Abstract: A method and apparatus that ionize vapors for their chemical analysis is described. The new ionizer improves the ionization efficiency by reducing dilution of sample molecules and improving transmission of ions to the analyzer. This is accomplished by a new flow configuration, in which a stream of clean gas focuses the ions towards the analyzer. A deflector prevents the formation of turbulent perturbation, and the ionization maintains a laminar regime without the need for additional separating walls or electrodes. The flow within the ionizer is configured so that contaminants released by the inner walls of the ionizer do not reach the ionization region. The resulting ionizer improves the ionization efficiency, and the background levels for low volatility species. This makes it ideal for the analysis of low volatility species in the gas phase. One application of this ionizer is the analysis of human breath in real time.

Abstract: A method and apparatus that ionize vapors for their chemical analysis is described. The new ionizer improves the ionization efficiency by reducing dilution of sample molecules and improving transmission of ions to the analyzer. This is accomplished by a new flow configuration, in which a stream of clean gas focuses the ions towards the analyzer. A deflector prevents the formation of turbulent perturbation, and the ionization maintains a laminar regime without the need for additional separating walls or electrodes. The flow within the ionizer is configured so that contaminants released by the inner walls of the ionizer do not reach the ionization region. The resulting ionizer improves the ionization efficiency, and the background levels for low volatility species. This makes it ideal for the analysis of low volatility species in the gas phase. One application of this ionizer is the analysis of human breath in real time.

Abstract: A method and apparatus that generate beams of ions with controlled ranges of mobility is described. Ions are introduced through an inlet in a channel. An axial electric field pushes the ions forward through said channel towards an outlet. The invention also incorporates regions in which ions are depleted, and which travel along said channel at a controlled velocity. These Regions are sequentially induced by locally applying a transversal electric field that deflects the ions away from the axis of said channel, or an axial field that pushes the ions backwards and deflects them away from said axis. Ions that travel at different velocity from the velocity of said regions eventually hit or are hit by said regions, and they do not reach the outlet, while ions of the selected mobility (which travel at the same velocity as said regions) travel through said channel unaltered and reach the outlet.

Abstract: Improvements are provided in the detection of atmospheric vapors by ionizing them near ambient pressure, and analyzing them as ions. Lowest detection limits of parts per quadrillion (ppq) concentrations are enabled by a combination of improvements, including the use of a filter to remove occasional intense signal from explosive particles. Several sources of chemical background are identified and solutions for their reduction or elimination are presented. Gains in response time may be achieved by operating at elevated temperature. When the ionizer is an electrospray source, the use of high boiling point solvents is indicated. An increased selectivity is achieved by operating a differential mobility analyzer (DMA) in series with a mass spectrometer. However, ppq sensitivities require various improvements in the DMA system including a special coupling to the ionizer, controlling the temperature in the DMA pump circuit, avoidance of induction on the DMA electrodes from heating devices, etc.

Abstract: A method and apparatus that operate at near atmospheric pressure are described to simultaneously (i) desolvate the droplets produced by an ions source (including electrospray sources), to (ii) separate the surviving droplets from the analyte ions, to (iii) increase the transmission of ions through the inlet of an analyzer, while (iv) preventing the passage through said inlet of neutral contaminants and low mobility species and droplets that could potentially impair the operation of the analyzer, which include mass spectrometers and ion mobility spectrometers. In the present invention, contaminant low mobility species are efficiently deflected away from the analyzer inlet by a sweep flow. The sweep flow is laminar, affects ions in a region immediately after they leave the ionizer, and provides a preliminary separation of species. Consequently, the dilution effect produced by coulombic repulsion is minimized, and thus, analyte ions pass through the analyzer inlet with a higher transmission.

Abstract: A method and an apparatus are described to improve the separation capacity of an ion analyzer incorporating at least two stages of ion mobility analysis. The new invention utilizes possible use of different mixtures of gases and dopants in each stage, control over different concentrations of gases and dopants in each stage, and allowance of passage of the selected ions from one stage to the next while avoiding the mixing of the gases and dopants among stages. The new invention also includes a method to reduce the time required to identify the physical properties in a set of ion filters where at least one of the filters is a scannable ion mobility analyzer. The present invention also includes how to provide a set of scannable ion mobility analyzers operating in series, wherein each stage can be operated as a filter, or allowing for the passage of all ions.

