Abstract: Methods and devices for detecting a target substance on a subject without contacting the subject are disclosed. At least one air jet blows analyte from a surface of the subject into an airflow, the airflow entraining the analyte. A desorption channel desorbs molecules from analyte in a portion of the airflow travelling through the desorption channel. An ionizer forms ions from vapour molecules in the portion of the airflow. At least one mass spectrometer analyzes the ions to detect the target substance. The airflow travels without interruption from the subject to the at least one mass spectrometer. The desorption channel causes a sufficient quantity of molecules to desorb from the analyte to enable the at least one mass spectrometer to detect the target substance.

Abstract: Methods and devices for detecting a target substance on a subject without contacting the subject are disclosed. At least one air jet blows analyte from a surface of the subject into an airflow, the airflow entraining the analyte. A desorption channel desorbs molecules from analyte in a portion of the airflow travelling through the desorption channel. An ionizer forms ions from vapor molecules in the portion of the airflow. At least one mass spectrometer analyzes the ions to detect the target substance. The flow travels without interruption from the subject to the at least one mass spectrometer. The desorption channel causes a sufficient quantity of molecules to desorb from the analyte to enable the at least one mass spectrometer to detect the target substance.

Abstract: Processing a liquid sample (204) having an analyte (206) by reducing a pressure in a container (200) including the liquid sample to less than atmospheric pressure and maintaining a reduced pressure in the container. Reducing the pressure in the container (200) and optionally agitating the liquid sample increases an amount of vapor-phase analyte (206) above the liquid sample. In some cases, a concentration of the vapor-phase analyte is further increased, for example, with a chemical trap (502). The vapor-phase analyte can be provided to a chemical analyzer (302).

Abstract: Methods and devices for detecting a target substance on a subject without contacting the subject are disclosed. At least one air jet blows analyte from a surface of the subject into an airflow, the airflow entraining the analyte. A desorption channel desorbs molecules from analyte in a portion of the airflow travelling through the desorption channel. An ionizer forms ions from vapour molecules in the portion of the airflow. At least one mass spectrometer analyzes the ions to detect the target substance. The flow travels without interruption from the subject to the at least one mass spectrometer. The desorption channel causes a sufficient quantity of molecules to desorb from the analyte to enable the at least one mass spectrometer to detect the target substance.

Abstract: In the field of mass spectrometry, a method and apparatus for fragmenting ions with a relatively high degree of resolution and efficiency. The technique includes trapping the ions in a linear ion trap, in which the background or neutral gas pressure is preferably on the order of 10-5 Torr. The trapped ions are resonantly excited for a relatively extended period of time, e.g., exceeding 50 ms, at relatively low excitation levels, e.g., less than 1 Volt (0-pk). The technique allows selective dissociation of ions with a high discrimination. High fragmentation efficiency may be achieved by superimposing a higher order multipole field onto the quadrupolar RF field used to trap the ions. The multipole field, preferably an octopole field, dampens the radial oscillatory motion of resonantly excited ions at the periphery of the trap. This reduces the probability that ions will eject radially from the trap thus increasing the probability of collision induced dissociation.

Abstract: In the field of mass spectrometry, a method and apparatus for fragmenting ions with a relatively high degree of resolution and efficiency. The technique includes trapping the ions in a linear ion trap, in which the background or neutral gas pressure is preferably on the order of 10?5 Torr. The trapped ions are resonantly excited for a relatively extended period of time, e.g., exceeding 50 ms, at relatively low excitation levels, e.g., less than 1 Volt(0-pk). The technique allows selective dissociation of ions with a high discrimination. High fragmentation efficiency may be achieved by superimposing a higher order multipole field onto the quadrupolar RF field used to trap the ions. The multipole field, preferably an octopole field, dampens the radial oscillatory motion of resonantly excited ions at the periphery of the trap. This reduces the probability that ions will eject radially from the trap thus increasing the probability of collision induced dissociation.

