appreciated that in practice of the invention, a controlled gas flow can be used for detection of NOx and its constituents, and that such is achieved with high resolution and specificity. This process is both repeatable and predictable.
- Ion energy considerations for photo-ionization and ion formation of NOx species in air at atmospheric pressure in practice of the invention are provided below.
- First, an understanding of the ion energetics and ion chemistry is provided, as this is part of the understanding of operation of the preferred DMS method and apparatus of the invention and is a foundation for interpreting the resulting spectra.
- As an illustration,
FIG. 13 shows the typical chemical composition of an engine exhaust. Select ion energy properties of these components are: ionization energy (EI), electron (EA) and proton affinity (PA), and potential for ion formation via a UV ionization source with photon energy of 10.67 eV. - Analysis of the data from
FIG. 13 shows that only NO, NO2, and propene species have an ionization energy lower than the photon energy (10.6 eV) provided by the UV ionization lamp used in this work. Consequently only these three components of the exhaust gas will directly form ions, in this case positive ions. The other components cannot directly form ions. However, there are other pathways for ion formation at atmospheric pressure due to proton and electron charge exchange reactions. For example in the positive mode, due to proton transfer reactions, we expect formation of ion species with the highest proton affinity. These are propene and protonated water cluster ions. In the negative mode, ion formation will occur as follows: free electrons which are formed due to photo-ionization of NOx and propene molecules, at atmospheric pressure conditions, will be captured by components which have positive electron affinity. In our experimental conditions, it may be oxygen, CO, and nitrogen dioxide molecules. NO2 molecules have significantly higher proton affinity compared with the other components. Given sufficient time all free electrons will be transferred to the nitrogen dioxide molecules. Therefore, based only on ion energetic arguments it is expected that with UV ionization, and monitoring of the DMS negative spectra, it should be possible to detect and monitor different levels of NO2 in an exhaust stream. - In an illustrative practice of the invention with UV ionization, a Krypton filled UV lamp (PID Lamp λ=123.9 nm and 116.9 nm with energies 10.0 eV and 10.6 eV) was used. Standard gases includes NO 1500 ppm balanced with nitrogen, NO 1500 ppm, NO2 1500 ppm. Drift Gas was
grade 5 nitrogen (99.9995%). The drift gas (nitrogen) was flowed at 1500 cc/min, with a range of DMS compensation voltage (CV) between −45V and +12V, with scan time at 1 sec. RF voltage was at 1200V,. Scans to average=1, Steps to average=1, Number of steps/scan=250. Mass flow controllers (MFC) were used at 2000 cc/min, 100 cc/min, 50 cc/min and 10 cc/min for nitrogen and 50 cc/min for oxygen. Performance was at room temperature. Drift gas and NOx standard gases were introduced and mixed via MFCs at designated levels. Oxygen at 10% was introduced with a flow controller for NO/NO2 dynamic determination. - A preliminary set of control experiments was conducted prior to introduction of real samples. First, the DMS system was run with a transport gas of pure nitrogen to verify that the background spectrum was clean. As expected, no peaks were observed in both positive and negative modes. When small amounts of NOx samples were mixed with the transport gas, peaks appeared in the DMS spectra which behaved consistently with ion energetic considerations of the analytes. NO samples produced dominant positive ion peaks and NO2 samples exhibited mostly negative ion peaks.
- NO and NO2 Spectra in Positive and Negative Modes
-
FIG. 3 shows individual spectra for NO (FIG. 3 a) and NO2 (FIG. 3 b) samples. As expected, the NO sample spectra shows a single positive peak at Vc=−23V. The low intensity negative peak around Vc=0V is believed to be an impurity. - The NO2 sample spectra showed a major single peak in the negative mode at Vc˜−10V. Two peaks with relatively small intensities are also apparent in the positive polarity at Vc=−23V (same location as for the NO sample), and at Vc=−17V. These positive peaks are believed related to NO+ and NO2 + and may be formed due to photolysis of the NO2 molecules into NO, O, and a combination of these molecular species (e.g. NO3), as shown in equation (1):
NO2+hv→NO+O
NO2+O+M→NO3+M
NO2+e−→NO2 − (1)
NO2 −+NO3→NO2+NO3 −
NO2 −+NO2→NO+NO3 − - Because molecules of NO2 and NO3 have very high electron affinities (2.3 and 3.9 eV respectively), these species will capture electrons from the other compounds (including unidentified impurities) due to charge exchange processes, and form negative ion species. This may explain the presence of a stable single peak in the negative spectra. In this model the intensity of the negative peak should be proportional to the concentration of NOx in the gas mixture.
- It is well known that mixtures of NO and NO2 exist in dynamic equilibrium with their relative concentrations dependant on experimental conditions.