Abstract: A method and an apparatus are described to improve the separation capacity of an ion analyzer incorporating at least two stages of ion mobility analysis. The new invention utilizes possible use of different mixtures of gases and dopants in each stage, control over different concentrations of gases and dopants in each stage, and allowance of passage of the selected ions from one stage to the next while avoiding the mixing of the gases and dopants among stages. The new invention also includes a method to reduce the time required to identify the physical properties in a set of ion filters where at least one of the filters is a scannable ion mobility analyzer. The present invention also includes how to provide a set of scannable ion mobility analyzers operating in series, wherein each stage can be operated as a filter, or allowing for the passage of all ions.

Abstract: A method and apparatus are described to increase the efficiency with which a sample vapor is ionized prior to being introduced into an analyzer. Excellent contact between the vapor and the charging agent is achieved in the ionization chamber with a perforated impaction plate. As a result, some desired fraction of the gas going into, or coming out of the analyzer can be controlled independently from the flow of sample through the ionization chamber. Furthermore, penetration into the ionization chamber of the desired fraction of the gas is minimized by controlling the dimensions of the perforated impaction plate. Ions formed in the ionization chamber are driven partly by electric fields through the perforated impaction plate into the analyzer. As a result, most of the gas sampled into the analyzer carries ionized vapors, even when the sample flow is very small, and even when the analyzer uses counterflow gas.

Abstract: A method to select ions based on their electrical mobility is described. Ions are separated in space, and a continuous flow of mobility filtered ions is produced at the outlet of the device, as in Differential Mobility Analyzers (DMAs). Yet, no high fluid velocity field is required, avoiding limitations associated in DMAs to flow unsteadiness. Instead, separation relies on the use of time-dependent electric fields. Separation is based on synchronizing the period of the field with the flight time of an ion from an inlet to an outlet for a particular electrical mobility. Unlike FAIMS, the new invention separates ions according to their absolute mobility within one or a few characteristic times for field variation, rather than via many tiny separation steps over many periods of field variation producing separation according to non-linearities in the mobility. Unlike conventional pulsating ion mobility spectrometry, a steady flow of ions is produced.

Abstract: Improvements are provided in the detection of atmospheric vapors by ionizing them near ambient pressure, and analyzing them as ions. Lowest detection limits of parts per quadrillion (ppq) concentrations are enabled by a combination of improvements, including the use of a filter to remove occasional intense signal from explosive particles. Several sources of chemical background are identified and solutions for their reduction or elimination are presented. Gains in response time may be achieved by operating at elevated temperature. When the ionizer is an electrospray source, the use of high boiling point solvents is indicated. An increased selectivity is achieved by operating a differential mobility analyzer (DMA) in series with a mass spectrometer. However, ppq sensitivities require various improvements in the DMA system including a special coupling to the ionizer, controlling the temperature in the DMA pump circuit, avoidance of induction on the DMA electrodes from heating devices, etc.

Abstract: A method and apparatus are described to increase the efficiency with which a sample vapor is ionized prior to being introduced into an analyzer. Excellent contact between the vapor and the charging agent is achieved in the ionization chamber by separating it from the analyzer by means of a perforated impaction plate. As a result, some desired fraction of the gas going into the analyzer or coming out of the analyzer can be controlled independently from the flow of sample through the ionization chamber. Furthermore, penetration into said ionization chamber of said desired fraction of the gas going into or out of the analyzer is minimized by controlling the dimensions of said perforated impaction plate. Ions formed in the ionization chamber are driven partly by electric fields through said hole in said perforated impaction plate into the inlet to the analyzer.

Abstract: A method and an apparatus are described to focus sharply a wide range of particle sizes for particles suspended in a relatively high flow rate of carrier gas. The particles are accelerated through a continuously converging ladder of smooth contractions, each designed such that: (i) the flow remains laminar at substantial Reynolds numbers; (ii) a certain band of particle sizes is focused in each contraction, without substantial defocusing of larger particle focused in one or several preceding contractions; (iii) the form, length, and ratio of entry to exit diameter of each contraction, as well as the number of consecutive contractions are chosen such that all particles within a given relatively wide range of sizes are focused at the end of the ladder of contraction steps into a relatively narrow focal region. The focusing apparatus coupled to a collector device constitutes a new type of virtual impactor, termed a focusing virtual impactor, which can also be used as a powerful particle concentrator.

