It relates to a chemical analysis system (10). In this system, with a RF driving plasma ionizer (... more It relates to a chemical analysis system (10). In this system, with a RF driving plasma ionizer (11) is shielded from the plasma spaced a pair of electrodes (14, 16). These electrodes (14, 16) is connected to a power source (22), electrodes (14, 16) acts as a plate of the capacitor of the resonant circuit (22c), the positive gas (S) is electrically discharged generating a plasma of both ions and negative ions. Voltage is applied as a series of pulses as a continuous alternating waveform or packet waveform.
Mass spectrometry is an analytical technique widely used in the scientific community to determine... more Mass spectrometry is an analytical technique widely used in the scientific community to determine chemical composition of sample compounds. Typically, mass spectrometers perform their analysis under vacuum conditions, though atmospheric pressure mass spectrometers are becoming more prevalent. With the development of atmospheric pressure mass spectrometers, techniques such as FAIMS (Field Asymmetric Ion Mobility Spectrometry) have emerged; which achieve higher transfer efficiency into the mass spectrometer and thus improve the instrument's sensitivity. Ion behavior in higher pressure conditions, such as in ambient ionization sources, is less understood, thus making it more difficult to predict ion trajectories and concentrations. Modeling of this ion behavior becomes challenging, due to concurrent effects of fluid flow and diffusion in addition to dynamically changing electric fields. These non-linear parameters are however, more easily employed in current software iterations. Io...
A high electric field, radio-frequency ion mobility spectrometry (RF-IMS) analyzer was used as a ... more A high electric field, radio-frequency ion mobility spectrometry (RF-IMS) analyzer was used as a small detector in gas chromatographic separations of mixtures of volatile organic compounds including alcohols, aldehydes, esters, ethers, pheromones, and other chemical attractants for insects. The detector was equipped with a 2 mCi 63Ni ion source and the drift region for ion characterization was 5 mm wide, 15 mm long and 0.5 mm high. The rate of scanning for the compensation voltages was 60 V s(-1) and permitted four to six scans to be obtained across a capillary chromatographic elution profile for each component. The RF-IMS scans were characteristic of a compound and provided a second dimension of chemical identity to chromatographic retention adding specificity in instances of co-elution. Limits of detection were 1.6-55 x 10(-11) g with an average detection limit for all chemicals of 9.4 x 10(-11) g. Response to mass was linear from 2-50 x 10(-10) g with an average sensitivity of 4 pA ng(-1). Separations of pheromones and chemical attractants for insects illustrated the distinct patterns obtained from gas chromatography with RF-IMS scans in real time and suggest an analytical utility of the RF-IMS as a small, advanced detector for on-site gas chromatographs.
International Journal for Ion Mobility Spectrometry
In-flight monitoring of volatile organic compounds on the International Space Station (ISS) has b... more In-flight monitoring of volatile organic compounds on the International Space Station (ISS) has been routine since 2009 using gas chromatography, with a preconcentration inlet, and a differential mobility spectrometer detector; first as a station detailed technical objective (SDTO) instrument and then as the air quality monitor (AQM), a fully integrated instrument including imbedded computer for control and data acquisition. A combination of AQM with an atmospheric pressure ionization mass spectrometer was developed to allow exploration of instrument behavior associated with the composition of the internal recirculated gas atmosphere. The first aspects of AQM to be explored using the AQM-mass spectrometer included explanations for mobility drift of the negative reactant ion peak, methanol, and acetaldyehyde peaks (carbon dioxide in the gas recirculation loop) with operation on ISS. The AQM-mass spectrometer system helped ascertain the identity of artifact peaks in the negative polarity associated with materials in the flow system of AQM. Further experiments investigated the influence of water from humidity in ambient air, which is absorbed on the preconcentration trap during sampling and desorbed into the gas chromatograph-differential mobility spectrometer (GC-DMS) measurement and the incorporation of a trap purge to reduce effects of water co-eluting with target contaminants.