FIG. 3 illustrates that the DMS has the ability to directly measure the amounts of both NO and NO2 species actually existing in the mixture. The positive ion spectra, provides information on the NO species while the negative ion spectra provides information on the amount of NO2 (or NO3) species present. This was confirmed by a validating experiment performed by oxidizing NO. 10% of oxygen was added to the standard nitrogen transport gas and blended with the standard NO sample. This resulted in a decreased intensity of the positive NO ion peak at Vc=−23V and simultaneously an increase in the intensity of the positive ion peak at Vc=−17V. Meanwhile in the negative polarity, a new peak at Vc=−10V, related to NO2 appeared. After the oxygen flow was turned off, the peaks transformed back to the characteristic NO spectra. - Concentration Dependences for NO and NO2 Species
-
FIG. 4 (a & b) shows the DMS intensity response to different concentrations of NO (positive polarity ions) and NO2 (negative polarity ions) samples. Plots for peak height (blue) and for peak area (pink) are presented. One can see that for NO these plots have a linear range (Y=4.6x-6.1 e.g. for area) up to 6 ppm. The NO2 plots are nonlinear but can be fitted very well by quadratic approximations (Y=0.0055x2+1.65x-1.9 for area plot). The resulting reactions for positive and negative ion formation have different reaction orders. Positive ion formation has a first reaction order while the negative ion formation has a second reaction order. This means that the rate of negative ion formation is increased with increasing concentration of NO2. One of the possible explanations is that in the negative mode NO and NO2 are oxidized to NO3 producing the negative spectral peak. The oxidation process may be enhanced due to the UV lamp radiation, according to reactions (1). Another mechanism which is specific for nitrogen dioxide is due to collision of neutral molecules of NO2 with oxygen atoms resulting in their transformation from one molecule to other.
NO2(g)+NO2(g)=NO3(g)+NO(g) (2) - With increasing concentration of NO2 the rate of this reaction increases due to increasing collision frequency. In this case, the amount of free electrons is increased due to ionization of NO resulting in positive ions (NO has the lowest ionization energy) and a second product NO3 which has the highest electron affinity (3.9 eV). This results in a condition favoring increased efficiency of negative ion formation. The estimated limit of detection for both chemicals according to
FIG. 4 are 0.3 ppm for NO and 1 ppm for NO2. - NO and NO2 Spectra in Positive and Negative Modes for Complex Transport Gases
- Laboratory tests were also conducted with more complex, and realistic, transport gases. The transport gas used had the following composition: 23.6 ppm of SO2; 121.2 ppm of H2; 398 ppm of CO, 8.1% of O2; 10% of CO2; with nitrogen as the balance gas. In this part of work the transport gas flow rate was 400 cc/min. As used, the NO2 flow rate was constant at 5 cc/min and concentration of NO2 in sample mixture was 1500 ppm. NO flow rate varied from 0.62 cc/min to 10 cc/min and concentration of NO in sample mixture was 1500 pp.
FIG. 5 (a,b,c,d) shows the results of these experiments. - No peaks in both the positive and negative spectra are evident in the background gas mixture shown in
FIG. 5 a. This is because all the components of this gas mixture have significantly higher ionization energies than the photon energy provided by the UV lamp. Consequently, no positive or negative ions will form directly. After introduction of 18 ppm NO2 the negative ion peak at Vc=−10.5V appeared, and only traces of the positive ions (seeFIG. 5 b) were seen. This condition is a similar to the case when only clean nitrogen transport gas was passed through the DMS (seeFIG. 3 b). When NO at 36 ppm was added,FIG. 5 c, simultaneously both positive and negative ion peaks were observed. The positive ion peaks have different positions compared to when only the nitrogen transport gas is used, but the negative ion peak has the same compensation voltage seen for NO2. One explanation of this result is due to the presence of oxygen (10%) which can oxidize the NO and produce neutral NO2 (or NO3). NO3 has very high electron affinity and will form negative ions by direct capture of free electrons, or by electron exchange processes from negative ions of O2 and CO which may have formed earlier but which have significantly lower electron affinities (EA). Simultaneous introduction of NO (36 ppm) and NO2 (18 ppm) increases the intensity of the negative ion peak (seeFIG. 5 d). - The response of the DMS to different total amounts of NOx is shown in
FIG. 6 a. One can see that the peak position for the negative ions remains the same, and only the peak intensity changes. Concentration dependence plots for peak area and peak height are shown inFIG. 6 b. The two plots look similar, indicating that the peak form does not change. The estimated limit of detection for NOx under these conditions is around 2 ppm. - Effect of Moisture (H2O) on DMS Negative Ion Spectra
- One significant disadvantage of conventional IMS is the suppression of its response to NOx species as humidity levels increase. The DMS response to NOx species at different moisture levels was therefore closely studied.