Abstract: The invention solves the problem of artifact ghost peaks which can sometimes arise in mass spectrometers that employ a quadrupole rod set for both trapping and mass analyzing the trapped ions. The problem arises as a result of randomly distributed voltage gradients along the length of the rods. Three solutions are presented. The first approach involves improving the conduction characteristics of the rod sets. The second approach involves the application of at least one continuous axial DC field to the trapping quadrupole rod set in order to urge ions towards a pre-determined region of the trap, thereby avoiding voltage gradients. The third approach involves the application of one or more discrete axial fields to create one or more potential barriers along the axial dimension of the trap (in addition to the barriers used to initially trap the ions). These barriers prevent ions of differing voltage gradients from equilibrating with one another.

Abstract: An improved method of operating a mass spectrometer having a linear ion trap wherein ions are axially ejected from the trap to a detector or subsequent mass analysis stage. The DC barrier field produced at the exit lens of the trap is scanned in conjunction with the scanning of other fields used to energize ions of select mass-to-charge ratios past the barrier field/exit lens. The technique can maximize the resolution obtainable from axial ejection over a wide mass range.

Abstract: The invention solves the problem of artifact ghost peaks which can sometimes arise in mass spectrometers that employ a quadrupole rod set for both trapping and mass analyzing the trapped ions. The problem arises as a result of randomly distributed voltage gradients along the length of the rods. Three solutions are presented. The first approach involves improving the conduction characteristics of the rod sets. The second approach involves the application of at least one continuous axial DC field to the trapping quadrupole rod set in order to urge ions towards a pre-determined region of the trap, thereby avoiding voltage gradients. The third approach involves the application of one or more discrete axial fields to create one or more potential barriers along the axial dimension of the trap (in addition to the barriers used to initially trap the ions). These barriers prevent ions of differing voltage gradients from equilibrating with one another.

Abstract: An improved method of operating a mass spectrometer having a linear ion trap wherein ions are axially ejected from the trap to a detector or subsequent mass analysis stage. The DC barrier field produced at the exit lens of the trap is scanned in conjunction with the scanning of other fields used to energize ions of select mass-to-charge ratios past the barrier field/exit lens. The technique can maximize the resolution obtainable from axial ejection over a wide mass range.

Abstract: In the field of mass spectrometry, a method and apparatus for fragmenting ions with a relatively high degree of resolution. The technique includes trapping the ions in an ion trap, preferably a linear ion trap, in which the background or neutral gas pressure is preferably on the order of 10−5 Torr. The trapped ions are resonantly excited for a relatively extended period of time, e.g., exceeding 50 ms, at relatively low excitation levels, e.g., less than 1V(0−pk). The technique allows selective dissociation of ions with a discrimination of at least about 1 m/z at a practical fragmentation efficiencies. Apparatus and related methods are also disclosed for obtaining MS, MS2, MS3 and MSn spectrums at relatively high resolutions using the low pressure fragmentation technique.

Abstract: In the field of mass spectrometry, a method and apparatus for fragmenting ions with a relatively high degree of resolution and efficiency. The technique includes trapping the ions in a linear ion trap, in which the background or neutral gas pressure is preferably on the order of 10−5 Torr. The trapped ions are resonantly excited for a relatively extended period of time, e.g., exceeding 50 ms, at relatively low excitation levels, e.g., less than 1 Volt(0-pk). The technique allows selective dissociation of ions with a high discrimination. High fragmentation efficiency may be achieved by superimposing a higher order multipole field onto the quadrupolar RF field used to trap the ions. The multipole field, preferably an octopole field, dampens the radial oscillatory motion of resonantly excited ions at the periphery of the trap. This reduces the probability that ions will eject radially from the trap thus increasing the probability of collision induced dissociation.

Abstract: A disposable plastic cartridge contains three fine lightweight wire mesh collectors, each of phosphor bronze. One collector has an oxidized surface for collecting drug particulates. The other two have surfaces electroplated with zinc to form a rough multi-fissured surface for trapping low volatility vapors. In use, a portion of a warm sample air stream is chilled and passed through the collectors in parallel for sample collection. Simultaneously part of the sample air stream by-passes the chiller and is fed directly into a mass analyzer for real time analysis. Next, both collection and real time analysis are terminated, and each collector is desorbed in sequence with a pulse of hot air which flows into the mass analyzer for sequential analysis.