Patent application number | Description | Published |
20080203290 | Method and apparatus to accurately discriminate gas phase ions with several filtering devices in tandem - A method for fast and accurate recognition of species contained in trace amounts in complex mixtures such as ambient air or biological fluids is taught based on the use in tandem of one or several differential mobility analyzers (DMAs) and possibly also a mass spectrometer (MS), all arranged in series. The two DMAs operate in different regions of the ion drag versus drift velocity curve (for instance, linear versus nonlinear regions), hence separating according to more than one independently discriminating parameters of the ion. Very high discrimination can be achieved even with a single stage of mass spectrometric separation by selecting a narrow range of ions with the DMA, and analyzing them in the MS, first without fragmentation, and then with fragmentation. This process does not require necessarily a tandem MS when fragmentation takes place in the inlet region of the MS. Fast and accurate discrimination is possible in single ion monitoring mode (SIM) for a large number of targeted species, even with relatively inexpensive and light single quadrupole MS systems, where the various filters placed in series would open pre-configured narrow windows suitable for passage of each ion in a list. | 08-28-2008 |
20080206106 | Method and apparatus for rapidly concentrating particles for analysis of explosives - A fast alternative for detecting dangerous or illegal substances is taught that improves upon the relatively slow conventional batch method of collecting and concentrating particles in filters. The new method concentrates the particles on-line and almost instantaneously, taking advantage of their inertia. Particles are thus concentrated on the fly from a large gas sample flow rate into a small gas flow rate, where they are rapidly volatilized and their vapors sensed in an analytical instrument such as a mass spectrometer or an ion mobility spectrometer. | 08-28-2008 |
20080251714 | Resolution improvement in the coupling of planar differential mobility analyzers with mass spectrometers or other analyzers and detectors - Prior work on differential mobility analysis (DMA) combined with mass spectrometry (MS) has shown how to couple the output of the DMA with the inlet of an atmospheric pressure ionization mass spectrometer (APCI-MS). However, the conventional ion inlet to an APCI-MS is a round orifice, while conventional DMA geometries make use of elongated slits. The coupling of two systems with such different symmetries limits considerably the resolutions attainable by the DMA in a DMA-MS combination below the value of the DMA alone. The purpose of this invention is to overcome this limitation in the case of a parallel plate DMA. One solution involves use of an elongated rather than a circular MS sampling hole, with the long dimension of the MS inlet hole aligned with that of the DMA slit. Another involves use of a more elongated orifice in the DMA exit and a more circular hole on the MS inlet, the two being connected either through a short transfer conduit or through an ion guide. The DMAs described can also be coupled profitably to detectors and analyzers other than mass spectrometers. | 10-16-2008 |
20090309014 | Method and apparatus to sharply focus aerosol particles at high flow rate and over a wide range of sizes - 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. | 12-17-2009 |
20100213366 | COUPLING BETWEEN AXISYMMETRIC DIFFERENTIAL MOBILITY ANALYZERS AND MASS SPECTROMETERS OR OTHER ANALYZERS AND DETECTORS - Prior work on differential mobility analysis (DMA) combined with mass spectrometry (MS) has shown how to couple the output of a planar DMA with the atmospheric pressure inlet of an atmospheric pressure ionization mass spectrometer (APCI-MS). However, because the ion inlet to APCI-MS instruments is a round orifice, while conventional DMA geometries make use of elongated slits, the coupling of both has attained less resolving power or tolerated a smaller sample flow rate than a DMA alone. The present invention overcomes these limitations with an axial DMA of cylindrical symmetry using more than two electrodes. The configuration is related to that previously proposed by Labowsky and Fernández de la. Mora (2004, 2006), where ions with a critical electrical mobility are brought into the symmetry axis of the DMA. Ions with this critical mobility are now optimally transmitted into the MS, with much higher resolution than possible in planar DMAs. In a preferred embodiment of this DMA facilitating DMA-MS coupling, one DMA electrode intersecting the symmetry axis is relatively planar. | 08-26-2010 |
20100264304 | Method for detecting volatile species of high molecular weight - Vapors of relatively heavy species having molecular weights in excess of 290 amu have not been previously detected in the gas phase at ambient temperature. A method to detect them is taught here based on the use of a mass spectrometer with an atmospheric pressure source. Ions produced in detectable quantities from such heavy vapors are claimed as a new state of matter. | 10-21-2010 |
20110049356 | Use Ion Guides With Electrodes of Small Dimensions to Concentrate Small Charged Species in a Gas at Relatively High Pressure - The present invention is based on the observation that radio frequency (RF) electric fields in multi-pole lenses with small rod diameters in the range of 1 mm enables strongly concentrating ions suspended in a gas at pressures much higher than previously used for ion manipulation, including atmospheric pressure. Other lens configurations are described, including one based on the funnels of U.S. Pat. No. 6,107,628, and another on the coiled wire system of Hutchins et al. (1999). The finding provides a method to increase the concentration of ions transmitted to mass spectrometers and other analyzers, both from volatile or involatile species in solution, hence increasing their analytical sensitivity. It also enables improved charging efficiencies of neutral volatile species existing in the gas phase. | 03-03-2011 |
20110057096 | METHOD AND APPARATUS TO ACCURATELY DISCRIMINATE GAS PHASE IONS WITH SEVERAL FILTERING DEVICES IN TANDEM - A method for fast and accurate recognition of species contained in trace amounts in complex mixtures such as ambient air or biological fluids is taught based on the use in tandem of one or several differential mobility analyzers (DMAs) and possibly also a mass spectrometer (MS), all arranged in series. The two DMAs operate in different regions of the ion drag versus drift velocity curve (for instance, linear versus nonlinear regions), hence separating according to more than one independently discriminating parameters of the ion. Very high discrimination can be achieved even with a single stage of mass spectrometric separation by selecting a narrow range of ions with the DMA, and analyzing them in the MS, first without fragmentation, and then with fragmentation. This process does not require necessarily a tandem MS when fragmentation takes place in the inlet region of the MS. Fast and accurate discrimination is possible in single ion monitoring mode (SIM) for a large number of targeted species, even with relatively inexpensive and light single quadrupole MS systems, where the various filters placed in series would open pre-configured narrow windows suitable for passage of each ion in a list. | 03-10-2011 |
20120325024 | Method for Detecting Atmospheric Vapors at Parts per Quadrillion (PPQ) Concentrations - 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. | 12-27-2012 |