FIG. 7 , shows results of peak position and peak intensity for the negative ions plotted at different moisture levels. - As is evident in
FIG. 7 , the moisture does not affect the DMS response up to about 1000 ppm. Above 1000 ppm the compensation voltage increases with increasing humidity, i.e., shifts the peak to a more negative value away from the zero axis. This results in an enhanced resolving ability of the DMS as the moisture level increases. The intensity of peak decreases, but rather gradually (increasing the moisture level from 1000 ppm (relative humidity 4%) to 21000 ppm (relative humidity 85%) changes the intensity from 6V down to 3.0V) as shown inFIG. 7 . Results of varying the humidity produce similar peak positions shifts and peak intensities with both the mixture and nitrogen transport gases. - Effect of Propene on Detection of NO/NO2
- Real exhaust typically contains many hydrocarbons. Propene is historically used as a representative compound for the hydrocarbon matrix in exhaust gas.
FIG. 8 shows the DMS spectra for a transport gas containing 100 ppm propene, 10% oxygen in clean nitrogen with moisture at a 70 C dew point. - The resultant spectra shows a propene peak in the positive mode at a compensation voltage of Vc=−26V. The main propene related peak in the negative mode is at a compensation voltage of Vc=−31V. When a sample of 100 ppm NO2+20 ppm NO is introduced into the DMS,
FIG. 9 , the positive ion propene peak remains at Vc=−26V while the negative ion peak shifts to a compensation voltage of Vc=−11 volts. This peak is the same as the one observed for the NO2 sample. From mass spectrometric analysis this peak has been determined to be an NO3 related peak. Once again, the negative mode DMS spectra shows a characteristic response for the total NOx sample. - Mass Spectrometric Investigation of DMS Spectral Peaks
- Analysis of the DMS spectra with NOx species shows that there are many possible pathways for formation of these ions in air, especially at ambient pressure. Spectra can contain derivative peaks of new species which are formed due to association, dissociation, fragmentation, oxidation and chemical reaction between molecules, fragments, and atmospheric gases. Therefore, validation experiments with direct chemical identification have been provided. For this purpose mass-spectrometric has been carried out.
FIG. 0 shows a schematic of a preferred micromachined DMS coupled to a mass spectrometer.1A - A photo-ionization source was attached to the DMS sensor for ionization, and a Teflon base was interfaced to pneumatically attach the DMS to the flange of a TAGA 6000 APCI-tandem mass spectrometer (MS/MS) from Sciex, Inc. (Toronto, Ontario, Canada). The MS/MS was equipped with a computer and API Standard Software, Ver 2.5.1 (PE SCIEX). Analytes (NOx) were introduced with transport gas and ionized before introduction into ion filter region of the DMS. Once through the filter region, the ions were injected through a hole in the detector electrode, into the pinhole of the interface plate of the MS/MS. Polarity of injected MS ions could be changed by changing the polarity of the deflector electrode. The significant advantage of this interface is that, under the effect of the deflector voltage and mass-spectrometer plenum gas, the analyzed ions are completely isolated from analyte neutrals exhausted by the DMS transport gas. Another advantage of this interface is the possibility to simultaneously record DMS and MS spectra.
-
FIG. 11 shows positive ion mass spectra for 20 ppm NO in dry N2,FIG. 11 a, andFIG. 11 b, when 10% of oxygen was added to the dry transport gas (N2). When instead, NO the NO2 samples were introduced mass-spectra similar to that ofFIG. 11 was recorded. One can see that the NO mass-spectra contains two series of ions: related to monomer and cluster nitric oxide ions WnNO+ and proton bounded water ions Wk H+. The level of water (W) clustering depends on the moisture level. For dry conditions, with humidity less than 10 ppm; the values of n and k may vary from 0 to 4. The nitric oxide peaks are M/z=30[NO+], 48[(W)NO+], 66[(W)2NO+], 84[(W)3NO+], 102[(W)4NO+], and proton bound water peaks are M/z=19[W.H+], 37 [(W)2H+]; 55[(W)3H+]; 73[(W)4H4 +]. - When humidity is higher, the level of clustering increases (see
FIG. 11 c). As a result the light nitric oxide monomer (m/z=30) and cluster (m/z=48) peaks disappear and heavier ions related to NO samples appear: 120[(W)5NO+]; 138[(W)6NO+]; 156[(W)7NO+]; 174[(W)8NO+]; 192[(W)9NO+]; and 204[(W)4NO+]2. Likewise, heavier water clusters also appear: 91[W5H+]; 109[W6H+]; 127[W7H+]; 145[W8H+]; 163[W9H+];181[W10H+]; 199[W11H+]. - The nitrogen dioxide and nitric oxide positive ions mass spectra are significantly different. In contrast to NO, the nitrogen dioxide positive ion mass spectra (
FIG. 11 b) shows no specific peaks related to NO2[m/z=46]. The mass-spectrum contains mostly proton bound water cluster ions m/z=37,55,73,91, relatively low intensity peak m/z=30 [NO+], and m/z=102 [W4NO+]. The last two peaks show that a process of dissociation of NO2 molecules to NO+O certainly exists. This is likely key to considering future oxidizing of NO2 molecules to NO3 by a series of chemical reaction steps (see, e.g. reactions (1)). The negative ion mass spectra for both samples, provides additional evidence for this mechanism. Mass spectra for both NO and NO2 samples are similar and contain peaks m/z=62, 125, 188 with the same peaks intensity relationship (FIG. 1A 2). - It is likely that these ions are NO3 −, (HNO3) NO3 −, and (HNO3)2 NO3 − which are formed as a result of oxidization (or solvating) of NO and NO2 to NO3 (or HNO3). The humidity effect on the negative ion mass-spectra is smaller than on the positive ions. At elevated moisture conditions the major peaks are the same as for dry conditions m/z=62, 125, 188, but several new cluster peaks at significantly increased mass (Δm=18) also appeared (207, 225, 243, 261, etc.). From the mass spectra experiments it is obvious that water chemistry plays a very significant role in NOx ion formation, especially in the positive polarity. With increased moisture new cluster ions appear and as a result specific sample ion peak intensities decrease, due to the increased number of proton bounded water ions. (This may be an explanation for the suppression of conventional IMS response.)