Abstract: A method and apparatus are described to increase the efficiency with which a sample vapor is ionized prior to being introduced into an analyzer. Excellent contact between the vapor and the charging agent is achieved in the ionization chamber by separating it from the analyzer by means of a perforated impaction plate. As a result, some desired fraction of the gas going into the analyzer or coming out of the analyzer can be controlled independently from the flow of sample through the ionization chamber. Furthermore, penetration into said ionization chamber of said desired fraction of the gas going into or out of the analyzer is minimized by controlling the dimensions of said perforated impaction plate. Ions formed in the ionization chamber are driven partly by electric fields through said hole in said perforated impaction plate into the inlet to the analyzer.

Abstract: A method is described to perform on-line detection of stress levels or changes in humor of individuals. The approach is particularly advantageous because analysis can be performed in real time or, at least, comprising a delay shorter than 30 s, and because it is non-invasive and non-degrading; and actually the individual under study do not need to be aware of being studied. More specifically, the present invention is based on the analysis of lactic acid and other volatiles concentrations in the vapors released by the individual (through the skin and the breath). The inventors have proved that said concentrations respond nearly instantaneously when the individual is subjected to a sudden stressful stimulus.

Abstract: A method is described to select ions based on their electrical mobility. Ions are subjected to at least one full cycle of a time-dependent electric field. Ions are separated in space, and a continuous flow of filtered ions with a narrow range of selected mobility ions is produced at the outlet of the device, as in Differential Mobility Analyzers (DMAs). Yet, no high fluid velocity field is required, avoiding limitations associated in DMAs to flow unsteadiness, compressibility and turbulent transition. Instead, separation relies on the use of time-dependent ion trajectories generated by the time-dependent electric fields. Unlike FAIMS, full separation according to the mobility takes place within one or a few characteristic times for field variation, rather than via many tiny separation steps over many periods of field variation producing separation according to the mobility non-linearities in the mobility.

Abstract: A method and apparatus are described to increase the efficiency with which a sample vapor is ionized prior to being introduced into an analyzer. Excellent contact between the vapor and the charging agent is achieved in the ionization chamber by separating it from the analyzer by means of a perforated impaction plate. As a result, some desired fraction of the gas going into the analyzer or coming out of the analyzer can be controlled independently from the flow of sample through the ionization chamber. Furthermore, penetration into said ionization chamber of said desired fraction of the gas going into or out of the analyzer is minimized by controlling the dimensions of said perforated impaction plate. Ions formed in the ionization chamber are driven partly by electric fields through said hole in said perforated impaction plate into the inlet to the analyzer.

Abstract: Medical catheters and catheter drainages can be difficult to disinfect. Infections produced by microorganisms swimming upstream through said catheters and catheter drainages are thus difficult to eliminate. A method to detach flagella propelled microorganisms from walls and to countermeasure their ability to swim upstream against the velocity of the fluid in ducts is described. Observations show that flagella propelled microorganisms require the forces and torques induced by the proximity of a wall and also by a velocity gradient produced near the wall of said ducts. The method is based on detaching said flagella propelled microorganisms from the walls by means of sharp edges. The flagella propelled microorganism can not change its swimming direction so abruptly to follow the geometry of said sharp edge and therefore it detaches from the wall. Once said microorganism is detached from the wall, it is flushed downstream by the velocity of the fluid which is stronger once far from the wall.

Abstract: A method and an apparatus are described to focus sharply a wide range of particle sizes for particles suspended in a relatively high flow rate of carrier gas. The particles are accelerated through a continuously converging ladder of smooth contractions, each designed such that: (i) the flow remains laminar at substantial Reynolds numbers; (ii) a certain band of particle sizes is focused in each contraction, without substantial defocusing of larger particle focused in one or several preceding contractions; (iii) the form, length, and ratio of entry to exit diameter of each contraction, as well as the number of consecutive contractions are chosen such that all particles within a given relatively wide range of sizes are focused at the end of the ladder of contraction steps into a relatively narrow focal region. The focusing apparatus coupled to a collector device constitutes a new type of virtual impactor, termed a focusing virtual impactor, which can also be used as a powerful particle concentrator.