ATMOSPHERIC PRESSURE IONIZATION MASS SPECTROMETER

摘要

In an atmospheric pressure ionization source using an ESI or the like having a desolvation pipe with one end opening serving as an ion-drawing port, a drying-gas supplying port for supplying a drying gas against the ion-drawing direction is provided below the ion-drawing port, i.e. at a position opposite to the side where a nozzle for spraying a liquid sample into an atmospheric pressure atmosphere is located, as viewed from the ion-drawing port. When the drying gas is supplied from the drying-gas supplying port, the gas pressure becomes higher in a region above the ion-drawing port becomes higher than in a region below the same port and produces a downward air stream. This stream helps ions in the spray flow from the nozzle to easily come close to the ion-drawing port and be efficiently drawn into the desolvation pipe.

主权项

1. An atmospheric pressure ionization mass spectrometer having: a spray device for spraying a liquid into an ionization chamber whose inner space is maintained at atmospheric pressure; and an ion-drawing port for drawing ions generated from micro droplets sprayed from the spray device so as to transport the ions to a subsequent stage maintained at a low gas pressure, the central axis of the ion-drawing port being unidentical with the central axis of a spray flow from the spraying device, wherein:
the mass spectrometer includes a drying-gas supplying port located in a region surrounding the ion-drawing port and at least on a side of the central axis of the ion-drawing port opposite to a side where the spray port of the spraying device is located, the drying-gas supplying port being arranged so as to supply a drying gas in a direction opposite to a direction in which ions are drawn through the ion-drawing port; and the drying gas is supplied only from the aforementioned drying-gas supplying port.