- According table I the photoionization source could not directly provide ionization of water molecules. A mechanism to explain formation of proton bounded water ions may be described by the following sequence of gas phase reactions:
NO+hv→NO++e−
NO++W+M→W NO++M
W NO++W+M→W2NO++M
Wn-1NO++W+M→WnNO++M, (3)
where M is a non-reacting molecule, generally N2. - When the water cluster around the NO+ is sufficiently large, its proton affinity becomes sufficient for reaction to become exothermic. Theoretical calculations show that this occurs for n=3, i.e. W3NO+ is the critical size for the switch from NO+ chemistry to protonated water chemistry.
W3NO++W→HNO2+W3H+ (4)
The peak at m/z 102 in the NOx mass-spectra 2 may be explained by this mechanism and may be the W4NO+ ion.
Evaluation of Memory Effects on Measurement Precision and Accuracy - In practice of the invention, memory effects were not a significant problem even though most characterization work was performed at room temperature. Furthermore, in real-world application, the gas temperature will be at least 100 C, which will reduce or eliminate any memory effects should they occur.
- Based upon the foregoing, it will be understood that we have shown highlights of the preferred practice of the present invention. Some of the highlights in practice of an illustrative embodiment of the invention include: NO samples are shown to produce a spectra containing only positive ion peaks. As expected there are no negative ions produced. NO2 samples produce spectra containing a number of low intensity peaks in the positive mode (including a peak with the same compensation voltage as observed with the pure NO sample) and one major peak in the negative polarity mode. The NO spectra, even at room temperature in the presence of oxygen, is transformed into a spectrum representative of the NO2 sample. Concentration dependence of NO and NO2 samples have different approximations: NO has linear and NO2 has quadratic approximation.
- The estimated limit of detection for both species is around 1 ppm. Even in the presence of interferants, the negative ion spectra is stable and provides sufficient accuracy for NOx monitoring under real world conditions.
- Mass spectrometric analysis of the positive and negative DMS spectra show that positive mode DMS peaks are mostly related to derivatives of NO+ and protonated water ions. In the negative mode, the DMS peak contains ions of NO3 − and its derivatives, which are oxidation products of NO and NO2. The formation of ions observed in the mass spectra are consistent with known chemistry but it must be emphasized that the systems are complex and there may be different channels (pathways) of ions formation which can explain obtained DMS/MS spectra.
- It will now be appreciated that the present invention provides direct measurement of NOx, including NO and NO2. High spectrometer sensitivity and ability to resolve NOx samples in real-time, even those not separated in conventional TOF-IMS, has been demonstrated. Further applications include an all-in-one detector that can make measurement of both hydrocarbon and NOx content in a gas sample in real-time. Thus such embodiment enables the realization of fast, miniature, low cost, high sensitivity, high reliability chemical detectors for detection of NOx and even of hydrocarbons in a gas sample, simultaneously.
- Furthermore, the present invention enables a compact system for other detection needs, such as detection of NO in exhaled breath for monitoring and treatment of medical conditions. The present invention therefore has applications to these and other medical treatments as will be apparent to a person skilled in the art.
- Therefore it will now be understood that the present invention discloses improved method and apparatus for gas sample analysis. Apparatus of the invention may feature planar, cylindrical, radial, or other DMS topologies and configurations. A preferred DMS embodiment of the invention enables a practical, small, fast (<100 msec), non-radioactive, sensitive and selective detector for real time monitoring of NOx.
- The examples and embodiments disclosed herein are shown by way of illustration and not by way of limitation. The scope of these and other embodiments is limited only as set forth in the following claims.
