Electrospray ionization source and method of using the same
US5788166A · kind A · utility
Assignee
Inventors
Key dates
| Filing date | Aug 27, 1996 |
| Grant date | Aug 4, 1998 |
| Priority date | — |
| Expiry date | Aug 27, 2016 |
Classification
- Technology area (CPC G)Physics
- CPC primaryG01N27/44717
- WIPO fieldMeasurement
- WIPO sectorInstruments
Abstract
An ultra-low flow rate electrospray ionization (ESI) source provides flow rates in the range of 1.0 nL/min or less. The source is comprised of a needle which is fabricated by laser-heated pulling of fused-silica tubing, followed by chemical etching and surface metallization. The pulling results in formation of a slowly tapering capillary within the needle which tapers to a tip having a very small inner diameter. The etching process sharpens the outer wall of the needle to a very sharp tip, and the combination of these parameters results in the ultra-low flow rate capability. After a metal electrical contact is formed on the exterior wall of the needle, an electrically insulating overcoating is preferably deposited thereon which locks the contact in place, thereby greatly increasing needle life, and also restricting the electrical contact point to the very tip of the needle. Although the use of the ultra-low flow rate ESI sources increases sensitivity to sampling errors, a mechanism is also provided to minimize one primary source of such errors, evaporation induced hydrodynamic flow, in capillary electrophoresis (CE). An injection system is provided which enables a retractable dropl…
Source: USPTO / EPO open patent data. Objective bibliographic and citation counts.