Thermionic ionization detector with flow-through thermionic source
AssigneeHewlett-Packard Company
InventorsBruce W. Hermann, Richard P. White
Life of this patent
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Abstract
Method and apparatus for the thermionic ionization detection of one or more particular constituent components of a sample that is present in a fluid mixture. The fluid mixture flows across the interior surface of a central bore in a heated and appropriately sensitized "flow-through" thermionic source. The constituent components are ionized by an ionization process in which electrical charge is transferred from the thermionic source and converted into gas phase ion species. The current of gaseous ions is collected and measured at a collector electrode adjacent to the thermionic source.
Claims11
A thermionic ionization detector for detecting the presence of a constituent component of a sample in a first fluid, comprising:
- a fluid mixing structure for providing a fluid mixture flow that includes the first fluid;
- a flow-through thermionic source having a matrix including an alkali metal compound that is capable of ionization of the constituent component to produce an ion current when operated at an elevated temperature, the matrix having an interior surface that defines a central bore;
- a collector electrode for receiving the ion current;
- a fluid-directing structure for aligning the flow-through thermionic source and the collector electrode in a spaced relationship and for confining substantially all of the fluid mixture flow through the central bore of the thermionic source to the collector electrode;
- and
- an ion current measurement device for determining the ion current received by the collector electrode.
A thermionic ionization detector for detecting the presence of a constituent component of a sample in a first fluid, comprising:
- a fluid mixing structure for providing a fluid mixture flow that includes the first fluid, a first detector fluid, and a second detector fluid;
- a flow-through thermionic source having a matrix including an alkali metal compound that is capable of ionization of the constituent component to produce an ion current when operated at an elevated temperature, wherein the matrix includes an amorphous glassy composition formed to include an interior surface that defines a central bore;
- a collector electrode for receiving the ion current;
- a fluid-directing structure for coaxially aligning the central bore of the thermionic source and the collector body in a spaced relationship and for confining substantially all of the fluid mixture flow through the central bore of the thermionic source to the collector electrode;
- and
- an ion current measuring device for determining the ion current received by the collector electrode.
A method for detecting the presence of a constituent component of a sample in a first fluid, comprising the steps of:
- providing a flow-through thermionic source having a matrix including an alkali metal compound which is capable of ionization of the constituent component to produce an ion current when operated at an elevated temperature, the matrix having an interior surface that defines a central bore;
- providing a collector electrode for receiving the ion current;
- aligning the flow-through thermionic source and the collector electrode in a spaced relationship;
- providing a fluid mixture flow that includes the first fluid;
- confining substantially all of the fluid mixture flow through the central bore of the thermionic source to the collector electrode;
- and
- determining the ion current received by the collector electrode and, in response, indicating the presence of the constituent component.
Dependencies are inferred from the claim text.