Claims (2)
Priority Applications (1)
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US10/981,001 US20050092914A1 (en) | 2002-10-12 | 2004-11-04 | NOx monitor using differential mobility spectrometry |
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US41823502P | 2002-10-12 | 2002-10-12 | |
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US10/981,001 US20050092914A1 (en) | 2002-10-12 | 2004-11-04 | NOx monitor using differential mobility spectrometry |
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US6815669B1 (en) * | 1999-07-21 | 2004-11-09 | The Charles Stark Draper Laboratory, Inc. | Longitudinal field driven ion mobility filter and detection system |
US7399958B2 (en) * | 1999-07-21 | 2008-07-15 | Sionex Corporation | Method and apparatus for enhanced ion mobility based sample analysis using various analyzer configurations |
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JP2008041345A (en) * | 2006-08-03 | 2008-02-21 | Fujitsu Ltd | Method of evaluating spot type ionizer, and spot type ionizer |
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Citations (40)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2615135A (en) * | 1950-06-20 | 1952-10-21 | Jr William E Glenn | Mass analyzing apparatus |
US3511986A (en) * | 1966-07-21 | 1970-05-12 | Varian Associates | Ion cyclotron double resonance spectrometer employing resonance in the ion source and analyzer |
US3619605A (en) * | 1969-06-25 | 1971-11-09 | Phillips Petroleum Co | Mass spectrometer method and apparatus employing high energy metastable ions to generate sample ions |
US3621240A (en) * | 1969-05-27 | 1971-11-16 | Franklin Gro Corp | Apparatus and methods for detecting and identifying trace gases |
US3931589A (en) * | 1974-03-21 | 1976-01-06 | The United States Of America As Represented By The Secretary Of The Navy | Perforated wall hollow-cathode ion laser |
US4025818A (en) * | 1976-04-20 | 1977-05-24 | Hughes Aircraft Company | Wire ion plasma electron gun |
US4163151A (en) * | 1977-12-28 | 1979-07-31 | Hughes Aircraft Company | Separated ion source |
US4201921A (en) * | 1978-07-24 | 1980-05-06 | International Business Machines Corporation | Electron beam-capillary plasma flash x-ray device |
US5092157A (en) * | 1987-07-08 | 1992-03-03 | Thermedics Inc. | Vapor collector/desorber with metallic ribbon |
US5144127A (en) * | 1991-08-02 | 1992-09-01 | Williams Evan R | Surface induced dissociation with reflectron time-of-flight mass spectrometry |
US5218203A (en) * | 1991-03-22 | 1993-06-08 | Georgia Tech Research Corporation | Ion source and sample introduction method and apparatus using two stage ionization for producing sample gas ions |
US5420424A (en) * | 1994-04-29 | 1995-05-30 | Mine Safety Appliances Company | Ion mobility spectrometer |
US5455417A (en) * | 1994-05-05 | 1995-10-03 | Sacristan; Emilio | Ion mobility method and device for gas analysis |
US5536939A (en) * | 1993-09-22 | 1996-07-16 | Northrop Grumman Corporation | Miniaturized mass filter |
US5654544A (en) * | 1995-08-10 | 1997-08-05 | Analytica Of Branford | Mass resolution by angular alignment of the ion detector conversion surface in time-of-flight mass spectrometers with electrostatic steering deflectors |
US5723861A (en) * | 1996-04-04 | 1998-03-03 | Mine Safety Appliances Company | Recirculating filtration system for use with a transportable ion mobility spectrometer |
US5763876A (en) * | 1996-04-04 | 1998-06-09 | Mine Safety Appliances Company | Inlet heating device for ion mobility spectrometer |
US5789745A (en) * | 1997-10-28 | 1998-08-04 | Sandia Corporation | Ion mobility spectrometer using frequency-domain separation |
US5801379A (en) * | 1996-03-01 | 1998-09-01 | Mine Safety Appliances Company | High voltage waveform generator |
US5834771A (en) * | 1994-07-08 | 1998-11-10 | Agency For Defence Development | Ion mobility spectrometer utilizing flexible printed circuit board and method for manufacturing thereof |
US5838003A (en) * | 1996-09-27 | 1998-11-17 | Hewlett-Packard Company | Ionization chamber and mass spectrometry system containing an asymmetric electrode |
US5965882A (en) * | 1997-10-07 | 1999-10-12 | Raytheon Company | Miniaturized ion mobility spectrometer sensor cell |
US6066848A (en) * | 1998-06-09 | 2000-05-23 | Combichem, Inc. | Parallel fluid electrospray mass spectrometer |
US6124592A (en) * | 1998-03-18 | 2000-09-26 | Technispan Llc | Ion mobility storage trap and method |