The micromachined Planar High Field Asymmetric Waveform Ion Mobility Spectrometer (PFAIMS) is a n... more The micromachined Planar High Field Asymmetric Waveform Ion Mobility Spectrometer (PFAIMS) is a novel detector for chemical and biological sensing applications. This detector fills an unmet market need, providing spectrometer capabilities and extremely high sensitivity, at a cost comparable to stand-alone sensors. The PFAIMS is quantitative, and has detection limits down to the parts-per-trillion. The performance of the PFAIMS in a number of applications ranging from industrial to biomedical, where it is used as both a stand alone sensor, and as a gas chromatographic detector are demonstrated. These applications include the detection of xylene isomers and non-invasive medical diagnosis through breath analysis.
TRANSDUCERS '03. 12th International Conference on Solid-State Sensors, Actuators and Microsystems. Digest of Technical Papers (Cat. No.03TH8664), 2000
... The pyrolyzer is capable of heating samples from room temperature to 1400°C at rates from I t... more ... The pyrolyzer is capable of heating samples from room temperature to 1400°C at rates from I to 20"Cis. ... The-peak width at half height averages 1.4 V. It is known that pyrolysis is capable of fully decarboxylating DPA to pyridine. ...
Mobility spectra for positive ions, created from a 63Ni foil in purified air at ambient pressure ... more Mobility spectra for positive ions, created from a 63Ni foil in purified air at ambient pressure (660 Torr) with 0.15 ppm moisture, were obtained with a drift tube with a discrete drift ring design at 250 °C as electric fields for components were individually and independently varied. Peak area, peak width, baseline intensity, drift times, and reduced mobilities (Ko) were used to measure the function and performance of each component and findings were interpreted using a model for the transport of thermalized ions in weak electric fields at ambient pressure. Transit times and intensities for ions in drift tubes at ambient pressure can be understood through a detailed knowledge of the fields local to a component and derivations from theory of ion transport. Prolonged ion residence in the drift region resulted in ion transformations even for highly purified gases of low moisture at high temperature. These findings suggest that mobility spectra may be obtained with uniformly high quality and reproducibility only under conditions when ion residence time is the primary point of reference in obtaining spectra. Other regions of the drift tube were optimized and newly observed chemistry occurred in the aperture to detector region. The sampling of ions by such an ion shutter was found to inherently bias the ion distributions and alter actual lengths of drift regions. Consequently, drift lengths measured from physical configurations of drift tubes will be inadequate for precise measurements of drift times. These studies establish baseline measurements for evaluating drift tubes that should be generally applicable for optimizing performance in other drift tubes with discrete drift ring designs. Also, these results demonstrate that precise measurements in ion mobility spectrometry (IMS) will require attention to detail not heretofore carefully regarded in modern analytical IMS.
International journal for ion mobility spectrometry : official publication of the International Society for Ion Mobility Spectrometry, 2012
Clinical and forensic toxicology laboratories are inundated with thousands of samples requiring l... more Clinical and forensic toxicology laboratories are inundated with thousands of samples requiring lengthy chromatographic separations prior to mass spectrometry. Here, we employ differential mobility spectrometry (DMS) interfaced to nano-electrospray ionization-mass spectrometry to provide a rapid ion filtration technique for the separation of ions in gas phase media prior to mass spectral analysis on a DMS-integrated AB SCIEX API 3000 triple-quadrupole mass spectrometer. DMS is efficient at the rapid separation of ions under ambient conditions and provides many advantages when used as an ion filtration technique in tandem with mass spectrometry (MS) and MS/MS. Our studies evaluated DMS-MS/MS as a rapid, quantitative platform for the analysis of drug metabolites isolated from urine samples. In targeted applications, five metabolites of common drugs of abuse were effectively and rapidly separated using isopropanol and ethyl acetate as transport gas modifiers, eliminating the gas chroma...
