Discharge ionization current detector
US8421470B2 · kind B2 · utility
Assignees
Inventors
Key dates
| Filing date | Mar 19, 2009 |
| Grant date | Apr 16, 2013 |
| Priority date | — |
| Expiry date | Nov 17, 2029 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N2030/642
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
A low-frequency high AC voltage from an excitation voltage power source (14) is applied between one electrode (8) and two other electrodes (9A and 9B) to generate a low-frequency AC-excited dielectric barrier discharge within a gas passage (3), thereby creating atmospheric pressure non-equilibrium micro-plasma. A sample gas is mixed with hydrogen inside the passage of a nozzle (51), and further mixed with air outside an exit port (53) to burn, forming a hydrogen flame (57). Then, the sample gas reaches an ionization area (56), where the sample components are ionized due to the effect of light emitted from the plasma. Meanwhile, water molecules generated in the hydrogen flame (57) are supplied into the ionization area (56), whereby some of the sample-molecule ions are hydrated while the others undergo a reaction to form a hydroxonium ion. These kinds of hydrated ions have long lifetimes and barely become extinct halfway, so that they can efficiently reach a detection electrode (13) and be detected as ion current. As a result, the detection sensitivity is improved and the dynamic range is enhanced.
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.