US20010030285A1 (en) * | 1999-07-21 | 2001-10-18 | Miller Raanan A. | Method and apparatus for chromatography-high field asymmetric waveform Ion mobility spectrometry |
US6323482B1 (en) * | 1997-06-02 | 2001-11-27 | Advanced Research And Technology Institute, Inc. | Ion mobility and mass spectrometer |
US20020070338A1 (en) * | 2000-12-08 | 2002-06-13 | Loboda Alexander V. | Ion mobility spectrometer incorporating an ion guide in combination with an MS device |
US20020134932A1 (en) * | 1998-08-05 | 2002-09-26 | Roger Guevremont | Apparatus and method for desolvating and focussing ions for introduction into a mass spectrometer |
US6495823B1 (en) * | 1999-07-21 | 2002-12-17 | The Charles Stark Draper Laboratory, Inc. | Micromachined field asymmetric ion mobility filter and detection system |
US6512224B1 (en) * | 1999-07-21 | 2003-01-28 | The Charles Stark Draper Laboratory, Inc. | Longitudinal field driven field asymmetric ion mobility filter and detection system |
US20030020012A1 (en) * | 2000-03-14 | 2003-01-30 | Roger Guevremont | Tandem high field asymmetric waveform ion mobility spectrometry (faims)tandem mass spectrometry |
US20030052263A1 (en) * | 2001-06-30 | 2003-03-20 | Sionex Corporation | System for collection of data and identification of unknown ion species in an electric field |
US20030089847A1 (en) * | 2000-03-14 | 2003-05-15 | Roger Guevremont | Tandem high field asymmetric waveform ion mobility spectrometry ( faims)/ion mobility spectrometry |
US20030132380A1 (en) * | 1999-07-21 | 2003-07-17 | Sionex Corporation | Micromachined field asymmetric ion mobility filter and detection system |
US6621077B1 (en) * | 1998-08-05 | 2003-09-16 | National Research Council Canada | Apparatus and method for atmospheric pressure-3-dimensional ion trapping |
US6690004B2 (en) * | 1999-07-21 | 2004-02-10 | The Charles Stark Draper Laboratory, Inc. | Method and apparatus for electrospray-augmented high field asymmetric ion mobility spectrometry |
US6713758B2 (en) * | 1998-08-05 | 2004-03-30 | National Research Council Of Canada | Spherical side-to-side FAIMS |
US6753522B2 (en) * | 2002-02-08 | 2004-06-22 | Ionalytics Corporation | FAIMS apparatus having plural ion inlets and method therefore |
US20050029449A1 (en) * | 1999-07-21 | 2005-02-10 | Miller Raanan A. | System for trajectory-based ion species identification |
US20050056780A1 (en) * | 2003-09-17 | 2005-03-17 | Sionex Corporation | Solid-state gas flow generator and related systems, applications, and methods |
Family Cites Families (14)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US500004A (en) * | 1893-06-20 | Fence-building machine | ||
SU966583A1 (en) | 1980-03-10 | 1982-10-15 | Предприятие П/Я А-1342 | Method of analysis of impurities in gases |
SU1337934A2 (en) | 1986-04-09 | 1987-09-15 | Предприятие П/Я А-1882 | Method of analysis of impurities in gases |
SU1412447A1 (en) | 1986-11-03 | 1998-06-20 | И.А. Буряков | Drift spectrometer to detect microimpurities of substances in gases |
SU1485808A1 (en) | 1987-03-30 | 1998-06-10 | И.А. Буряков | Method of analyzing traces of substances in gases |
SU1627984A2 (en) | 1988-07-20 | 1991-02-15 | Предприятие П/Я А-1882 | Method of gas analysis for impurities |
GB2296369A (en) | 1994-12-22 | 1996-06-26 | Secr Defence | Radio frequency ion source |
WO2000008457A1 (en) | 1998-08-05 | 2000-02-17 | National Research Council Canada | Apparatus and method for atmospheric pressure 3-dimensional ion trapping |
WO2001022049A2 (en) | 1999-09-24 | 2001-03-29 | Haley Lawrence V | A novel ion-mobility based device using an oscillatory high-field ion separator with a multi-channel array charge collector |
US6417511B1 (en) * | 2000-07-17 | 2002-07-09 | Agilent Technologies, Inc. | Ring pole ion guide apparatus, systems and method |
WO2002083276A1 (en) | 2001-04-17 | 2002-10-24 | The Charles Stark Draper Laboratory, Inc. | Methods and apparatus for electrospray-augmented high field asymmetric ion mobility spectrometry |
US6599253B1 (en) * | 2001-06-25 | 2003-07-29 | Oak Crest Institute Of Science | Non-invasive, miniature, breath monitoring apparatus |
US7274015B2 (en) * | 2001-08-08 | 2007-09-25 | Sionex Corporation | Capacitive discharge plasma ion source |
US7034286B2 (en) | 2002-02-08 | 2006-04-25 | Ionalytics Corporation | FAIMS apparatus having plural ion inlets and method therefore |
-
2003