It relates to a chemical analysis system (10). In this system, with a RF driving plasma ionizer (... more It relates to a chemical analysis system (10). In this system, with a RF driving plasma ionizer (11) is shielded from the plasma spaced a pair of electrodes (14, 16). These electrodes (14, 16) is connected to a power source (22), electrodes (14, 16) acts as a plate of the capacitor of the resonant circuit (22c), the positive gas (S) is electrically discharged generating a plasma of both ions and negative ions. Voltage is applied as a series of pulses as a continuous alternating waveform or packet waveform.
Mass spectrometry is an analytical technique widely used in the scientific community to determine... more Mass spectrometry is an analytical technique widely used in the scientific community to determine chemical composition of sample compounds. Typically, mass spectrometers perform their analysis under vacuum conditions, though atmospheric pressure mass spectrometers are becoming more prevalent. With the development of atmospheric pressure mass spectrometers, techniques such as FAIMS (Field Asymmetric Ion Mobility Spectrometry) have emerged; which achieve higher transfer efficiency into the mass spectrometer and thus improve the instrument's sensitivity. Ion behavior in higher pressure conditions, such as in ambient ionization sources, is less understood, thus making it more difficult to predict ion trajectories and concentrations. Modeling of this ion behavior becomes challenging, due to concurrent effects of fluid flow and diffusion in addition to dynamically changing electric fields. These non-linear parameters are however, more easily employed in current software iterations. Io...
A high electric field, radio-frequency ion mobility spectrometry (RF-IMS) analyzer was used as a ... more A high electric field, radio-frequency ion mobility spectrometry (RF-IMS) analyzer was used as a small detector in gas chromatographic separations of mixtures of volatile organic compounds including alcohols, aldehydes, esters, ethers, pheromones, and other chemical attractants for insects. The detector was equipped with a 2 mCi 63Ni ion source and the drift region for ion characterization was 5 mm wide, 15 mm long and 0.5 mm high. The rate of scanning for the compensation voltages was 60 V s(-1) and permitted four to six scans to be obtained across a capillary chromatographic elution profile for each component. The RF-IMS scans were characteristic of a compound and provided a second dimension of chemical identity to chromatographic retention adding specificity in instances of co-elution. Limits of detection were 1.6-55 x 10(-11) g with an average detection limit for all chemicals of 9.4 x 10(-11) g. Response to mass was linear from 2-50 x 10(-10) g with an average sensitivity of 4 pA ng(-1). Separations of pheromones and chemical attractants for insects illustrated the distinct patterns obtained from gas chromatography with RF-IMS scans in real time and suggest an analytical utility of the RF-IMS as a small, advanced detector for on-site gas chromatographs.
International Journal for Ion Mobility Spectrometry
In-flight monitoring of volatile organic compounds on the International Space Station (ISS) has b... more In-flight monitoring of volatile organic compounds on the International Space Station (ISS) has been routine since 2009 using gas chromatography, with a preconcentration inlet, and a differential mobility spectrometer detector; first as a station detailed technical objective (SDTO) instrument and then as the air quality monitor (AQM), a fully integrated instrument including imbedded computer for control and data acquisition. A combination of AQM with an atmospheric pressure ionization mass spectrometer was developed to allow exploration of instrument behavior associated with the composition of the internal recirculated gas atmosphere. The first aspects of AQM to be explored using the AQM-mass spectrometer included explanations for mobility drift of the negative reactant ion peak, methanol, and acetaldyehyde peaks (carbon dioxide in the gas recirculation loop) with operation on ISS. The AQM-mass spectrometer system helped ascertain the identity of artifact peaks in the negative polarity associated with materials in the flow system of AQM. Further experiments investigated the influence of water from humidity in ambient air, which is absorbed on the preconcentration trap during sampling and desorbed into the gas chromatograph-differential mobility spectrometer (GC-DMS) measurement and the incorporation of a trap purge to reduce effects of water co-eluting with target contaminants.