- 2003-10-10 US US10/684,332 patent/US7019291B2/en not_active Expired - Lifetime
- 2003-10-10 AU AU2003298597A patent/AU2003298597A1/en not_active Abandoned
- 2003-10-10 WO PCT/US2003/032244 patent/WO2004040257A2/en not_active Application Discontinuation
-
2004
- 2004-11-04 US US10/981,001 patent/US20050092914A1/en not_active Abandoned
Patent Citations (49)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2615135A (en) * | 1950-06-20 | 1952-10-21 | Jr William E Glenn | Mass analyzing apparatus |
US3511986A (en) * | 1966-07-21 | 1970-05-12 | Varian Associates | Ion cyclotron double resonance spectrometer employing resonance in the ion source and analyzer |
US3621240A (en) * | 1969-05-27 | 1971-11-16 | Franklin Gro Corp | Apparatus and methods for detecting and identifying trace gases |
US3619605A (en) * | 1969-06-25 | 1971-11-09 | Phillips Petroleum Co | Mass spectrometer method and apparatus employing high energy metastable ions to generate sample ions |
US3931589A (en) * | 1974-03-21 | 1976-01-06 | The United States Of America As Represented By The Secretary Of The Navy | Perforated wall hollow-cathode ion laser |
US4025818A (en) * | 1976-04-20 | 1977-05-24 | Hughes Aircraft Company | Wire ion plasma electron gun |
US4163151A (en) * | 1977-12-28 | 1979-07-31 | Hughes Aircraft Company | Separated ion source |
US4201921A (en) * | 1978-07-24 | 1980-05-06 | International Business Machines Corporation | Electron beam-capillary plasma flash x-ray device |
US5092157A (en) * | 1987-07-08 | 1992-03-03 | Thermedics Inc. | Vapor collector/desorber with metallic ribbon |
US5218203A (en) * | 1991-03-22 | 1993-06-08 | Georgia Tech Research Corporation | Ion source and sample introduction method and apparatus using two stage ionization for producing sample gas ions |
US5144127A (en) * | 1991-08-02 | 1992-09-01 | Williams Evan R | Surface induced dissociation with reflectron time-of-flight mass spectrometry |
US5536939A (en) * | 1993-09-22 | 1996-07-16 | Northrop Grumman Corporation | Miniaturized mass filter |
US5420424A (en) * | 1994-04-29 | 1995-05-30 | Mine Safety Appliances Company | Ion mobility spectrometer |
US5455417A (en) * | 1994-05-05 | 1995-10-03 | Sacristan; Emilio | Ion mobility method and device for gas analysis |
US5834771A (en) * | 1994-07-08 | 1998-11-10 | Agency For Defence Development | Ion mobility spectrometer utilizing flexible printed circuit board and method for manufacturing thereof |
US5654544A (en) * | 1995-08-10 | 1997-08-05 | Analytica Of Branford | Mass resolution by angular alignment of the ion detector conversion surface in time-of-flight mass spectrometers with electrostatic steering deflectors |
US5801379A (en) * | 1996-03-01 | 1998-09-01 | Mine Safety Appliances Company | High voltage waveform generator |
US5723861A (en) * | 1996-04-04 | 1998-03-03 | Mine Safety Appliances Company | Recirculating filtration system for use with a transportable ion mobility spectrometer |
US5763876A (en) * | 1996-04-04 | 1998-06-09 | Mine Safety Appliances Company | Inlet heating device for ion mobility spectrometer |
US5838003A (en) * | 1996-09-27 | 1998-11-17 | Hewlett-Packard Company | Ionization chamber and mass spectrometry system containing an asymmetric electrode |
US6323482B1 (en) * | 1997-06-02 | 2001-11-27 | Advanced Research And Technology Institute, Inc. | Ion mobility and mass spectrometer |
US5965882A (en) * | 1997-10-07 | 1999-10-12 | Raytheon Company | Miniaturized ion mobility spectrometer sensor cell |
US5789745A (en) * | 1997-10-28 | 1998-08-04 | Sandia Corporation | Ion mobility spectrometer using frequency-domain separation |
US6124592A (en) * | 1998-03-18 | 2000-09-26 | Technispan Llc | Ion mobility storage trap and method |
US6066848A (en) * | 1998-06-09 | 2000-05-23 | Combichem, Inc. | Parallel fluid electrospray mass spectrometer |
US6621077B1 (en) * | 1998-08-05 | 2003-09-16 | National Research Council Canada | Apparatus and method for atmospheric pressure-3-dimensional ion trapping |
US6639212B1 (en) * | 1998-08-05 | 2003-10-28 | National Research Council Canada | Method for separation of isomers and different conformations of ions in gaseous phase |
US20020134932A1 (en) * | 1998-08-05 | 2002-09-26 | Roger Guevremont | Apparatus and method for desolvating and focussing ions for introduction into a mass spectrometer |
US6770875B1 (en) * | 1998-08-05 | 2004-08-03 | National Research Council Canada | Apparatus and method for desolvating and focussing ions for introduction into a mass spectrometer |
US6504149B2 (en) * | 1998-08-05 | 2003-01-07 | National Research Council Canada | Apparatus and method for desolvating and focussing ions for introduction into a mass spectrometer |
US6713758B2 (en) * | 1998-08-05 | 2004-03-30 | National Research Council Of Canada | Spherical side-to-side FAIMS |
US20010030285A1 (en) * | 1999-07-21 | 2001-10-18 | Miller Raanan A. | Method and apparatus for chromatography-high field asymmetric waveform Ion mobility spectrometry |
US6690004B2 (en) * | 1999-07-21 | 2004-02-10 | The Charles Stark Draper Laboratory, Inc. | Method and apparatus for electrospray-augmented high field asymmetric ion mobility spectrometry |
US20050029449A1 (en) * | 1999-07-21 | 2005-02-10 | Miller Raanan A. | System for trajectory-based ion species identification |
US6495823B1 (en) * | 1999-07-21 | 2002-12-17 | The Charles Stark Draper Laboratory, Inc. | Micromachined field asymmetric ion mobility filter and detection system |
US20030132380A1 (en) * | 1999-07-21 | 2003-07-17 | Sionex Corporation | Micromachined field asymmetric ion mobility filter and detection system |
US6512224B1 (en) * | 1999-07-21 | 2003-01-28 | The Charles Stark Draper Laboratory, Inc. | Longitudinal field driven field asymmetric ion mobility filter and detection system |
US6774360B2 (en) * | 2000-03-14 | 2004-08-10 | National Research Council Canada | FAIMS apparatus and method using carrier gas of mixed composition |
US6653627B2 (en) * | 2000-03-14 | 2003-11-25 | National Research Council Canada | FAIMS apparatus and method with laser-based ionization source |
US20030020012A1 (en) * | 2000-03-14 | 2003-01-30 | Roger Guevremont | Tandem high field asymmetric waveform ion mobility spectrometry (faims)tandem mass spectrometry |
US6703609B2 (en) * | 2000-03-14 | 2004-03-09 | National Research Council Canada | Tandem FAIMS/ion-trapping apparatus and method |
US20030089847A1 (en) * | 2000-03-14 | 2003-05-15 | Roger Guevremont | Tandem high field asymmetric waveform ion mobility spectrometry ( faims)/ion mobility spectrometry |
US20030038235A1 (en) * | 2000-03-14 | 2003-02-27 | Roger Guevremont | Tandem faims/ion-trapping apparatus and method |
US6799355B2 (en) * | 2000-03-14 | 2004-10-05 | National Research Council Canada | Apparatus and method for tandem ICP/FAIMS/MS |
US20020070338A1 (en) * | 2000-12-08 | 2002-06-13 | Loboda Alexander V. | Ion mobility spectrometer incorporating an ion guide in combination with an MS device |
US20030052263A1 (en) * | 2001-06-30 | 2003-03-20 | Sionex Corporation | System for collection of data and identification of unknown ion species in an electric field |
US6753522B2 (en) * | 2002-02-08 | 2004-06-22 | Ionalytics Corporation | FAIMS apparatus having plural ion inlets and method therefore |
US6787765B2 (en) * | 2002-02-08 | 2004-09-07 | Ionalytics Corporation | FAIMS with non-destructive detection of selectively transmitted ions |
US20050056780A1 (en) * | 2003-09-17 | 2005-03-17 | Sionex Corporation | Solid-state gas flow generator and related systems, applications, and methods |
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US8904849B2 (en) | 2006-09-28 | 2014-12-09 | Smiths Detection Inc. | Multi-detector gas identification system |
WO2008039996A3 (en) * | 2006-09-28 | 2008-07-03 | Smiths Detection Inc | Multi-detector gas identification system |
US7963146B2 (en) | 2007-05-14 | 2011-06-21 | General Dynamics Armament And Technical Products, Inc. | Method and system for detecting vapors |
CN106841372A (en) * | 2015-12-07 | 2017-06-13 | 中国科学院大连化学物理研究所 | It is a kind of to monitor NO in air simultaneouslyX、O3And SO2Method |
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US11760169B2 (en) | 2020-08-20 | 2023-09-19 | Denso International America, Inc. | Particulate control systems and methods for olfaction sensors |
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US11881093B2 (en) | 2020-08-20 | 2024-01-23 | Denso International America, Inc. | Systems and methods for identifying smoking in vehicles |
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WO2004040257A2 (en) | 2004-05-13 |
US20040136872A1 (en) | 2004-07-15 |
US7019291B2 (en) | 2006-03-28 |
AU2003298597A8 (en) | 2004-05-25 |
AU2003298597A1 (en) | 2004-05-25 |
WO2004040257A3 (en) | 2005-02-24 |
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