The micromachined Planar High Field Asymmetric Waveform Ion Mobility Spectrometer (PFAIMS) is a n... more The micromachined Planar High Field Asymmetric Waveform Ion Mobility Spectrometer (PFAIMS) is a novel detector for chemical and biological sensing applications. This detector fills an unmet market need, providing spectrometer capabilities and extremely high sensitivity, at a cost comparable to stand-alone sensors. The PFAIMS is quantitative, and has detection limits down to the parts-per-trillion. The performance of the PFAIMS in a number of applications ranging from industrial to biomedical, where it is used as both a stand alone sensor, and as a gas chromatographic detector are demonstrated. These applications include the detection of xylene isomers and non-invasive medical diagnosis through breath analysis.
TRANSDUCERS '03. 12th International Conference on Solid-State Sensors, Actuators and Microsystems. Digest of Technical Papers (Cat. No.03TH8664), 2000
... The pyrolyzer is capable of heating samples from room temperature to 1400°C at rates from I t... more ... The pyrolyzer is capable of heating samples from room temperature to 1400°C at rates from I to 20"Cis. ... The-peak width at half height averages 1.4 V. It is known that pyrolysis is capable of fully decarboxylating DPA to pyridine. ...
Mobility spectra for positive ions, created from a 63Ni foil in purified air at ambient pressure ... more Mobility spectra for positive ions, created from a 63Ni foil in purified air at ambient pressure (660 Torr) with 0.15 ppm moisture, were obtained with a drift tube with a discrete drift ring design at 250 °C as electric fields for components were individually and independently varied. Peak area, peak width, baseline intensity, drift times, and reduced mobilities (Ko) were used to measure the function and performance of each component and findings were interpreted using a model for the transport of thermalized ions in weak electric fields at ambient pressure. Transit times and intensities for ions in drift tubes at ambient pressure can be understood through a detailed knowledge of the fields local to a component and derivations from theory of ion transport. Prolonged ion residence in the drift region resulted in ion transformations even for highly purified gases of low moisture at high temperature. These findings suggest that mobility spectra may be obtained with uniformly high quality and reproducibility only under conditions when ion residence time is the primary point of reference in obtaining spectra. Other regions of the drift tube were optimized and newly observed chemistry occurred in the aperture to detector region. The sampling of ions by such an ion shutter was found to inherently bias the ion distributions and alter actual lengths of drift regions. Consequently, drift lengths measured from physical configurations of drift tubes will be inadequate for precise measurements of drift times. These studies establish baseline measurements for evaluating drift tubes that should be generally applicable for optimizing performance in other drift tubes with discrete drift ring designs. Also, these results demonstrate that precise measurements in ion mobility spectrometry (IMS) will require attention to detail not heretofore carefully regarded in modern analytical IMS.
International journal for ion mobility spectrometry : official publication of the International Society for Ion Mobility Spectrometry, 2012
Clinical and forensic toxicology laboratories are inundated with thousands of samples requiring l... more Clinical and forensic toxicology laboratories are inundated with thousands of samples requiring lengthy chromatographic separations prior to mass spectrometry. Here, we employ differential mobility spectrometry (DMS) interfaced to nano-electrospray ionization-mass spectrometry to provide a rapid ion filtration technique for the separation of ions in gas phase media prior to mass spectral analysis on a DMS-integrated AB SCIEX API 3000 triple-quadrupole mass spectrometer. DMS is efficient at the rapid separation of ions under ambient conditions and provides many advantages when used as an ion filtration technique in tandem with mass spectrometry (MS) and MS/MS. Our studies evaluated DMS-MS/MS as a rapid, quantitative platform for the analysis of drug metabolites isolated from urine samples. In targeted applications, five metabolites of common drugs of abuse were effectively and rapidly separated using isopropanol and ethyl acetate as transport gas modifiers, eliminating the gas chroma...
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Papers by E. Nazarov